Discourse

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TODO

List of outstanding tasks before attempting to install Discourse on production:

  1. iptables rules that prevent the discourse app from being able to initiate calls to the Internet (it should *only* be able to *respond* to queries) as we do for our apache backend by blocking non-established traffic from going through the OUTPUT table by the apache uid
    1. TODO: test an upgrade after this is done as well.
  2. OWASP CORS rules to prevent sqli/XSS/etc attacks as we do in apache
    1. update the install-nginx script so that it compiles nginx with mod_security (and probably downloads the OWASP CRS as well) https://github.com/discourse/discourse_docker/blob/416467f6ead98f82342e8a926dc6e06f36dfbd56/image/base/install-nginx
    2. add a new templates/web.modsecurity.yml file that updates the /etc/nginx/conf.d/discourse.conf file to enable mod_security (and add some blacklisted rules as-needed), similar to the existing web.socketed.template.yml file https://github.com/discourse/discourse_docker/blob/416467f6ead98f82342e8a926dc6e06f36dfbd56/templates/web.socketed.template.yml
  3. Minimum/hardened permissions of the /var/discourse dir
  4. iptables on docker container instead of total internet blocking so the docker container can actually update its own OS packages?
    1. TODO: document update to `launcher` script's run_start() function's final `docker run` command to add the argument '--add-cap=NET_ADMIN' so the docker container root's user has permission to modify iptables rules.
  5. Varnish cache https://meta.discourse.org/t/does-discourse-container-use-unattended-upgrades/136296
  6. Fix unattended-upgrade https://meta.discourse.org/t/does-discourse-container-use-unattended-upgrades/136296
  7. Test/document Discourse upgrade process
  8. Test/document backup & restore process
  9. Stable cron job for docker image cleanup to prevent disk-fill

Useful Commands

This section will describe useful commands when working with Discourse 

# get docker info
docker info

# list running docker containers
docker ps

# list all docker containers
docker ps -a

# list all docker images
docker image list

# get docker disk usage (including reclaimable space)
docker system df

# get a shell on the Discourse's docker container
/var/discourse/launcher enter discourse_ose

# access the rails console (exec from inside the docker container)
rails c

# restart a process from within the docker container (ie: cron, nginx, postgres, redis, rsyslog, unicorn)
sv stop nginx && sv start nginx

# stop/start/restart the Discourse container
/var/discourse/launcher stop discourse_ose
/var/discourse/launcher start discourse_ose
/var/discourse/launcher restart discourse_ose

# "rebuild" Discourse app (ie: for upgrades or changes to "templates/" yaml files)
# Takes 5-20 minutes to run, and it may break. Test on staging first.
/var/discourse/launcher rebuild discourse_ose

# get capabilities of discourse docker container
id=`docker inspect --format="{{.Id}}" discourse_ose`
grep -E 'CapAdd|CapDrop|Capabilities' /var/lib/docker/containers/$id/hostconfig.json

Troubleshooting

This section will provide tips on how to troubleshoot the Discourse install

Important Files & Directories

For more information about our Discourse configuration, please see the following files & directories on the Docker Host: 

/var/discourse/
/var/discourse/launcher
/var/discourse/containers/discourse_ose.yml
/var/discourse/templates/
/var/discourse/templates/templates/iptables.template.yml
/var/discourse/templates/templates/postgres.template.yml
/var/discourse/templates/templates/redis.template.yml
/var/discourse/templates/templates/web.template.yml
/var/discourse/templates/templates/web.ratelimited.template.yml
/var/discourse/templates/templates/web.socketed.template.yml
/var/discourse/templates/templates/web.modsecurity.template.yml
/var/discourse/image/base/
/var/discourse/image/base/Dockerfile
/var/discourse/image/base/install-nginx

And the following logs may be helpful: 

/var/discourse/shared/standalone/log/rails/production.log
/var/discourse/shared/standalone/log/rails/unicorn.stderr.log
/var/discourse/shared/standalone/log/var-log/redis/current
/var/discourse/shared/standalone/log/var-log/nginx/{access.log,error.log}
/var/discourse/shared/standalone/log/var-log/postgres/current

And the following files & directories inside the Discourse Docker Container: 

/var/www/discourse/
/var/www/discourse/public
/etc/nginx/conf.d/discourse.conf

Unable to Connect

Relevant error messages:

  • cURL
Failed to connect to discourse.opensourceecology.org port 80: Connection refused
  • Firefox
Unable to connect

Firefox can’t establish a connection to the server at discourse.opensourceecology.org.

    The site could be temporarily unavailable or too busy. Try again in a few moments.
    If you are unable to load any pages, check your computer’s network connection.
    If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.
  • Chromium
This site can’t be reached discourse.opensourceecology.org refused to connect.
Try:

Checking the connection
Checking the proxy and the firewall
ERR_CONNECTION_REFUSED

This is because literally nothing is responding on the ip address and port. There's actually two nginx processes to debug:

  1. nginx running on the server
  2. nginx running on the discourse container running on the server

Make sure you debug both!

`git pull` fail

The built-in Discourse 'launcher' script may try to do a `git pull` that may fail when it tries to update a file that we've modified in OSE's config. For example: 

[root@osestaging1 discourse]# /var/discourse/launcher rebuild discourse_ose
Ensuring launcher is up to date
Fetching origin
remote: Enumerating objects: 6, done.
remote: Counting objects: 100% (6/6), done.
remote: Compressing objects: 100% (4/4), done.
remote: Total 6 (delta 2), reused 2 (delta 2), pack-reused 0
Unpacking objects: 100% (6/6), done.
From https://github.com/discourse/discourse_docker
   bb9a173..b0c92ba  master     -> origin/master
Updating Launcher
Updating bb9a173..b0c92ba
error: Your local changes to the following files would be overwritten by merge:
		launcher
Please, commit your changes or stash them before you can merge.
Aborting
failed to update
Ensuring launcher is up to date
Fetching origin
Updating Launcher
Updating bb9a173..b0c92ba
error: Your local changes to the following files would be overwritten by merge:
		launcher
Please, commit your changes or stash them before you can merge.
Aborting
failed to update
Ensuring launcher is up to date
Fetching origin
Updating Launcher
Updating bb9a173..b0c92ba
...

The above output was an endless loop complaining about the conflict between the file 'launcher' in the '/var/discourse/' directory. In order to fix the conflict, you must merge the changes--which may be a non-trivial process.

The easiest action is to just move the locally modified files out of the way, do a clean `git pull`, make note a diff of the changes, and re-apply the local changes by re-visiting the relevant section of install guide. For detailed instructions on this process, see the "Updating Discourse" #Step 3: Update git section.

2019-11 Install Guide

In 2019-11, I (Michael Altfield) tested an install of Discourse on the OSE Staging Server. I documented the install steps here so they could be exactly reproduced on production

Install Prereqs

First we have to install docker. The version in the yum repos (1.13.1) was too old to be supported by Discourse (which states it requires a minimum of 17.03.1).

Note that the install procedure recommended by Docker and Discourse for Docker is a curl piped to shell. This should never, ever, ever be done. The safe procedure is to manually add the gpg key and repo to the server as get.docker.org script should do -- assuming it were not modified in transit. Note that Docker does *not* cryptographically sign their install script in any way, and it therefore cannot be safely validated.

The gpg key itself is available at the following URL from docker.com 

* https://download.docker.com/linux/centos/gpg

Please do your due diligence to validate that this gpg key is the official key and was not manipulated in-transit by Mallory. Unfortunately, at the time of writing, this is non-trivial since there's no signatures on the key, the key is not uploaded to any public keyservers, the docker team doesn't have a keybase account, etc. I submitted a feature request to the docker team's 'for-linux' repo asking them to at least upload this gpg key to the keys.openpgp.org keyserver on 2019-11-12 [1]

After installing the docker gpg file to '/etc/pki/rpm-gpg/docker.gpg', execute the following commands as root to install docker: 

# first, install the (ASCII-armored) docker gpg key to /etc/pki/rpm-gpg/docker.gpg
cp docker.gpg /etc/pki/rpm-gpg/docker.gpg
chown root:root /etc/pki/rpm-gpg/docker.gpg
chmod 0644 /etc/pki/rpm-gpg/docker.gpg

# and install the repo
cat > /etc/yum.repos.d/docker-ce.repo  <<'EOF'
[docker-ce-stable]
name=Docker CE Stable - $basearch
baseurl=https://download.docker.com/linux/centos/7/$basearch/stable
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/docker.gpg
EOF

# finally, install docker from the repos
yum install docker-ce

Now execute the following commands as root to make docker start on system boot & start it up. 

systemctl enable docker.service
systemctl start docker.service

Install Discourse

In this step we will configure & install the Discourse docker container and all its components

Clone Repo

From the Disourse Install Guide, checkout the github repo as root to /var/discourse. You'll want to validate that this wasn't modified in transit; there are no cryptographic signatures to validate authenticity of the repo's contents here. A huge failing on Discourse's part (but, again, Discourse's sec is rotten from its foundation in Docker; see above).

Execute the following as root to populate the '/var/discourse/' directory: 

sudo -s
git clone https://github.com/discourse/discourse_docker.git /var/discourse
cd /var/discourse

Create container yaml

Now, the next step of the official Discourse 'INSTALL-cloud' guide is to use the `./discourse-setup` script, but--at the time of writing--that script doesn't support building a config for servers that have an MTA running on the server without auth (ie: most linux servers on the net, whose MTA isn't accessible over the internet and instead just handle traffic over 127.0.0.1 and don't require auth--like our server is setup).

But we need to run this `./discourse-setup` script once just to generate a template 'app.yml' config file before proceeding. When it asks you for a hostname, enter 'discourse.example.com', which will cause it to fail but generate the 'containers/app.yml' file that we need so we can proceed with manual install.

Execute the commands shown in the example below as root, inputting to the prompts matching what is shown: 

[root@osestaging1 discourse]# ls containers/
[root@osestaging1 discourse]# 
[root@osestaging1 discourse]# ./discourse-setup 
which: no docker.io in (/sbin:/bin:/usr/sbin:/usr/bin)
which: no docker.io in (/sbin:/bin:/usr/sbin:/usr/bin)
./discourse-setup: line 275: netstat: command not found
./discourse-setup: line 275: netstat: command not found
Ports 80 and 443 are free for use
‘samples/standalone.yml’ -> ‘containers/app.yml’
Found 1GB of memory and 1 physical CPU cores
setting db_shared_buffers = 128MB
setting UNICORN_WORKERS = 2
containers/app.yml memory parameters updated.

Hostname for your Discourse? [discourse.example.com]: discourse.example.com

Checking your domain name . . .
WARNING:: This server does not appear to be accessible at discourse.example.com:443.

A connection to http://discourse.example.com (port 80) also fails.

This suggests that discourse.example.com resolves to the wrong IP address
or that traffic is not being routed to your server.

Google: "open ports YOUR CLOUD SERVICE" for information for resolving this problem.

If you want to proceed anyway, you will need to
edit the containers/app.yml file manually.
[root@osestaging1 discourse]#

Verify the change from the previous commands by confirming the existence of the 'containers/app.yml' file. 

[root@osestaging1 discourse]# ls containers/
app.yml
[root@osestaging1 discourse]#

The default name of the Discourse docker container is 'app'. Let's rename that to 'discourse_ose'.

Execute the following command as root to update th container's yaml file name: 

mv containers/app.yml containers/discourse_ose.yml

Verify the change from the previous command by confirming that the file is now named 'discourse_ose.yml' 

[root@osestaging1 discourse]# ls containers/
discourse_ose.yml
[root@osestaging1 discourse]#

SMTP

The Discourse install script doesn't support the very simple config of an smtp server running on localhost:25 without auth. That is to say, Discourse doesn't support the default postfix config for RHEL/CentOS and most web servers on the net..

We have to manually edit the /var/discourse/containers/discourse_ose.yml

Note that 'localhost' resolves to the IP Address of the container created by docker when referenced from within the context of Discourse, but our smtp server is running on the host server. Therefore, we cannot use 'localhost' for the DISCOURSE_SMTP_ADDRESS. Instead, we use the IP Address of the host server's docker0 interface. In this case, it's 172.17.0.1, and that can be verified via the output of `ip address show dev docker0` run on the host where docker is installed (in this case, osestaging1).

First, let's comment-out any existing SMTP-related environment variables defined in the yml file.

Execute the following command as root to comment-out the SMTP-related lines in the yaml file: 

sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^\([^#]*\)\(DISCOURSE_SMTP.*\)$%\1#\2%' /var/discourse/containers/discourse_ose.yml

Now execute the following commands as root to add our SMTP settings to the 'env:' section: 

grep 'DISCOURSE_SMTP_ADDRESS: 172.17.0.1' /var/discourse/containers/discourse_ose.yml || sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^env:$%env:\n  DISCOURSE_SMTP_ADDRESS: 172.17.0.1 # this is the IP Address of the host server on the docker0 interface\n  DISCOURSE_SMTP_PORT: 25\n  DISCOURSE_SMTP_AUTHENTICATION: none\n  DISCOURSE_SMTP_OPENSSL_VERIFY_MODE: none\n  DISCOURSE_SMTP_ENABLE_START_TLS: false\n%' /var/discourse/containers/discourse_ose.yml

Verify the previous two changes by confirming that your 'discourse_ose.yml' config file now looks something like this. Note the addition of the 'DISCOURSE_SMTP_*' lines immediately under the 'env:' block and that the following 'DISCOURSE_SMTP_*' lines are commented-out. 

[root@osestaging1 discourse]# grep -C1 'DISCOURSE_SMTP' /var/discourse/containers/discourse_ose.yml
env:
  DISCOURSE_SMTP_ADDRESS: 172.17.0.1 # this is the IP Address of the host server on the docker0 interface
  DISCOURSE_SMTP_PORT: 25
  DISCOURSE_SMTP_AUTHENTICATION: none
  DISCOURSE_SMTP_OPENSSL_VERIFY_MODE: none
  DISCOURSE_SMTP_ENABLE_START_TLS: false

--
  # WARNING the char '#' in SMTP password can cause problems!
  #DISCOURSE_SMTP_ADDRESS: smtp.example.com
  #DISCOURSE_SMTP_PORT: 587
  #DISCOURSE_SMTP_USER_NAME: user@example.com
  #DISCOURSE_SMTP_PASSWORD: pa$$word
  #DISCOURSE_SMTP_ENABLE_START_TLS: true           # (optional, default true)

[root@osestaging1 discourse]#

Also note that you will need to the postfix configuration (/etc/postfix/main.cf) to bind on the docker0 interface, change the 'mynetworks_style' from 'host' to nothing (comment it out), and add the docker0 subnet to the 'mynetworks' list to auth the Discourse docker client to be able to send mail through the smtp server.

Execute the following command as root to update the postfix config: 

grep 'mynetworks = 127.0.0.0/8, 172.17.0.0/16' /etc/postfix/main.cf || sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^mynetworks_style = host$%#mynetworks_style = host\nmynetworks = 127.0.0.0/8, 172.17.0.0/16%' /etc/postfix/main.cf

Verify the change above by confirming that your postfix 'main.cf' file now looks something like this. Note that the 'myhost_style' lines are all commented-out and that the 'mynetworks' line now includes '172.17.0.1'. 

root@osestaging1 discourse]# grep -E 'mynetworks|interfaces' /etc/postfix/main.cf
# The inet_interfaces parameter specifies the network interface
# the software claims all active interfaces on the machine. The
# See also the proxy_interfaces parameter, for network addresses that
#inet_interfaces = all
#inet_interfaces = $myhostname
#inet_interfaces = $myhostname, localhost
#inet_interfaces = localhost
inet_interfaces = 127.0.0.1, 172.17.0.1
# The proxy_interfaces parameter specifies the network interface
# the address list specified with the inet_interfaces parameter.
#proxy_interfaces =
#proxy_interfaces = 1.2.3.4
# receives mail on (see the inet_interfaces parameter).
# to $mydestination, $inet_interfaces or $proxy_interfaces.
# ${proxy,inet}_interfaces, while $local_recipient_maps is non-empty
# The mynetworks parameter specifies the list of "trusted" SMTP
# By default (mynetworks_style = subnet), Postfix "trusts" SMTP
# On Linux, this does works correctly only with interfaces specified
# Specify "mynetworks_style = class" when Postfix should "trust" SMTP
# mynetworks list by hand, as described below.
# Specify "mynetworks_style = host" when Postfix should "trust"
#mynetworks_style = class
#mynetworks_style = subnet
#mynetworks_style = host
# Alternatively, you can specify the mynetworks list by hand, in
# which case Postfix ignores the mynetworks_style setting.
#mynetworks = 168.100.189.0/28, 127.0.0.0/8
#mynetworks = $config_directory/mynetworks
#mynetworks = hash:/etc/postfix/network_table
mynetworks = 127.0.0.0/8, 172.17.0.0/16
# - from "trusted" clients (IP address matches $mynetworks) to any destination,
# - destinations that match $inet_interfaces or $proxy_interfaces,
# unknown@[$inet_interfaces] or unknown@[$proxy_interfaces] is returned
[root@osestaging1 discourse]#

Other container env vars

Now we will update the container's yaml file with the necessary environment variables.

Execute the following commands as root to set the DISCOURSE_DEVELOPER_EMAILS variable (and comment-out the existing one): 

sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^\([^#]*\)\(DISCOURSE_DEVELOPER_EMAILS.*\)$%\1#\2%' /var/discourse/containers/discourse_ose.yml
grep '^\s*DISCOURSE_DEVELOPER_EMAILS:' /var/discourse/containers/discourse_ose.yml || sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^env:$%env:\n  DISCOURSE_DEVELOPER_EMAILS: 'discourse.opensourceecology.org'\n\n%' /var/discourse/containers/discourse_ose.yml

Execute the following commands as root to set the DISCOURSE_HOSTNAME variable (and comment-out the existing one): 

sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^\([^#]*\)\(DISCOURSE_HOSTNAME.*\)$%\1#\2%' /var/discourse/containers/discourse_ose.yml
grep "DISCOURSE_HOSTNAME: 'discourse.opensourceecology.org'" /var/discourse/containers/discourse_ose.yml || sed --in-place=.`date "+%Y%m%d_%H%M%S"` "s%^env:$%env:\n  DISCOURSE_HOSTNAME: 'discourse@opensourceecology.org,ops@opensourceecology.org,marcin@opensourceecology.org,michael@opensourceecology.org'\n\n%" /var/discourse/containers/discourse_ose.yml

Verify the previous two changes by confirming that your 'discourse_ose.yml' config file now looks something like this. Note the addition of the 'DISCOURSE_HOSTNAME' and 'DISCOURSE_DEVELOPER_EMAILS' lines immediately under the 'env:' block and that the following 'DISCOURSE_HOSTNAME' and 'DISCOURSE_DEVELOPER_EMAILS' lines are commented-out. 

[root@osestaging1 discourse]# grep -C1 -E 'DISCOURSE_HOSTNAME|DISCOURSE_DEVELOPER_EMAILS' /var/discourse/containers/discourse_ose.yml
env:
  DISCOURSE_HOSTNAME: 'discourse@opensourceecology.org,ops@opensourceecology.org,marcin@opensourceecology.org,michael@opensourceecology.org'


  DISCOURSE_DEVELOPER_EMAILS: discourse.opensourceecology.org

--
  ## Required. Discourse will not work with a bare IP number.
  #DISCOURSE_HOSTNAME: 'discourse.example.com'

--
  ## on initial signup example 'user1@example.com,user2@example.com'
  #DISCOURSE_DEVELOPER_EMAILS: 'me@example.com,you@example.com'

[root@osestaging1 discourse]#

Nginx socket

Also, we already have nginx bound to port 443 as our ssl terminator, so the defaults in our container's yaml file will fail. Instead, we add the 'web.socketed.template.yml' file, remove the 'expose' block, and we'll setup nginx to proxy connections to the resulting discourse unix socket file [2]

Execute the following command as root to add the 'web.socketed.template.yml' template to the list of templates in the 'discourse_ose.yml' file. 

grep 'templates/web.socketed.template.yml' /var/discourse/containers/discourse_ose.yml || sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^  - "templates/web.template.yml"$%  - "templates/web.template.yml"\n  - "templates/web.socketed.template.yml"%' /var/discourse/containers/discourse_ose.yml

Verify the change from the above command by confirming that the container's yaml file now looks something like this. Note the addition of the 'web.socketed.template.yml' line immediately under the 'templates:' line. 

[root@osestaging1 discourse]# grep -C2 templates /var/discourse/containers/discourse_ose.yml
## visit http://www.yamllint.com/ to validate this file as needed

templates:
  - "templates/postgres.template.yml"
  - "templates/redis.template.yml"
  - "templates/web.template.yml"
  - "templates/web.socketed.template.yml"
  - "templates/web.ratelimited.template.yml"
## Uncomment these two lines if you wish to add Lets Encrypt (https)
  #- "templates/web.ssl.template.yml"
  #- "templates/web.letsencrypt.ssl.template.yml"

## which TCP/IP ports should this container expose?
[root@osestaging1 discourse]#

And now execute the following command as root to comment-out the entire "expose" block and all its contents: 

perl -i".`date "+%Y%m%d_%H%M%S"`" -p0e 's%expose:\n  -([^\n]*)\n  -([^\n]*)%#expose:\n#  -\1\n#  -\2%gs' /var/discourse/containers/discourse_ose.yml

Verify the change from the above command by confirming that the container yaml file now looks something like this. Note that the 'expose:' line and all of its subsequent lines are commented-out: 

[root@osestaging1 discourse]# grep -C4 expose /var/discourse/containers/discourse_ose.yml
## Uncomment these two lines if you wish to add Lets Encrypt (https)
  #- "templates/web.ssl.template.yml"
  #- "templates/web.letsencrypt.ssl.template.yml"

## which TCP/IP ports should this container expose?
## If you want Discourse to share a port with another webserver like Apache or nginx,
## see https://meta.discourse.org/t/17247 for details
#expose:
#  - "80:80"   # http
#  - "443:443" # https

params:
[root@osestaging1 discourse]#

Nginx mod_security

In our other sites hosted on this server, we have a nginx -> varnish -> apache architecture. While I'd like to mimic this architecture for all our sites, it's important to note a few things about Apache, Nginx, mod_security, and Discourse that elucidate why we shouldn't do that.

  1. There's a package in the yum repos for adding mod_security to apache. There is no package for adding mod_security to Nginx. Adding mod_security to Nginx requires compiling Nginx from source
  2. Discourse is heavily tied to Nginx. It appears that nobody has ever run Discourse on Apache, and doing so would be non-trivial. Moreover, our custom Apache vhost config would likely break in future versions of Discourse [3]
  3. Putting apache as a reverse proxy in-front of Discourse could add a significant performance issues because of the way Apache handles long polling, which the Discourse message bus uses [4] [5] [6]
  4. The Discourse install process already compiles Nginx from source so that it can add the brotli module to nginx [7]

Therefore, I think it makes sense to cut apache out of the architecture for our Discourse install entirely. If we're already forced to compile nginx from source, we might as well just update their install-nginx script and configure mod_security in nginx instead of apache. Then our architecture becomes nginx -> varnish -> nginx.

First, execute the following commands as root to update the install-nginx script with the logic for installing the depends on our docker container and compiling nginx with mod_security. 

cd /var/discourse/image/base
cp install-nginx install-nginx.`date "+%Y%m%d_%H%M%S"`.orig

# add a block to checkout the the modsecurity nginx module just before downloading the nginx source
grep 'ModSecurity' install-nginx || sed -i 's%\(curl.*nginx\.org/download.*\)%# mod_security --maltfield\napt-get install -y libmodsecurity-dev modsecurity-crs\ncd /tmp\ngit clone --depth 1 https://github.com/SpiderLabs/ModSecurity-nginx.git\n\n\1%' install-nginx

# update the configure line to include the ModSecurity module checked-out above
sed -i '/ModSecurity/! s%^[^#]*./configure \(.*nginx.*\)%#./configure \1\n./configure \1 --add-module=/tmp/ModSecurity-nginx%' install-nginx

# add a line to cleanup section
grep 'rm -fr /tmp/ModSecurity-nginx' install-nginx || sed -i 's%\(rm -fr.*/tmp/nginx.*\)%rm -fr /tmp/ModSecurity-nginx\n\1%' install-nginx

The above commands were carefully crafted to be idempotent and robust so that they will still work on future versions of the install-nginx script, but it's possible that they will break in the future. For reference, here is the resulting file.

Please verify the change from the above commands by confirming that your new file looks something like this. Note the addition of the 'mod-security' block and the changed './configure' line. 

[root@osestaging1 base]# cat /var/discourse/image/base/install-nginx
#!/bin/bash
set -e
VERSION=1.17.4
cd /tmp

apt install -y autoconf  


git clone https://github.com/bagder/libbrotli
cd libbrotli
./autogen.sh
./configure
make install

cd /tmp


# this is the reason we are compiling by hand...
git clone https://github.com/google/ngx_brotli.git

# mod_security --maltfield
apt-get install -y libmodsecurity-dev modsecurity-crs
cd /tmp
git clone --depth 1 https://github.com/SpiderLabs/ModSecurity-nginx.git

curl -O https://nginx.org/download/nginx-$VERSION.tar.gz
tar zxf nginx-$VERSION.tar.gz
cd nginx-$VERSION

# so we get nginx user and so on
apt install -y nginx libpcre3 libpcre3-dev zlib1g zlib1g-dev
# we don't want to accidentally upgrade nginx and undo our work
apt-mark hold nginx

# now ngx_brotli has brotli as a submodule
cd /tmp/ngx_brotli && git submodule update --init && cd /tmp/nginx-$VERSION

# ignoring depracations with -Wno-deprecated-declarations while we wait for this https://github.com/google/ngx_brotli/issues/39#issuecomment-254093378
#./configure --with-cc-opt='-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -Wno-deprecated-declarations' --with-ld-opt='-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-ipv6 --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_addition_module --with-http_dav_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_v2_module --with-http_sub_module --with-stream --with-stream_ssl_module --with-mail --with-mail_ssl_module --with-threads --add-module=/tmp/ngx_brotli
./configure --with-cc-opt='-g -O2 -fPIE -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -Wno-deprecated-declarations' --with-ld-opt='-Wl,-Bsymbolic-functions -fPIE -pie -Wl,-z,relro -Wl,-z,now' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-ipv6 --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_addition_module --with-http_dav_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_v2_module --with-http_sub_module --with-stream --with-stream_ssl_module --with-mail --with-mail_ssl_module --with-threads --add-module=/tmp/ngx_brotli --add-module=/tmp/ModSecurity-nginx

make install

mv /usr/share/nginx/sbin/nginx /usr/sbin

cd /
rm -fr /tmp/ModSecurity-nginx
rm -fr /tmp/nginx
rm -fr /tmp/libbrotli
rm -fr /tmp/ngx_brotli
rm -fr /etc/nginx/modules-enabled/*
[root@osestaging1 base]#

Though unintuitive, Discourse's launcher rebuild script won't actually use these local files in image/base/*, including the install-nginx script modified above. To make sure that our Discourse docker container users a docker image with the nginx changes made above, we have to explicitly specify the image in the hard-coded image variable of the launcher script. This, sadly, is not documented anywhere by the Discourse project, and I only discovered this solution after much trial-and-error.

Execute the following commands as root to change the 'image' variable in the Discourse 'launcher' script. 

# replace the line "image="discourse/base:<version>" with 'image="discourse_ose"'
grep 'discourse_ose' /var/discourse/launcher || sed --in-place=.`date "+%Y%m%d_%H%M%S"` '/base_image/! s%^\(\s*\)image=\(.*\)$%#\1image=\2\n\1image="discourse_ose"%' /var/discourse/launcher

Verify the change from the above command by confirming that the launcher script now looks something like this. Note the commented-out 'image=' line and its replacement below it. 

[root@osestaging1 discourse]# grep 'image=' /var/discourse/launcher
user_run_image=""
    user_run_image="$2"
#image="discourse/base:2.0.20200220-2221"
image="discourse_ose"
  run_image=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
    run_image=$user_run_image
    run_image="$local_discourse/$config"
  base_image=`cat $config_file | $docker_path run $user_args --rm -i -a stdin -a stdout $image ruby -e \
    image=$base_image
[root@osestaging1 discourse]#

And now we must build the 'discourse_ose' docker image, which will execute the updated install-nginx script and then become available to the launcher script above. This image build will take 5 minutes to 1 hour to complete.

Execute the following command as root to build the custom Discourse docker image: 

time nice docker build --tag 'discourse_ose' /var/discourse/image/base/

Next we create a new yaml template to update the relevant nginx configuration files when bootstrapping the environment.

Execute the following commands as root to create the 'web.modsecurity.template.yml' file. 

cat << EOF > /var/discourse/templates/web.modsecurity.template.yml
run:
  - exec:
     cmd:
       - sudo apt-get update
       - sudo apt-get install -y modsecurity-crs
       - cp /etc/modsecurity/modsecurity.conf-recommended /etc/modsecurity/modsecurity.conf
       - sed -i 's/SecRuleEngine DetectionOnly/SecRuleEngine On/' /etc/modsecurity/modsecurity.conf
       - sed -i 's^\(\s*\)[^#]*SecRequestBodyInMemoryLimit\(.*\)^\1#SecRequestBodyInMemoryLimit\2^' /etc/modsecurity/modsecurity.conf
       - sed -i '/nginx/! s%^\(\s*\)[^#]*SecAuditLog \(.*\)%#\1SecAuditLog \2\n\1SecAuditLog /var/log/nginx/modsec_audit.log%' /etc/modsecurity/modsecurity.conf

  - file:
     path: /etc/nginx/conf.d/modsecurity.include
     contents: |
        ################################################################################
        # File:    modsecurity.include
        # Version: 0.1
        # Purpose: Defines mod_security rules for the discourse vhost
        #          This should be included in the server{} blocks nginx vhosts.
        # Author:  Michael Altfield <michael@opensourceecology.org>
        # Created: 2019-11-12
        # Updated: 2019-11-12
        ################################################################################
        Include "/etc/modsecurity/modsecurity.conf"
        
        # OWASP Core Rule Set, installed from the 'modsecurity-crs' package in debian
        Include /etc/modsecurity/crs/crs-setup.conf
        Include /usr/share/modsecurity-crs/rules/*.conf

  - replace:
     filename: "/etc/nginx/conf.d/discourse.conf"
     from: /server.+{/
     to: |
       server {
         modsecurity on;
         modsecurity_rules_file /etc/nginx/conf.d/modsecurity.include;

EOF

Execute the following command as root to add the above-created template to our Discourse docker container yaml file's templates list: 

grep 'templates/web.modsecurity.template.yml' containers/discourse_ose.yml || sed -i 's%^\([^#].*templates/web.socketed.template.yml.*\)$%\1\n  - "templates/web.modsecurity.template.yml"%' containers/discourse_ose.yml

Verify the change from the above command by confirming that the containers/discourse_ose.yml file looks something like this. Note the addition of the templates/web.modsecurity.template.yml line. 

[root@osestaging1 discourse]#  grep -A10 templates containers/discourse_ose.yml
templates:
  - "templates/web.socketed.template.yml"
  - "templates/web.modsecurity.template.yml"
  - "templates/postgres.template.yml"
  - "templates/redis.template.yml"
  - "templates/web.template.yml"
  - "templates/web.ratelimited.template.yml"
## Uncomment these two lines if you wish to add Lets Encrypt (https)
  #- "templates/web.ssl.template.yml"
  #- "templates/web.letsencrypt.ssl.template.yml"

## which TCP/IP ports should this container expose?
## If you want Discourse to share a port with another webserver like Apache or nginx,
## see https://meta.discourse.org/t/17247 for details
#expose:
#  - "80:80"   # http
#  - "443:443" # https

params:
  db_default_text_search_config: "pg_catalog.english"
[root@osestaging1 discourse]#

iptables

Discourse will run fine with its container having literally no internet access. This is because the communication in/out of the Discourse docker container is done via an nginx reverse proxy on the docker host through a unix socket file on the Discourse docker container.

However, the docker container is a whole OS on its own, including its own apt packages. Therefore, it's critical that the docker container running Discourse maintain security patches for its OS via Debian's unattended-upgrades. 

* https://wiki.debian.org/UnattendedUpgrades
* https://github.com/discourse/discourse/blob/master/docs/INSTALL-cloud.md#post-install-maintenance

Therefore, rather than blocking all internet traffic from the Discourse container, it's better to use iptables on the docker host to setup a firewall similar to how we set it up on our other servers (blocking the web server from initiating OUTbound connections). Note that this is necessarily done inside the container so we can create OUTPUT rules that block on a per-user basis, which cannot be done from the docker host. This is critical to prevent nginx/ruby/etc from initiating outbound connections. Indeed, web servers should only be able to respond to requests.

Unfortunately, being root in the default Discourse docker container is actually not sufficient to edit iptables rules. You'll still get permission denied errors. To fix this, first we must add the NET_ADMIN capability to the Discourse docker container spawned by the launcher script. The most robust way to add the NET_ADMIN capability to the Discourse docker container is to update your container’s yaml file to include the necessary argument to the docker run ... /sbin/boot command via the docker_args yaml string:

Execute this as root to update the container's yaml file: 

grep 'NET_ADMIN' /var/discourse/containers/discourse_ose.yml || sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^templates:$%docker_args: "--cap-add NET_ADMIN"\n\ntemplates:%' /var/discourse/containers/discourse_ose.yml

Verify the change from the above command by confirming that your file now looks something like this. Note the addition of the 'docker_args:' line. 

[root@osestaging1 discourse]# grep -C2 'templates:' /var/discourse/containers/discourse_ose.yml
docker_args: "--cap-add NET_ADMIN"

templates:
  - "templates/web.socketed.template.yml"
  - "templates/web.modsecurity.template.yml"
[root@osestaging1 discourse]#

The above change defined --cap-add NET_ADMIN as an extra argument to be passed to the docker run ... /sbin/boot command executed by launcher script's run_start() function via the $user_args variable: 

* https://github.com/discourse/discourse_docker/blob/87fd7172af8f2848d5118fdebada646c5996821b/launcher#L631-L633

run_start() {
...
     $docker_path run --shm-size=512m $links $attach_on_run $restart_policy "${env[@]}" "${labels[@]}" -h "$hostname" 
        -e DOCKER_HOST_IP="$docker_ip" --name $config -t "${ports[@]}" $volumes $mac_address $user_args \
        $run_image $boot_command

   )
   exit 0

}

Now we add a template for setting up iptables in the docker container's runit boot scripts. 

cat << EOF > /var/discourse/templates/iptables.template.yml
run:
  - file:
     path: /etc/runit/1.d/01-iptables
     chmod: "+x"
     contents: |
        #!/bin/bash
        ################################################################################
        # File:    /etc/runit/1.d/01-iptables
        # Version: 0.2
        # Purpose: installs & locks-down iptables
        # Author:  Michael Altfield <michael@opensourceecology.org>
        # Created: 2019-11-26
        # Updated: 2019-12-17
        ################################################################################
        sudo apt-get update
        sudo apt-get install -y iptables 
        sudo iptables -A INPUT -i lo -j ACCEPT
        sudo iptables -A INPUT -s 127.0.0.1/32 -j DROP
        sudo iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
        sudo iptables -A INPUT -j DROP
        sudo iptables -A OUTPUT -s 127.0.0.1/32 -d 127.0.0.1/32 -j ACCEPT
        sudo iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
        sudo iptables -A OUTPUT -m owner --uid-owner 0 -j ACCEPT
        sudo iptables -A OUTPUT -m owner --uid-owner 100 -j ACCEPT
        sudo iptables -A OUTPUT -j DROP
        sudo ip6tables -A INPUT -i lo -j ACCEPT
        sudo ip6tables -A INPUT -s ::1/128 -j DROP
        sudo ip6tables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
        sudo ip6tables -A INPUT -j DROP
        sudo ip6tables -A OUTPUT -s ::1/128 -d ::1/128 -j ACCEPT
        sudo ip6tables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
        sudo ip6tables -A OUTPUT -m owner --uid-owner 0 -j ACCEPT
        sudo ip6tables -A OUTPUT -m owner --uid-owner 100 -j ACCEPT
        sudo ip6tables -A OUTPUT -j DROP

EOF

And, finally, execute the following command as root to add the above-created template to our container yaml file's template list: 

grep 'templates/iptables.template.yml' /var/discourse/containers/discourse_ose.yml || sed --in-place=.`date "+%Y%m%d_%H%M%S"` 's%^templates:$%templates:\n  - "templates/iptables.template.yml"%' /var/discourse/containers/discourse_ose.yml

Verify the change from the above command by confirming that your containers/discourse_ose.yml file looks something like this. Note the addition of the 'templates/iptables.template.yml' line. 

[root@osestaging1 discourse]# grep -C2 'templates:' /var/discourse/containers/discourse_ose.yml
docker_args: "--cap-add NET_ADMIN"

templates:
  - "templates/iptables.template.yml"
  - "templates/web.socketed.template.yml"
[root@osestaging1 discourse]#

discourse.opensourcecology.org DNS

Add 'discourse.opensourceecology.org' to the list of domain names defined for our VPN IP Address in /etc/hosts on the staging server.

In production, this will mean actually adding A & AAAA DNS entries for 'discourse' to point to our production server.

Nginx Vhost Config

Create the following nginx vhost config file to proxy connections sent to 'discourse.opensourceecology.org' to the unix socket file created by Discourse. Note that this file exists on the docker server that runs the Discourse container, and it controls _that_ nginx server--which is distinct from the nginx server that runs _inside_ the Discourse docker container.

Execute the following commands as root to create the '/etc/nginx/conf.d/discourse.opensourceecology.org.conf' file. 

cat << EOF > /etc/nginx/conf.d/discourse.opensourceecology.org.conf
################################################################################
# File:    discourse.opensourceecology.org.conf
# Version: 0.1
# Purpose: Internet-listening web server for truncating https, basic DOS
#          protection, and passing to varnish cache (varnish then passes to
#          apache)
# Author:  Michael Altfield <michael@opensourceecology.org>
# Created: 2019-11-07
# Updated: 2019-11-07
################################################################################

# this whole site is a subdomain, so the below block for redirecting a naked
# domain does not apply here
#server {
#       # redirect the naked domain to 'www'
#       #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
#   #                   '$status $body_bytes_sent "$http_referer" '
#   #                   '"$http_user_agent" "$http_x_forwarded_for"';
#       #access_log /var/log/nginx/www.opensourceecology.org/access.log main;
#       #error_log /var/log/nginx/www.opensourceecology.org/error.log main;
#   include conf.d/secure.include;
#   include conf.d/ssl.opensourceecology.org.include;
#   listen 10.241.189.11:443;
#       server_name opensourceecology.org;
#       return 301 https://www.opensourceecology.org$uri;
#
#}

server {

		access_log /var/log/nginx/discourse.opensourceecology.org/access.log main;
		error_log /var/log/nginx/discourse.opensourceecology.org/error.log;

   include conf.d/secure.include;
   include conf.d/ssl.opensourceecology.org.include;
   #include conf.d/ssl.openbuildinginstitute.org.include;

   listen 10.241.189.11:443;
   #listen [2a01:4f8:172:209e::2]:443;

   server_name discourse.opensourceecology.org;

		#############
		# SITE_DOWN #
		#############
		# uncomment this block && restart nginx prior to apache work to display the
		# "SITE DOWN" webpage for our clients

#       root /var/www/html/SITE_DOWN/htdocs/;
#   index index.html index.htm; 
#
#       # force all requests to load exactly this page
#       location / {
#               try_files $uri /index.html;
#       }

		###################
		# SEND TO VARNISH #
		###################

#   location / {
#      proxy_pass http://127.0.0.1:6081;
#      proxy_set_header X-Real-IP $remote_addr;
#      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
#      proxy_set_header X-Forwarded-Proto https;
#      proxy_set_header X-Forwarded-Port 443;
#      proxy_set_header Host $host;
#   }

		##################
		# SEND TO DOCKER #
		##################

	location / {
		proxy_pass http://unix:/var/discourse/shared/standalone/nginx.http.sock:;
		proxy_set_header Host $http_host;
		proxy_http_version 1.1; 
		proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
		proxy_set_header X-Forwarded-Proto https;
		proxy_set_header X-Real-IP $remote_addr;
	}

}
EOF

Varnish

TODO: actually include varnish 

* https://meta.discourse.org/t/discourse-purge-cache-method-on-content-changes/132917

Backups

Add this block to /root/backups/backup.sh (TODO: test this) 

#############
# DISCOURSE #
#############

# cleanup old backups
$NICE $RM -rf /var/discourse/shared/standalone/backups/default/*.tar.gz
time $NICE $DOCKER exec discourse_ose discourse backup
$NICE $MV /var/discourse/shared/standalone/backups/default/*.tar.gz "${backupDirPath}/${archiveDirName}/discourse_ose/"

...

#########
# FILES #
#########

# /var/discourse
echo -e "\tINFO: /var/discourse"
$MKDIR "${backupDirPath}/${archiveDirName}/discourse_ose"
time $NICE $TAR --exclude "/var/discourse/shared/standalone/postgres_data" --exclude "/var/discourse/shared/standalone/postgres_data/uploads" --exclude "/var/discourse/shared/standalone/backups" -czf ${backupDirPath}/${archiveDirName}/discourse_ose/discourse_ose.${stamp}.tar.gz /var/discourse/*

SSL Cert

TODO: update the certbot cron script to add a Subject Alt Name for discourse.opensourceecology.org

Import Vanilla Forums

TODO: attempt to import our old forum's data into Discourse.

Docker image cleanup cron

A common pitfall when running docker in production is that the images build up over time, eventually filling the disk and breaking the server.

Execute the commands below as root to add a script and corresponding cron job & log dir for pruning docker images to prevent disk-fill: 

cat << EOF > /usr/local/bin/docker-purge.sh
#!/bin/bash
set -x
################################################################################
# Author:  Michael Altfield <michael at opensourceecology dot org>
# Created: 2020-03-08
# Updated: 2020-03-08
# Version: 0.1
# Purpose: Cleanup docker garbage to prevent disk fill issues
################################################################################

############
# SETTINGS #
############

NICE='/bin/nice'
DOCKER='/bin/docker'
DATE='/bin/date'

##########
# HEADER #
##########

stamp=`${DATE} -u +%Y%m%d_%H%M%S`
echo "================================================================================"
echo "INFO: Beginning docker pruning on ${stamp}"

###################
# DOCKER COMMANDS #
###################

# automatically clean unused container and images that are >= 4 weeks old
time ${NICE} ${DOCKER} container prune --force --filter until=672h
time ${NICE} ${DOCKER} image prune --force --all --filter until=672h
time ${NICE} ${DOCKER} system prune --force --all --filter until=672h

# exit cleanly
exit 0
EOF
chmod +x /usr/local/bin/docker-purge.sh
mkdir /var/log/docker
cat << EOF > /etc/cron.d/docker-prune
40 07 * * * root time /bin/nice /usr/local/bin/docker-purge.sh &>> /var/log/docker/prune.log
EOF

Start Discourse

Execute the following command TODO

TODO

Congratulations! Docker should now be fully installed.

Updating Discoruse

This section will describe how to update the Discourse software

Discourse Versions

First, a note about Discourse releases: Discourse maintains a "stable" release, but they don't actually backport bug patches to their stable releases like one would expect. There's no LTS (or STS!) for Discourse stable releases.

They only fix bugs in future beta releases (which will also include new commits that may break more things). Therefore, the default branch for production is "beta" releases, and they urge their customers not to use "stable." I honestly think this is a terrible idea, especially for a small org like OSE without any full-time ops staff to constantly update our prod apps. 

* https://github.com/discourse/discourse/releases

IMHO, the takeaway to this is that updates should be done to Discourse very carefully and with through testing in staging before taking a backup and following the identical procedure on production.

Check for Updates

Discourse updates often, and it will tell you to update the app (requiring downtime) even if there's 1 (untested?) commit to their discourse github repository 

* https://github.com/discourse/discourse/

Step 0: Trigger Backup Scripts for System-Wide backup

For good measure, trigger a backup of the entire system's database & files: 

sudo su -
time sudo /bin/nice /root/backups/backup.sh &>> /var/log/backups/backup.log
exit

When finished, list the backup files in our Backblaze B2 server backups bucket to verify that the whole system backup was successful before proceeding 

source /root/backups/backup.settings
$SUDO -u ${b2UserName} $B2 ls ${B2_BUCKET_NAME}

Step 1: Set variables

Type these commands to set some variables, which will be used by the commands in the sections below. Replace 'www.opensourceecology.org' with the corresponding directory for the wp site you're updating. 

sudo su -
export vhostDir="/var/discourse/"
export stamp=`date +%Y%m%d_%T`
export tmpDir="/var/tmp/discourseUpgrade.${stamp}"

# verify
echo "${vhostDir}"
echo "${stamp}"
echo "${tmpDir}"
ls -lah "${vhostDir}"

Step 2: Make Vhost-specific backups

The backups made in the previous step are huge. Because it's easier to work with vhost-specific backups, let's make a redundant copy available in /var/tmp/: 

mkdir "${tmpDir}"
chown root:root "${tmpDir}"
chmod 0700 "${tmpDir}"
pushd "${tmpDir}"

# discourse backup (db & uploaded files only)
nice rm -rf /var/discourse/shared/standalone/backups/default/*.tar.gz
time nice docker exec discourse_ose discourse backup
nice mv /var/discourse/shared/standalone/backups/default/*.tar.gz ${tmpDir}/

# files backup (all discourse files)
time nice tar --exclude "${vhostDir}/shared/standalone/postgres_data" --exclude "${vhostDir}/shared/standalone/postgres_data/uploads" --exclude "${vhostDir}/shared/standalone/backups" -czf ${tmpDir}/discourse_files.${stamp}.tar.gz /var/discourse/*

popd

Step 3: Update git

We've made some OSE-specific changes to the files in /var/discourse that conflict with the upstream git repo, so let's move those out of the way before updating. After the git pull, we'll update them again.

First execute the commands shown in the example below as root to get a list of all the files that have been modified locally. 

[root@osestaging1 /]# pushd /var/discourse
/var/discourse /
[root@osestaging1 discourse]# git status --short | grep -E '^\s*M'
 M image/base/install-nginx
 M launcher
[root@osestaging1 discourse]# popd
/
[root@osestaging1 /]#

In the example above, we see that the '/var/discourse/launcher' script and '/var/discourse/image/base/install-nginx' script have both been modified in our custom OSE install. Now let's move those two files out of the way so we can do a clean `git pull` after.

Execute the following commands as root. If there were more than just the two files listed above that were modified, then you should update this documentation to reflect the necessary changes. 

export vhostDir="/var/discourse/"
stamp=`date "+%Y%m%d_%H%M%S"`

# launcher
mv "${vhostDir}/launcher" "${vhostDir}/launcher.${stamp}"
git checkout "${vhostDir}/launcher"

# install-nginx
mv "${vhostDir}/image/base/install-nginx" "${vhostDir}/image/base/install-nginx.${stamp}"
git checkout "${vhostDir}/image/base/install-nginx"

Now sync to the upstream repo 

pushd "${vhostDir}"
git pull origin master
popd

Before proceeding, let's get a diff of the changes so we can understand what may have changed upstream, which might break our commands in our OSE Discourse install guide 

diff "${vhostDir}/image/base/install-nginx.${stamp}" "${vhostDir}/image/base/install-nginx"
diff "${vhostDir}/launcher.${stamp}" "${vhostDir}/launcher"

Write down the output from the above commands in your log; you may need it to debug later.

Next, to re-apply the changes to the 'install-nginx' script and "launcher' script, see the following relevant section for a list of the necessary commands:

  1. #Nginx_mod_security

See also https://meta.discourse.org/t/how-do-i-manually-update-discourse-and-docker-image-to-latest/23325

Step 4: Build Discourse docker image with OSE modifications

Now we must rebuild the upstream Discourse Docker image with our OSE-specific modifications, such as giving nginx mod_security support. 

pushd "${vhostDir}/image/base"

# force a fresh build (no-cache) so the `git pull` lines will trigger
# note this will take a *ridiculously* long time; the Discourse team compiles many packages from source :(
time nice docker build --no-cache --network=host --tag 'discourse_ose' /var/discourse/image/base/

popd

Step 5: Rebuild the app

time nice ${vhostDir}/launcher rebuild discourse_ose

Looking Forward

This section will outline possible changes to be made to the Docker install/config in the future

Moving DBs outside docker

It's worthwhile to consider moving the redis and postgresql components of Discourse outside of the docker container [8]

MJ Feb 2019 Review

  • Legend: Check.png = exists, Check.pngCheck.png = good, Check.pngCheck.pngCheck.png = great
  • Check.pngQ&A plugin appears to be adequate, but does not have downvotes. Downvotes are important, as a knowledgeable person should ideally be able to downsize bull****. This is important for collaborative learning - and should be developed to approach the usefulness of Stack Exchange and Reddit. Would need to put development time into this.
  • Check.pngCheck.pngCheck.pngRating - appears excellent - [1]
  • Check.pngCheck.pngCheck.pngCommenting plugin - excellent, up with Disqus. [2]
  • Check.pngCheck.pngCheck.pngBug Tracking - a simple wiki/Discourse hack can be done by a Bugtracking or Known Bugs category on the wiki, and embedding a thread on that bug from Discourse, so discussion can happen, and when resolved, thread can be closed. We'd have to see in practice how this looks. That is the simplest way to go without installing yet another pieces of software, and using Discourse and Wiki hold most of the weight, the rest being Wordpress.

Cons

  • Free to try rather than really free? See last con at [3]

OSE Use Case

  • The generic OSE use case for transparency is using the Wiki for embedding all kinds of content, where the wiki is a proven and scalable tool for collaborative development - and a core tool in OSE's usage. With this said, it is useful to have various forms of content embedded in the wiki, so that we don't have to use many different platforms for different functions: we can just embed content from other common platforms. The intent is modular design where content can be reused and mixed throughout OSE's web presence.
  1. Embed individual Discourse threads on wiki pages. This way we upgrade content from wiki pages to live discussion - where content for discussion can be edited right in the wiki page. The intent of this is to improve the use of the Wiki as a development platform so that the wiki is more intuitive. See embed of thread example - [4]. This must allow any single thread from Discourse to be embedded.
  2. Rating of a service or product - in an open source franchise, products/services of collaborators can be rated. A simple tool like the wiki can have a rating feature - without having to use any other software. This is yet another way to make the wiki more functional and user-friendly. See example - [5]
  3. Upvoting - no evidence of Discourse serving this function well compared to Askbot. By upvoting, we mean simply that all the content remains visible, and a single solution is not marked. This allows users to pick nuggets from different answers - while allowing bulk filtering to occur before looking at the answer. From the OSE perspective, marking a question as resolved is not inclusive or abundant. What if someone else has a better solution? It may be that Discourse can be modified to do upvoting readily, or can simulate this function well - but we would have to see in practice if this is feasible.

2018-09 Review

In 2018-09, I (Michael Altfield) had just learned about Discourse as I was working on the phplist project. phplist's forums use Discourse. At the same time, Alex Au recommended to Marcin that we setup a replacement forum using Discourse.

Pros

  1. Very pleasant interface
  2. Very nice functionality ootb. Badges, user trust system for easy moderation, climbing ranks, love, at-calls (@), etc -- co-founder Jeff Atwood also founded Stack Exchange, so expect similar functionality
  3. Very popular. Many, many forums have switched to Discourse over the past several years
  4. Great selection of plugins & integrations (though no decent db/index for searching them) https://meta.discourse.org/c/plugin https://github.com/discourse
    1. ie: replace wordpress comments with a discourse thread. This may or may not be good.
      1. Example wordpress blog post: https://blog.discourse.org/2018/06/understanding-discourse-trust-levels/
      2. Corresponding discourse thread for the comments to the above post: https://meta.discourse.org/t/wp-discourse-dysfunctional-shows-only-start-the-discussion-at/36016
  5. Looks like we can import our content from Vanila https://meta.discourse.org/t/how-to-migrate-from-vanilla-to-discourse/27273
  6. Well-funded org that hosts their project (think wordpress.com) for many of their customers. The good here is that Discorse can pay a salary to devs, unlike many open source projects. But it's worth nothing that people choose to pay for hosting probably because it's Ruby on Rails, and a PIA to self-host.
  7. While not officially supported, it looks like users have setup Discourse behind varnish 4 [9]

Cons

  1. Ruby on rails
  2. They openly state that they're hard to install, and therefore _only_ support installation via a docker container [10]
  3. I'm seriously worried about the security of a project that thinks it's acceptable to use wget -qO- https://get.docker.com/ | sh as a step in their install guide [11]
  4. Discourse explicitly states that they only support newer devices. I'm concerned that means that we may make our content inaccessible to, say, that 6-year-old desktop running windows xp in the machine shop. Indeed, discourse only supports IE 11+, which came with Windows 8.1 in 2013--5 years ago. [12]
  5. If javascript is disabled, the site is read-only. JS is a requirement for posting, replying, etc. But because Discourse also functions as a mailing list, JS-free users can still contribute content in a limited way by replying to threads via email [13]

Neutral

  1. Project has been around for 5 years (initial release in 2013) https://en.wikipedia.org/wiki/Discourse_%28software%29

Noteable sites using Discourse

  1. Ubuntu https://discourse.ubuntu.com/
  2. Phplist https://discuss.phplist.org/
  3. Whonix https://forums.whonix.org/
  4. Manjaro https://forum.manjaro.org

See Also

References

  1. ↑ https://github.com/docker/for-linux/issues/849
  2. ↑ https://meta.discourse.org/t/running-other-websites-on-the-same-machine-as-discourse/17247
  3. ↑ https://meta.discourse.org/t/how-to-run-discourse-in-apache-vhost-not-nginx/133112/11
  4. ↑ https://meta.discourse.org/t/howto-setup-discourse-with-lets-encrypt-and-apache-ssl/46139
  5. ↑ https://stackoverflow.com/questions/14157515/will-apache-2s-mod-proxy-wait-and-occupy-a-worker-when-long-polling
  6. ↑ https://github.com/SamSaffron/message_bus
  7. ↑ https://github.com/discourse/discourse_docker/blob/416467f6ead98f82342e8a926dc6e06f36dfbd56/image/base/install-nginx#L18
  8. ↑ https://meta.discourse.org/t/performance-scaling-and-ha-requirements/60098/8
  9. ↑ https://meta.discourse.org/t/discourse-behind-varnish/4864/10
  10. ↑ https://github.com/discourse/discourse/blob/master/docs/INSTALL.md#why-do-you-only-officially-support-docker
  11. ↑ https://github.com/discourse/discourse/blob/master/docs/INSTALL-cloud.md#install-docker--git
  12. ↑ https://github.com/discourse/discourse#requirements
  13. ↑ https://forums.whonix.org/t/turn-off-javascript-for-forums/1692/2

Links

  1. Discourse Install Log
  2. https://docs.discourse.org- API Docs only (not very useful)
  3. https://meta.discourse.org/c/10-howto - "howto" tagged topics on meta.discourse.org
  4. https://meta.discourse.org/c/howto/faq/4 - Discourse FAQ
  5. https://meta.discourse.org/t/advanced-troubleshooting-with-docker/15927
  6. https://meta.discourse.org/t/where-are-all-the-discourse-logs/58022
  7. https://meta.discourse.org/t/discourse-moderation-guide/63116
  9. Civilized Discourse Construction Kit - positively biased post about Discourse - [6]
  10. https://www.slant.co/options/2789/~discourse-review
  11. https://forums.whonix.org/t/change-whonix-forum-software-to-discourse/1181
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