Module: SSHKitDslRoles

Defined in:

lib/dash/sshkit_with_ext.rb

Instance Method Summary

• #on_roles(roles, hosts:, parallel: true, rolling: false, &block) ⇒ Object

  Execute on hosts grouped by role.

Instance Method Details

#on_roles(roles, hosts:, parallel: true, rolling: false, &block) ⇒ Object

Execute on hosts grouped by role.

Unlike on() which deduplicates hosts, this allows the same host to have multiple concurrent connections when it appears in multiple roles.

Options:

hosts: The hosts to run on (required)
parallel: When true, each role runs in its own thread with separate
        connections. When false, hosts run in parallel but roles on each
        host run sequentially (default: true)
rolling:  When true, each role's own `boot` config paces its hosts through
        the SSHKit runner, so one role can boot serially while its
        siblings still boot in parallel. Only for commands that start
        containers — it would needlessly serialize read-only commands.
        Requires parallel: there is no per-role runner otherwise.

Example:

on_roles(roles) do |host, role|
# deploy role to host
end

# File 'lib/dash/sshkit_with_ext.rb', line 374

def on_roles(roles, hosts:, parallel: true, rolling: false, &block)
  if parallel
    # See CompleteAll#execute: thread-locals do not cross Thread.new.
    timing_entry = DashTimings.current_entry

    threads = roles.filter_map do |role|
      if (role_hosts = role.hosts & hosts).any?
        Thread.new do
          DashTimings.current_entry = timing_entry
          on(role_hosts, rolling ? role.boot_runner_options(role_hosts) : {}) { |host| instance_exec(host, role, &block) }
        rescue StandardError => e
          raise SSHKit::Runner::ExecuteError.new(e), "Exception while executing on #{role}: #{e.message}"
        end
      end
    end

    exceptions = []
    threads.each do |t|
      begin
        t.join
      rescue SSHKit::Runner::ExecuteError => e
        exceptions << e
      end
    end

    if exceptions.one?
      raise exceptions.first
    elsif exceptions.many?
      raise exceptions.first, [ "Exceptions on #{exceptions.count} roles:", exceptions.map(&:message) ].join("\n")
    end
  else
    # Host-first iteration: hosts run in parallel, roles on each host run sequentially
    on(hosts) do |host|
      roles.each do |role|
        instance_exec(host, role, &block) if role.hosts.include?(host.to_s)
      end
    end
  end
end