Add role concern with specialized cmds for job running

lib/mrsk/commands/app.rb

@@ -9,15 +9,18 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
     docker :pull, config.absolute_image
   end
 
-  def run
+  def run(role: :web)
+    role = config.role(role)
+
     docker :run,
       "-d",
       "--restart unless-stopped",
       "--name", config.service_with_version,
       "-e", redact("RAILS_MASTER_KEY=#{config.master_key}"),
-      *config.envs,
-      *config.labels,
-      config.absolute_image
+      *config.env_args,
+      *role.label_args,
+      config.absolute_image,
+      role.cmd
   end
 
   def start
@@ -39,7 +42,7 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
   def exec(*command)
     docker :exec, 
       "-e", redact("RAILS_MASTER_KEY=#{config.master_key}"),
-      *config.envs,
+      *config.env_args,
       config.service_with_version,
       *command
   end

lib/mrsk/configuration.rb

@@ -1,14 +1,21 @@
 require "active_support/ordered_options"
+require "active_support/core_ext/string/inquiry"
 require "erb"
 
 class Mrsk::Configuration
-  delegate :service, :image, :env, :registry, :ssh_user, to: :config, allow_nil: true
+  delegate :service, :image, :servers, :env, :registry, :ssh_user, to: :config, allow_nil: true
 
-  def self.load_file(file)
-    if file.exist?
-      new YAML.load(ERB.new(IO.read(file)).result).symbolize_keys
-    else
-      raise "Configuration file not found in #{file}"
+  class << self
+    def load_file(file)
+      if file.exist?
+        new YAML.load(ERB.new(IO.read(file)).result).symbolize_keys
+      else
+        raise "Configuration file not found in #{file}"
+      end
+    end
+
+    def argumentize(argument, attributes)
+      attributes.flat_map { |k, v| [ argument, "#{k}=#{v}" ] }
     end
   end
 
@@ -17,11 +24,39 @@ class Mrsk::Configuration
     ensure_required_keys_present
   end
 
+
+  def roles
+    @roles ||= role_names.collect { |role_name| Role.new(role_name, config: self) }
+  end
+
+  def role(name)
+    roles.detect { |r| r.name == name.to_s }
+  end
+
   def hosts
-    ENV["HOSTS"] || config.servers
+    hosts =
+      case
+      when ENV["HOSTS"]
+        ENV["HOSTS"].split(",")
+      when ENV["ROLES"]
+        role_names = ENV["ROLES"].split(",")
+        roles.select { |r| role_names.include?(r.name) }.flat_map(&:hosts)
+      else
+        roles.flat_map(&:hosts)
+      end
+
+      if hosts.any?
+        hosts
+      else
+        raise ArgumentError, "No hosts found"
+      end
   end
+
+  def primary_host
+    role(:web).hosts.first
   end
 
+
   def version
     @version ||= ENV["VERSION"] || `git rev-parse HEAD`.strip
   end
@@ -38,18 +73,9 @@ class Mrsk::Configuration
     "#{service}-#{version}"
   end
 
-  def envs
-    parameterize "-e", env if env.present?
-  end
 
-  def labels
-    parameterize "--label", \
-      "service" => service,
-      "traefik.http.routers.#{service}.rule" => "'PathPrefix(`/`)'",
-      "traefik.http.services.#{service}.loadbalancer.healthcheck.path" => "/up",
-      "traefik.http.services.#{service}.loadbalancer.healthcheck.interval" => "1s",
-      "traefik.http.middlewares.#{service}.retry.attempts" => "3",
-      "traefik.http.middlewares.#{service}.retry.initialinterval" => "500ms"
+  def env_args
+    self.class.argumentize "-e", config.env if config.env.present?
   end
 
   def ssh_options
@@ -60,6 +86,7 @@ class Mrsk::Configuration
     ENV["RAILS_MASTER_KEY"] || File.read(Rails.root.join("config/master.key"))
   end
 
+
   private
     attr_accessor :config
 
@@ -73,7 +100,9 @@ class Mrsk::Configuration
       end      
     end
 
-    def parameterize(param, hash)
-      hash.flat_map { |k, v| [ param, "#{k}=#{v}" ] }
+    def role_names
+      config.servers.is_a?(Array) ? [ "web" ] : config.servers.keys.sort
     end
 end
+
+require "mrsk/configuration/role"

lib/mrsk/configuration/role.rb

@@ -0,0 +1,63 @@
+class Mrsk::Configuration::Role
+  delegate :argumentize, to: Mrsk::Configuration
+
+  attr_accessor :name
+
+  def initialize(name, config:)
+   @name, @config = name.inquiry, config
+  end
+
+  def hosts
+    @hosts ||= extract_hosts_from_config
+  end
+
+  def label_args
+    argumentize "--label", labels
+  end
+
+  def cmd
+    specializations["cmd"]
+  end
+
+  private
+    attr_accessor :config
+
+    def extract_hosts_from_config
+      if config.servers.is_a?(Array)
+        config.servers
+      else
+        servers = config.servers[name]
+        servers.is_a?(Array) ? servers : servers["hosts"]
+      end
+    end
+
+    def labels
+      if name.web?
+        default_labels.merge(traefik_labels) 
+      else
+        default_labels
+      end
+    end
+
+    def default_labels
+      { "service" => config.service, "role" => name }
+    end
+
+    def traefik_labels
+      {
+        "traefik.http.routers.#{config.service}.rule" => "'PathPrefix(`/`)'",
+        "traefik.http.services.#{config.service}.loadbalancer.healthcheck.path" => "/up",
+        "traefik.http.services.#{config.service}.loadbalancer.healthcheck.interval" => "1s",
+        "traefik.http.middlewares.#{config.service}.retry.attempts" => "3",
+        "traefik.http.middlewares.#{config.service}.retry.initialinterval" => "500ms"
+      }
+    end
+
+    def specializations
+      if config.servers.is_a?(Array) || config.servers[name].is_a?(Array)
+        { }
+      else
+        config.servers[name].without("hosts")
+      end
+    end
+end

lib/tasks/mrsk/app.rake

@@ -19,15 +19,17 @@ namespace :mrsk do
 
     desc "Run app on servers (or start them if they've already been run)"
     task :run do
-      on(MRSK_CONFIG.hosts) do |host|
-        begin
-          execute *app.run
-        rescue SSHKit::Command::Failed => e
-          if e.message =~ /already in use/
-            puts "Container with same version already deployed on #{host}, starting that instead"
-            execute *app.start, host: host
-          else
-            raise
+      MRSK_CONFIG.roles.each do |role|
+        on(MRSK_CONFIG.role(role).hosts) do |host|
+          begin
+            execute *app.run(role: role)
+          rescue SSHKit::Command::Failed => e
+            if e.message =~ /already in use/
+              puts "Container with same version already deployed on #{host}, starting that instead"
+              execute *app.start, host: host
+            else
+              raise
+            end
           end
         end
       end
@@ -64,13 +66,13 @@ namespace :mrsk do
 
       desc "Execute a custom task on the first defined server"
       task :once do
-        on(MRSK_CONFIG.hosts.first) { |host| puts capture(*app.exec(ENV["CMD"])) }
+        on(MRSK_CONFIG.primary_host) { |host| puts capture(*app.exec(ENV["CMD"])) }
       end
 
       namespace :once do
         desc "Execute Rails command on the first defined server, like CMD='runner \"puts %(Hello World)\""
         task :rails do
-          on(MRSK_CONFIG.hosts.first) { puts capture(*app.exec("bin/rails", ENV["CMD"])) }
+          on(MRSK_CONFIG.primary_host) { puts capture(*app.exec("bin/rails", ENV["CMD"])) }
         end
       end
     end

lib/tasks/mrsk/registry.rake

@@ -6,7 +6,7 @@ namespace :mrsk do
   namespace :registry do
     desc "Login to the registry locally and remotely"
     task :login do
-      run_locally             { execute *registry.login }
+      run_locally           { execute *registry.login }
       on(MRSK_CONFIG.hosts) { execute *registry.login }
     end