Awesome

dlss-capistrano

This gem provides Capistrano deployment tasks used by Stanford Libraries' Digital Library Systems and Services group.

Necessary Setup

To start, we recommend an SSH configuration like the one described in the DeveloperPlaybook, since it has sensible defaults for Kerberos authentication and multi-factor authentication (using ProxyJump and ControlMaster, etc.).

To get dlss-capistrano tasks running via an existing SSH control master socket, you need to opt-in by setting the environment variable USE_CAPISTRANO_CONTROLMASTER=true (in e.g. your ~/.zshenv file or similar for your particular shell).

If your SSH client configuration (~/.ssh/config) uses values other than the defaults for CONTROLMASTER_HOST (which maps to the ProxyJump directive, and defaults to dlss-jump) or CONTROLMASTER_SOCKET (which maps to the ControlPath directive, and defaults to ~/.ssh/%r@%h:%p), you'll want to set these environment variables locally to the values you use (in e.g. your ~/.zshenv file or similar for your particular shell). Otherwise, the gem will fail to connect to the appropriate jump host and/or won't be able to properly check the status of the control master process.

Included Tasks

Remote Execution

Sometimes you want to execute a command on all boxes in a given environment, and dlss-capistrano's got your back:

$ cap qa remote_execute["ps -ef | grep rolling | grep -v grep"]
00:00 remote_execute
      ps -ef | grep rolling | grep -v grep
      ps -ef | grep rolling | grep -v grep
      dor-indexing-app-qa-a.stanford.edu:
dor_ind+  9159     1 20 Feb18 ?        14:15:03 rolling index
      dor-indexing-app-qa-b.stanford.edu:
dor_ind+ 29689     1 20 Feb18 ?        14:24:53 rolling index

Sidekiq symlink

Every time the version of Sidekiq or Ruby changes, a corresponding Puppet PR must be made in order to update the XSendFilePath that allows Apache to access the bundled Sidekiq gem's assets. dlss-capistrano provides a hook to create a symlink to the bundled Sidekiq to avoid having to do this:

set :bundled_sidekiq_symlink, true # false is the default value
set :bundled_sidekiq_roles, [:app] # this is the default value

Set this in config/deploy.rb to automate the symlink creation, and then use XSendFilePath /path/to/my/app/shared/bundled_sidekiq/web/assets in Apache configuration (in Puppet).

Status checking

NOTE: Requires that curl is installed on each server host the check is run on.

Use cap ENV check_status to hit the (e.g., okcomputer-based) status endpoint of your application. This is especially valuable with hosts that cannot be directly checked due to firewall rules.

By default, these checks run against all nodes with the :web role and hit the /status/all endpoint. These can be configured in config/deploy.rb (or config/deploy/{ENV}.rb if you need environment-specific variation):

set :check_status_roles, [:my_status_check_web_role]
set :check_status_path, '/my/status/check/endpoint'

Update global strscan gem

This insures the global version of strscan matches the version specified in the bundle.

To skip this step provide SKIP_UPDATE_STRSCAN=1

SSH

cap ENV ssh establishes an SSH connection to the host running in ENV environment, and changes into the current deployment directory

SSH Connection Checking

cap ENV ssh_check establishes an SSH connection to all app servers running in ENV environment and prints environment information to confirm the connection was made. This is used by sdr-deploy to check SSH connections can be made in bulk before proceeding with a mass deploy.

Display Revision (and branches)

cap ENV deployed_branch displays the currently deployed revision (commit ID) and any branches containing the revision for each server in ENV.

Sidekiq via systemd

cap ENV sidekiq_systemd:{quiet,stop,start,restart}: quiets, stops, starts, restarts Sidekiq via systemd.

These tasks are intended to replace those provided by capistrano-sidekiq gem, which has assumptions about systemd that do not apply to our deployed environments.

Sneakers via systemd

cap ENV sneakers_systemd:{stop,start,restart}: stops, starts, restarts Sneakers via systemd.

Racecar via systemd

cap ENV racecar_systemd:{stop,start,restart}: stops, starts, restarts Racecar via systemd.

Capistrano role

The sidekiq_systemd tasks assume a Capistrano role of :app. If your application uses a different Capistrano role for hosts that run Sidekiq workers, you can configure this in config/deploy.rb, e.g.:

set :sidekiq_systemd_role, :worker

Deployment hooks

The sidekiq_systemd tasks assume you want to hook them into Capistrano deployment on your own. If you want to use the hooks provided by dlss-capistrano, you can opt in via config/deploy.rb:

set :sidekiq_systemd_use_hooks, true

These are the hooks provided if you opt in:

after 'deploy:failed', 'sidekiq_systemd:restart'
after 'deploy:published', 'sidekiq_systemd:start'
after 'deploy:starting', 'sidekiq_systemd:quiet'
after 'deploy:updated', 'sidekiq_systemd:stop'

Assumptions

dlss-capistrano makes the following assumptions about your Ruby project

You are using Capistrano 3+
You use git for source control
The server you deploy to uses rvm, it is installed system-wide, and is the default system ruby
You do not have an .rvmrc checked into git (should be in your .gitignore)
You will not use rvm gemsets on the server you deploy to
Bundler will install specified gems into {your_project_home}/shared/bundle directory

Releasing

To release a new version:

Update the version number in dlss-capistrano.gemspec and commit.
bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.