dlss-capistrano

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

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.

Resque-Pool hot swap (OPTIONAL)

The dlss-capistrano gem provides a set of tasks for managing resque-pool workers when deployed in hot_swap mode. (If you are using resque-pool without hot_swap, we recommend continuing to use the capistrano-resque-pool gem instead of what dlss-capistrano provides.) The tasks are:

$ cap ENV resque:pool:hot_swap # this gracefully replaces the current pool with a new pool
$ cap ENV resque:pool:stop     # this gracefully stops the current pool

By default, these tasks are not provided; instead, they must be explicitly enabled via adding a new require statement to the application's Capfile:

require 'dlss/capistrano/resque_pool'

This is the hook provided if you opt in:

after 'deploy:publishing', 'resque:pool:hot_swap'

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