Bump version for 0.0.2

Servers concept will encompass custom cmd and labels. Host is just the IP address.

Gemfile

@@ -1,9 +1,6 @@
 source 'https://rubygems.org'
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
-# Specify your gem's dependencies in importmap-rails.gemspec.
 gemspec
 
-group :test do
-  gem "byebug"
-end
+gem "debug"

Gemfile.lock

@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    mrsk (0.0.1)
+    mrsk (0.0.2)
       railties (>= 7.0.0)
       sshkit (~> 1.21)
 
@@ -27,12 +27,17 @@ GEM
       minitest (>= 5.1)
       tzinfo (~> 2.0)
     builder (3.2.4)
-    byebug (11.1.3)
     concurrent-ruby (1.1.10)
     crass (1.0.6)
+    debug (1.7.1)
+      irb (>= 1.5.0)
+      reline (>= 0.3.1)
     erubi (1.12.0)
     i18n (1.12.0)
       concurrent-ruby (~> 1.0)
+    io-console (0.6.0)
+    irb (1.6.2)
+      reline (>= 0.3.0)
     loofah (2.19.1)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
@@ -41,7 +46,11 @@ GEM
     net-scp (4.0.0)
       net-ssh (>= 2.6.5, < 8.0.0)
     net-ssh (7.0.1)
-    nokogiri (1.13.10-arm64-darwin)
+    nokogiri (1.14.0.rc1-arm64-darwin)
+      racc (~> 1.4)
+    nokogiri (1.14.0.rc1-x86_64-darwin)
+      racc (~> 1.4)
+    nokogiri (1.14.0.rc1-x86_64-linux)
       racc (~> 1.4)
     racc (1.6.2)
     rack (2.2.5)
@@ -60,6 +69,8 @@ GEM
       thor (~> 1.0)
       zeitwerk (~> 2.5)
     rake (13.0.6)
+    reline (0.3.2)
+      io-console (~> 0.5)
     sshkit (1.21.3)
       net-scp (>= 1.1.2)
       net-ssh (>= 2.8.0)
@@ -77,8 +88,8 @@ PLATFORMS
   x86_64-linux
 
 DEPENDENCIES
-  byebug
+  debug
   mrsk!
 
 BUNDLED WITH
-   2.2.33
+   2.4.3

README.md

@@ -1,26 +1,32 @@
 # MRSK
 
-MRSK lets you do zero-downtime deploys of Rails apps packed as containers to any host running Docker. It uses the dynamic reverse-proxy Traefik to hold requests while the new application container is started and the old one is wound down. It works across multiple hosts at the same time, using SSHKit to execute commands.
+MRSK ships zero-downtime deploys of Rails apps packed as containers to any host. It uses the dynamic reverse-proxy Traefik to hold requests while the new application container is started and the old one is wound down. It works across multiple hosts at the same time, using SSHKit to execute commands.
 
 ## Installation
 
-Create a configuration file for MRSK in `config/deploy.yml` that looks like this:
+Add the gem with `bundle add mrsk`, then run `rake mrsk:init`, and then edit the new file in `config/deploy.yml` to use the proper service name, image reference, servers to deploy on, and so on. It could look something like this:
 
 ```yaml
-service: my-app
-image: name/my-app
+service: hey
+image: 37s/hey
 servers:
   - xxx.xxx.xxx.xxx
   - xxx.xxx.xxx.xxx
 env:
-  DATABASE_URL: mysql2://username@localhost/database_name/
-  REDIS_URL: redis://host:6379/1
+  DATABASE_URL: mysql2://db1/hey_production/
+  REDIS_URL: redis://redis1:6379/1
+registry:
+  server: registry.digitalocean.com
+  username: <%= Rails.application.credentials.registry["username"] %>
+  password: <%= Rails.application.credentials.registry["password"] %>
 ```
 
-Then first login to the Docker Hub registry on the servers:
+Then ensure your encrypted credentials have the registry username + password by editing them with `rails credentials:edit`:
 
 ```
-rake mrsk:registry:login DOCKER_USER=name DOCKER_PASSWORD=pw
+registry:
+  username: real-user-name
+  password: real-password
 ```
 
 Now you're ready to deploy a multi-arch image (FIXME: currently you need to manually run `docker buildx create --use` once first):
@@ -31,25 +37,142 @@ rake mrsk:deploy
 
 This will:
 
-1. Build the image using the standard Dockerfile in the root of the application.
-2. Push the image to the registry.
-3. Pull the image on all the servers.
-4. Ensure Traefik is running and accepting traffic on port 80.
-5. Stop any containers running a previous versions of the app.
-6. Start a new container with the version of the app that matches the current git version hash.
+1. Log into the registry both locally and remotely
+2. Build the image using the standard Dockerfile in the root of the application.
+3. Push the image to the registry.
+4. Pull the image from the registry on the servers.
+5. Ensure Traefik is running and accepting traffic on port 80.
+6. Stop any containers running a previous versions of the app.
+7. Start a new container with the version of the app that matches the current git version hash.
+8. Prune unused images and stopped containers to ensure servers don't fill up.
 
-Voila! All the servers are now serving the app on port 80, and you're ready to put them behind a load balancer to serve live traffic.
+Voila! All the servers are now serving the app on port 80. If you're just running a single server, you're ready to go. If you're running multiple servers, you need to put a load balancer in front of them.
+
+## Operations
+
+### Running job hosts separately
+
+If your application uses separate job running hosts, or other roles beyond the default web running, you can specify these hosts and their custom command like so:
+
+```yaml
+servers:
+  web:
+    - xxx.xxx.xxx.xxx
+    - xxx.xxx.xxx.xxx
+  job:
+    hosts:
+      - xxx.xxx.xxx.xxx
+      - xxx.xxx.xxx.xxx
+    cmd: bin/jobs
+```
+
+The application will be deployed to all hosts, but only those in the `web` role will be labeled to run under traefik. If you want to run custom commands on all hosts in a role, you can use `rake mrsk:app:exec:rails CMD=about ROLES=job`.
+
+### Executing commands
+
+If you need to execute commands inside the Rails containers, you can use `rake mrsk:app:exec`, `rake mrsk:app:exec:once`, `rake mrsk:app:exec:rails`, and `rake mrsk:app:exec:once:rails`. Examples:
+
+```bash
+# Runs command on all servers
+rake mrsk:app:exec CMD='ruby -v'
+App Host: xxx.xxx.xxx.xxx
+ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
+
+App Host: xxx.xxx.xxx.xxx
+ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
+
+# Runs command on first server
+rake mrsk:app:exec:once CMD='cat .ruby-version'
+3.1.3
+
+# Runs Rails command on all servers
+rake mrsk:app:exec:rails CMD=about
+App Host: xxx.xxx.xxx.xxx
+About your application's environment
+Rails version             7.1.0.alpha
+Ruby version              ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
+RubyGems version          3.3.26
+Rack version              2.2.5
+Middleware                ActionDispatch::HostAuthorization, Rack::Sendfile, ActionDispatch::Static, ActionDispatch::Executor, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, ActionDispatch::RemoteIp, Rails::Rack::Logger, ActionDispatch::ShowExceptions, ActionDispatch::DebugExceptions, ActionDispatch::Callbacks, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, ActionDispatch::ContentSecurityPolicy::Middleware, ActionDispatch::PermissionsPolicy::Middleware, Rack::Head, Rack::ConditionalGet, Rack::ETag, Rack::TempfileReaper
+Application root          /rails
+Environment               production
+Database adapter          sqlite3
+Database schema version   20221231233303
+
+App Host: xxx.xxx.xxx.xxx
+About your application's environment
+Rails version             7.1.0.alpha
+Ruby version              ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
+RubyGems version          3.3.26
+Rack version              2.2.5
+Middleware                ActionDispatch::HostAuthorization, Rack::Sendfile, ActionDispatch::Static, ActionDispatch::Executor, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, ActionDispatch::RemoteIp, Rails::Rack::Logger, ActionDispatch::ShowExceptions, ActionDispatch::DebugExceptions, ActionDispatch::Callbacks, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, ActionDispatch::ContentSecurityPolicy::Middleware, ActionDispatch::PermissionsPolicy::Middleware, Rack::Head, Rack::ConditionalGet, Rack::ETag, Rack::TempfileReaper
+Application root          /rails
+Environment               production
+Database adapter          sqlite3
+Database schema version   20221231233303
+
+# Runs Rails command on first server
+rake mrsk:app:exec:once:rails CMD='db:version'
+database: storage/production.sqlite3
+Current version: 20221231233303
+```
+
+### Inspecting
+
+You can see the state of your servers by running `rake mrsk:info`. It'll show something like this:
+
+```
+Traefik Host: xxx.xxx.xxx.xxx
+CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                               NAMES
+6195b2a28c81   traefik   "/entrypoint.sh --pr…"   30 minutes ago   Up 19 minutes   0.0.0.0:80->80/tcp, :::80->80/tcp   traefik
+
+Traefik Host: 164.92.105.119
+CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                               NAMES
+de14a335d152   traefik   "/entrypoint.sh --pr…"   30 minutes ago   Up 19 minutes   0.0.0.0:80->80/tcp, :::80->80/tcp   traefik
+
+App Host: 164.90.145.60
+CONTAINER ID   IMAGE                                                                         COMMAND                  CREATED          STATUS          PORTS      NAMES
+badb1aa51db3   registry.digitalocean.com/user/app:6ef8a6a84c525b123c5245345a8483f86d05a123   "/rails/bin/docker-e…"   13 minutes ago   Up 13 minutes   3000/tcp   chat-6ef8a6a84c525b123c5245345a8483f86d05a123
+
+App Host: 164.92.105.119
+CONTAINER ID   IMAGE                                                                         COMMAND                  CREATED          STATUS          PORTS      NAMES
+1d3c91ed1f55   registry.digitalocean.com/user/app:6ef8a6a84c525b123c5245345a8483f86d05a123   "/rails/bin/docker-e…"   13 minutes ago   Up 13 minutes   3000/tcp   chat-6ef8a6a84c525b123c5245345a8483f86d05a123
+```
+
+You can also see just info for app containers with `rake mrsk:app:info` or just for Traefik with `rake mrsk:traefik:info`.
+
+### Rollback
+
+If you've discovered a bad deploy, you can quickly rollback by reactivating the old, paused container image. You can see what old containers are available for rollback by running `rake mrsk:app:containers`. It'll give you a presentation similar to `rake mrsk:app:info`, but include all the old containers as well. Showing something like this:
+
+```
+App Host: 164.92.105.119
+CONTAINER ID   IMAGE                                                                         COMMAND                  CREATED          STATUS                      PORTS      NAMES
+1d3c91ed1f51   registry.digitalocean.com/user/app:6ef8a6a84c525b123c5245345a8483f86d05a123   "/rails/bin/docker-e…"   19 minutes ago   Up 19 minutes               3000/tcp   chat-6ef8a6a84c525b123c5245345a8483f86d05a123
+539f26b28369   registry.digitalocean.com/user/app:e5d9d7c2b898289dfbc5f7f1334140d984eedae4   "/rails/bin/docker-e…"   31 minutes ago   Exited (1) 27 minutes ago              chat-e5d9d7c2b898289dfbc5f7f1334140d984eedae4
+
+App Host: 164.90.145.60
+CONTAINER ID   IMAGE                                                                         COMMAND                  CREATED          STATUS                      PORTS      NAMES
+badb1aa51db4   registry.digitalocean.com/user/app:6ef8a6a84c525b123c5245345a8483f86d05a123   "/rails/bin/docker-e…"   19 minutes ago   Up 19 minutes               3000/tcp   chat-6ef8a6a84c525b123c5245345a8483f86d05a123
+6f170d1172ae   registry.digitalocean.com/user/app:e5d9d7c2b898289dfbc5f7f1334140d984eedae4   "/rails/bin/docker-e…"   31 minutes ago   Exited (1) 27 minutes ago              chat-e5d9d7c2b898289dfbc5f7f1334140d984eedae4
+```
+
+From the example above, we can see that `e5d9d7c2b898289dfbc5f7f1334140d984eedae4` was the last version, so it's available as a rollback target. We can perform this rollback by running `rake mrsk:rollback VERSION=e5d9d7c2b898289dfbc5f7f1334140d984eedae4`. That'll stop `6ef8a6a84c525b123c5245345a8483f86d05a123` and then start `e5d9d7c2b898289dfbc5f7f1334140d984eedae4`. Because the old container is still available, this is very quick. Nothing to download from the registry.
+
+Note that by default old containers are pruned after 3 days when you run `rake mrsk:deploy`.
+
+### Removing
+
+If you wish to remove the entire application, including Traefik, containers, images, and registry session, you can run `rake mrsk:remove`. This will leave the servers clean.
 
 ## Stage of development
 
 This is alpha software. Lots of stuff is missing. Here are some of the areas we seek to improve:
 
-- Use of other registries than Docker Hub
 - Adapterize commands to work with Podman and other container runners
-- Better flow for secrets and ENV
 - Possibly switching to a bin/mrsk command rather than raw rake
-- Integrate wirmth cloud CI pipelines
+- Integrate with cloud CI pipelines
 
 ## License
 
-Mrsk is released under the [MIT License](https://opensource.org/licenses/MIT).
+MRSK is released under the [MIT License](https://opensource.org/licenses/MIT).

lib/mrsk/commands.rb

@@ -1,3 +1,5 @@
+require "sshkit"
+
 module Mrsk::Commands
   class Base
     attr_accessor :config
@@ -5,6 +7,16 @@ module Mrsk::Commands
     def initialize(config)
       @config = config
     end
+
+    private
+      def docker(*args)
+        args.compact.unshift :docker
+      end
+
+      # Copied from SSHKit::Backend::Abstract#redact to be available inside Commands classes
+      def redact(arg) # Used in execute_command to hide redact() args a user passes in
+        arg.to_s.extend(SSHKit::Redaction) # to_s due to our inability to extend Integer, etc
+      end      
   end
 end
 

lib/mrsk/commands/app.rb

@@ -1,22 +1,66 @@
 class Mrsk::Commands::App < Mrsk::Commands::Base
   def push
     # TODO: Run 'docker buildx create --use' when needed
-    "docker buildx build --push --platform=linux/amd64,linux/arm64 -t #{config.absolute_image} ."
+    # TODO: Make multiarch an option so Linux users can enjoy speedier builds
+    docker :buildx, :build, "--push", "--platform linux/amd64,linux/arm64", "-t", config.absolute_image, "."
   end
 
   def pull
-    "docker pull #{config.absolute_image}"
+    docker :pull, config.absolute_image
+  end
+
+  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.env_args,
+      *role.label_args,
+      config.absolute_image,
+      role.cmd
   end
 
   def start
-    "docker run -d --rm --name #{config.service_with_version} #{config.envs} #{config.labels} #{config.absolute_image}"
+    docker :start, config.service_with_version
   end
 
   def stop
-    "docker ps -q --filter label=service=#{config.service} | xargs docker stop"
+    [ "docker ps -q #{service_filter.join(" ")} | xargs docker stop" ]
   end
 
   def info
-    "docker ps --filter label=service=#{config.service}"
+    docker :ps, *service_filter
   end
+
+  def logs
+    [ "docker ps -q #{service_filter.join(" ")} | xargs docker logs -f" ]
+  end
+
+  def exec(*command)
+    docker :exec, 
+      "-e", redact("RAILS_MASTER_KEY=#{config.master_key}"),
+      *config.env_args,
+      config.service_with_version,
+      *command
+  end
+
+  def list_containers
+    docker :container, :ls, "-a", *service_filter
+  end
+
+  def remove_containers
+    docker :container, :prune, "-f", *service_filter
+  end
+
+  def remove_images
+    docker :image, :prune, "-a", "-f", *service_filter
+  end
+
+  private
+    def service_filter
+      [ "--filter", "label=service=#{config.service}" ]
+    end
 end

lib/mrsk/commands/registry.rb

@@ -1,5 +1,11 @@
 class Mrsk::Commands::Registry < Mrsk::Commands::Base
+  delegate :registry, to: :config
+
   def login
-    "docker login #{config.registry["server"]} -u #{config.registry["username"]} -p #{config.registry["password"]}"
+    docker :login, registry["server"], "-u", redact(registry["username"]), "-p", redact(registry["password"])
+  end
+
+  def logout
+    docker :logout, registry["server"]
   end
 end

lib/mrsk/commands/traefik.rb

@@ -1,17 +1,35 @@
 class Mrsk::Commands::Traefik < Mrsk::Commands::Base
+  def run
+    docker :run, "--name traefik",
+      "-d",
+      "--restart unless-stopped",
+      "-p 80:80",
+      "-v /var/run/docker.sock:/var/run/docker.sock",
+      "traefik",
+      "--providers.docker"
+  end
+
   def start
-    "docker run --name traefik " + 
-      "--rm -d " +
-      "-p 80:80 " +
-      "-v /var/run/docker.sock:/var/run/docker.sock " +
-      "traefik --providers.docker"
+    docker :container, :start, "traefik"
   end
 
   def stop
-    "docker container stop traefik"
+    docker :container, :stop, "traefik"
   end
 
   def info
-    "docker ps --filter name=traefik"
+    docker :ps, "--filter", "name=traefik"
+  end
+
+  def logs
+    docker :logs, "traefik"
+  end
+
+  def remove_container
+    docker :container, :prune, "-f", "--filter", "label=org.opencontainers.image.title=Traefik"
+  end
+
+  def remove_image
+    docker :image, :prune, "-a", "-f", "--filter", "label=org.opencontainers.image.title=Traefik"
   end
 end

lib/mrsk/configuration.rb

@@ -1,60 +1,92 @@
 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_file(file).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
 
-  def initialize(config)
+  def initialize(config, validate: true)
     @config = ActiveSupport::InheritableOptions.new(config)
-    ensure_required_keys_present
+    ensure_required_keys_present if validate
   end
 
-  def servers
-    ENV["SERVERS"] || config.servers
+
+  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
+    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
 
-  def absolute_image
-    [ config.registry["server"], image_with_version ].compact.join("/")
+  def repository
+    [ config.registry["server"], image ].compact.join("/")
   end
 
-  def image_with_version
-    "#{image}:#{version}"
+  def absolute_image
+    "#{repository}:#{version}"
   end
 
   def service_with_version
     "#{service}-#{version}"
   end
 
-  def envs
-    parameterize "-e", \
-      { "RAILS_MASTER_KEY" => master_key }.merge(env || {})
-  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
     { user: config.ssh_user || "root", auth_methods: [ "publickey" ] }
   end
 
+  def master_key
+    ENV["RAILS_MASTER_KEY"] || File.read(Rails.root.join("config/master.key"))
+  end
+
+
   private
     attr_accessor :config
 
@@ -68,11 +100,9 @@ class Mrsk::Configuration
       end      
     end
 
-    def parameterize(param, hash)
-      hash.collect { |k, v| "#{param} #{k}=#{v}" }.join(" ")
-    end
-
-    def master_key
-      ENV["RAILS_MASTER_KEY"] || File.read(Rails.root.join("config/master.key"))
+    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/mrsk/version.rb

@@ -1,3 +1,3 @@
 module Mrsk
-  VERSION = "0.0.1"
+  VERSION = "0.0.2"
 end

lib/tasks/mrsk/app.rake

@@ -4,28 +4,95 @@ app = Mrsk::Commands::App.new(MRSK_CONFIG)
 
 namespace :mrsk do
   namespace :app do
-    desc "Build and push app image to servers"
+    desc "Deliver a newly built app image to servers"
+    task deliver: %i[ push pull ]
+
+    desc "Build locally and push app image to registry"
     task :push do
-      run_locally             { execute app.push }
-      on(MRSK_CONFIG.servers) { execute app.pull }
+      run_locally { execute *app.push } unless ENV["VERSION"]
     end
 
-    desc "Start app on servers"
+    desc "Pull app image from the registry onto servers"
+    task :pull do
+      on(MRSK_CONFIG.hosts) { execute *app.pull }
+    end
+
+    desc "Run app on servers (or start them if they've already been run)"
+    task :run do
+      MRSK_CONFIG.roles.each do |role|
+        on(role.hosts) do |host|
+          begin
+            execute *app.run(role: role.name)
+          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
+    end
+
+    desc "Start existing app on servers"
     task :start do
-      on(MRSK_CONFIG.servers) { execute app.start }
+      on(MRSK_CONFIG.hosts) { execute *app.start, raise_on_non_zero_exit: false }
     end
 
     desc "Stop app on servers"
     task :stop do
-      on(MRSK_CONFIG.servers) { execute app.stop, raise_on_non_zero_exit: false }
+      on(MRSK_CONFIG.hosts) { execute *app.stop, raise_on_non_zero_exit: false }
     end
 
-    desc "Restart app on servers"
+    desc "Start app on servers (use VERSION=<git-hash> to designate which version)"
     task restart: %i[ stop start ]
 
     desc "Display information about app containers"
     task :info do
-      on(MRSK_CONFIG.servers) { |host| puts "Host: #{host}\n" + capture(app.info) + "\n\n" }
+      on(MRSK_CONFIG.hosts) { |host| puts "App Host: #{host}\n" + capture(*app.info) + "\n\n" }
+    end
+
+    desc "Execute a custom task on servers passed in as CMD='bin/rake some:task'"
+    task :exec do
+      on(MRSK_CONFIG.hosts) { |host| puts "App Host: #{host}\n" + capture(*app.exec(ENV["CMD"])) + "\n\n" }
+    end
+
+    namespace :exec do
+      desc "Execute Rails command on servers, like CMD='runner \"puts %(Hello World)\""
+      task :rails do
+        on(MRSK_CONFIG.hosts) { |host| puts "App Host: #{host}\n" + capture(*app.exec("bin/rails", ENV["CMD"])) + "\n\n" }
+      end
+
+      desc "Execute a custom task on the first defined server"
+      task :once do
+        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.primary_host) { puts capture(*app.exec("bin/rails", ENV["CMD"])) }
+        end
+      end
+    end
+
+    desc "List all the app containers currently on servers"
+    task :containers do
+      on(MRSK_CONFIG.hosts) { |host| puts "App Host: #{host}\n" + capture(*app.list_containers) + "\n\n" }
+    end
+
+    desc "Tail logs from app containers"
+    task :logs do
+      on(MRSK_CONFIG.hosts) { execute *app.logs }
+    end
+
+    desc "Remove app containers and images from servers"
+    task remove: %i[ stop ] do
+      on(MRSK_CONFIG.hosts) do
+        execute *app.remove_containers
+        execute *app.remove_images
+      end
     end
   end
 end

lib/tasks/mrsk/mrsk.rake

@@ -1,12 +1,26 @@
+require_relative "setup"
+
 namespace :mrsk do
+  desc "Deploy app for the first time to a fresh server"
+  task fresh: %w[ server:bootstrap registry:login app:deliver traefik:run app:stop app:run ]
+
   desc "Push the latest version of the app, ensure Traefik is running, then restart app"
-  task deploy: [ "app:push", "traefik:start", "app:restart" ]
+  task deploy: %w[ registry:login app:deliver traefik:run app:stop app:run prune ]
+
+  desc "Rollback to VERSION=x that was already run as a container on servers"
+  task rollback: %w[ app:restart ]
 
   desc "Display information about Traefik and app containers"
-  task info: [ "traefik:info", "app:info" ]
+  task info: %w[ traefik:info app:info ]
 
-  desc "Create config stub"
+  desc "Create config stub in config/deploy.yml"
   task :init do
-    Rails.root.join("config/deploy.yml")
+    require "fileutils"
+    FileUtils.cp_r \
+      Pathname.new(File.expand_path("templates/deploy.yml", __dir__)),
+      Rails.root.join("config/deploy.yml")
   end
+
+  desc "Remove Traefik, app, and registry session from servers"
+  task remove: %w[ traefik:remove app:remove registry:logout ]
 end

lib/tasks/mrsk/prune.rake

@@ -0,0 +1,18 @@
+require_relative "setup"
+
+namespace :mrsk do
+  desc "Prune unused images and stopped containers"
+  task prune: %w[ prune:containers prune:images ]
+
+  namespace :prune do
+    desc "Prune unused images older than 30 days"
+    task :images do
+      on(MRSK_CONFIG.hosts) { execute "docker image prune -f --filter 'until=720h'" }
+    end
+
+    desc "Prune stopped containers for the service older than 3 days"
+    task :containers do
+      on(MRSK_CONFIG.hosts) { execute "docker container prune -f --filter label=service=#{MRSK_CONFIG.service} --filter 'until=72h'" }
+    end
+  end
+end

lib/tasks/mrsk/registry.rake

@@ -6,8 +6,13 @@ namespace :mrsk do
   namespace :registry do
     desc "Login to the registry locally and remotely"
     task :login do
-      run_locally             { execute registry.login }
-      on(MRSK_CONFIG.servers) { execute registry.login }
+      run_locally           { execute *registry.login }
+      on(MRSK_CONFIG.hosts) { execute *registry.login }
+    end
+
+    desc "Logout of the registry remotely"
+    task :logout do
+      on(MRSK_CONFIG.hosts) { execute *registry.logout }
     end
   end
 end

lib/tasks/mrsk/server.rake

@@ -0,0 +1,11 @@
+require_relative "setup"
+
+namespace :mrsk do
+  namespace :server do
+    desc "Setup Docker on the remote servers"
+    task :bootstrap do
+      # FIXME: Detect when apt-get is not available and use the appropriate alternative
+      on(MRSK_CONFIG.hosts) { execute "apt-get install docker.io -y" }
+    end
+  end
+end

lib/tasks/mrsk/setup.rb

@@ -3,6 +3,14 @@ require "sshkit/dsl"
 
 include SSHKit::DSL
 
-MRSK_CONFIG = Mrsk::Configuration.load_file(Rails.root.join("config/deploy.yml"))
+if (config_file = Rails.root.join("config/deploy.yml")).exist?
+  MRSK_CONFIG = Mrsk::Configuration.load_file(config_file)
 
-SSHKit::Backend::Netssh.configure { |ssh| ssh.ssh_options = MRSK_CONFIG.ssh_options }
+  SSHKit::Backend::Netssh.configure { |ssh| ssh.ssh_options = MRSK_CONFIG.ssh_options }
+
+  # No need to use /usr/bin/env, just clogs up the logs
+  SSHKit.config.command_map[:docker] = "docker"
+else
+  # MRSK is missing config/deploy.yml – run 'rake mrsk:init'
+  MRSK_CONFIG = Mrsk::Configuration.new({}, validate: false)
+end

lib/tasks/mrsk/templates/deploy.yml

@@ -0,0 +1,21 @@
+# Name of your application will be used for uniquely configuring Traefik and app containers.
+# Your Dockerfile should set LABEL service=the-same-value to ensure image pruning works.
+service: my-app
+
+# Name of the container image
+image: user/chat
+
+# All the servers targeted for deploy. You can reference a single server for a command by using SERVERS=xxx.xxx.xxx.xxx
+servers:
+  - xxx.xxx.xxx.xxx
+
+# The following envs are made available to the container when started
+env:
+  # Remember never to put passwords or tokens directly into this file, use encrypted credentials
+  # REDIS_URL: redis://x/y
+
+registry:
+  # Specify the registry server, if you're not using Docker Hub
+  # server: registry.digitalocean.com / ghcr.io / ...
+  username: <%= Rails.application.credentials.registry["username"] %>
+  password: <%= Rails.application.credentials.registry["password"] %>

lib/tasks/mrsk/traefik.rake

@@ -4,22 +4,35 @@ traefik = Mrsk::Commands::Traefik.new(MRSK_CONFIG)
 
 namespace :mrsk do
   namespace :traefik do
-    desc "Start Traefik"
+    desc "Run Traefik on servers"
+    task :run do
+      on(MRSK_CONFIG.role(:web).hosts) { execute *traefik.run, raise_on_non_zero_exit: false }
+    end
+
+    desc "Start existing Traefik on servers"
     task :start do
-      on(MRSK_CONFIG.servers) { execute traefik.start, raise_on_non_zero_exit: false }
+      on(MRSK_CONFIG.role(:web).hosts) { execute *traefik.start, raise_on_non_zero_exit: false }
     end
 
-    desc "Stop Traefik"
+    desc "Stop Traefik on servers"
     task :stop do
-      on(MRSK_CONFIG.servers) { execute traefik.stop, raise_on_non_zero_exit: false }
+      on(MRSK_CONFIG.role(:web).hosts) { execute *traefik.stop, raise_on_non_zero_exit: false }
     end
 
-    desc "Restart Traefik"
+    desc "Restart Traefik on servers"
     task restart: %i[ stop start ]
 
-    desc "Display information about Traefik containers"
+    desc "Display information about Traefik containers from servers"
     task :info do
-      on(MRSK_CONFIG.servers) { |host| puts "Host: #{host}\n" + capture(traefik.info) + "\n\n" }
+      on(MRSK_CONFIG.role(:web).hosts) { |host| puts "Traefik Host: #{host}\n" + capture(*traefik.info) + "\n\n" }
+    end
+
+    desc "Remove Traefik container and image from servers"
+    task remove: %i[ stop ] do
+      on(MRSK_CONFIG.role(:web).hosts) do
+        execute *traefik.remove_container
+        execute *traefik.remove_image
+      end
     end
   end
 end

test/app_command_test.rb

@@ -0,0 +1,18 @@
+require "test_helper"
+require "mrsk/configuration"
+require "mrsk/commands"
+
+ENV["VERSION"] = "123"
+ENV["RAILS_MASTER_KEY"] = "456"
+
+class AppCommandTest < ActiveSupport::TestCase
+  setup do
+    @config = { service: "app", image: "dhh/app", registry: { "username" => "dhh", "password" => "secret" }, servers: [ "1.1.1.1" ] }
+    @app = Mrsk::Commands::App.new Mrsk::Configuration.new(@config)
+  end
+
+  test "run" do
+    assert_equal \
+      [:docker, :run, "-d", "--restart unless-stopped", "--name", "app-123", "-e", "RAILS_MASTER_KEY=456", "--label", "service=app", "--label", "role=web", "--label", "traefik.http.routers.app.rule='PathPrefix(`/`)'", "--label", "traefik.http.services.app.loadbalancer.healthcheck.path=/up", "--label", "traefik.http.services.app.loadbalancer.healthcheck.interval=1s", "--label", "traefik.http.middlewares.app.retry.attempts=3", "--label", "traefik.http.middlewares.app.retry.initialinterval=500ms", "dhh/app:123"], @app.run
+  end
+end

test/configuration_role_test.rb

@@ -0,0 +1,45 @@
+require "test_helper"
+require "mrsk/configuration"
+
+ENV["VERSION"] = "123"
+
+class ConfigurationRoleTest < ActiveSupport::TestCase
+  setup do
+    @deploy = {
+      service: "app", image: "dhh/app", registry: { "username" => "dhh", "password" => "secret" },
+      servers: [ "1.1.1.1", "1.1.1.2" ]
+    }
+
+    @config = Mrsk::Configuration.new(@deploy)
+
+    @deploy_with_roles = @deploy.dup.merge({
+      servers: {
+        "web" => [ "1.1.1.1", "1.1.1.2" ],
+        "workers" => {
+          "hosts" => [ "1.1.1.3", "1.1.1.4" ],
+          "cmd" => "bin/jobs"
+        }
+      }
+    })
+
+    @config_with_roles = Mrsk::Configuration.new(@deploy_with_roles)
+  end
+
+  test "hosts" do
+    assert_equal [ "1.1.1.1", "1.1.1.2" ], @config.role(:web).hosts
+    assert_equal [ "1.1.1.3", "1.1.1.4" ], @config_with_roles.role(:workers).hosts
+  end
+
+  test "label args" do
+    assert_equal [ "--label", "service=app", "--label", "role=workers" ], @config_with_roles.role(:workers).label_args
+  end
+
+  test "special label args for web" do
+    assert_equal [ "--label", "service=app", "--label", "role=web", "--label", "traefik.http.routers.app.rule='PathPrefix(`/`)'", "--label", "traefik.http.services.app.loadbalancer.healthcheck.path=/up", "--label", "traefik.http.services.app.loadbalancer.healthcheck.interval=1s", "--label", "traefik.http.middlewares.app.retry.attempts=3", "--label", "traefik.http.middlewares.app.retry.initialinterval=500ms"], @config.role(:web).label_args
+  end
+
+  test "cmd" do
+    assert_nil @config.role(:web).cmd
+    assert_equal "bin/jobs", @config_with_roles.role(:workers).cmd
+  end
+end

test/configuration_test.rb

@@ -2,28 +2,116 @@ require "test_helper"
 require "mrsk/configuration"
 
 ENV["VERSION"] = "123"
+ENV["RAILS_MASTER_KEY"] = "456"
 
 class ConfigurationTest < ActiveSupport::TestCase
   setup do
-    @config = { service: "app", image: "dhh/app", registry: { "username" => "dhh", "password" => "secret" } }
+    @deploy = {
+      service: "app", image: "dhh/app",
+      registry: { "username" => "dhh", "password" => "secret" },
+      env: { "REDIS_URL" => "redis://x/y" },
+      servers: [ "1.1.1.1", "1.1.1.2" ]
+    }
+
+    @config = Mrsk::Configuration.new(@deploy)
+
+    @deploy_with_roles = @deploy.dup.merge({
+      servers: { "web" => [ "1.1.1.1", "1.1.1.2" ], "workers" => { "hosts" => [ "1.1.1.3", "1.1.1.4" ] } } })
+
+    @config_with_roles = Mrsk::Configuration.new(@deploy_with_roles)
   end
 
   test "ensure valid keys" do
     assert_raise(ArgumentError) do
-      Mrsk::Configuration.new(@config.tap { _1.delete(:service) })
-      Mrsk::Configuration.new(@config.tap { _1.delete(:image) })
-      Mrsk::Configuration.new(@config.tap { _1.delete(:registry) })
+      Mrsk::Configuration.new(@deploy.tap { _1.delete(:service) })
+      Mrsk::Configuration.new(@deploy.tap { _1.delete(:image) })
+      Mrsk::Configuration.new(@deploy.tap { _1.delete(:registry) })
 
-      Mrsk::Configuration.new(@config.tap { _1[:registry].delete("username") })
-      Mrsk::Configuration.new(@config.tap { _1[:registry].delete("password") })
+      Mrsk::Configuration.new(@deploy.tap { _1[:registry].delete("username") })
+      Mrsk::Configuration.new(@deploy.tap { _1[:registry].delete("password") })
     end
   end
 
-  test "absolute image" do
-    configuration = Mrsk::Configuration.new(@config)
-    assert_equal "dhh/app:123", configuration.absolute_image
+  test "roles" do
+    assert_equal %w[ web ], @config.roles.collect(&:name)
+    assert_equal %w[ web workers ], @config_with_roles.roles.collect(&:name)
+  end
 
-    configuration = Mrsk::Configuration.new(@config.tap { |c| c[:registry].merge!({ "server" => "ghcr.io" }) })
-    assert_equal "ghcr.io/dhh/app:123", configuration.absolute_image
+  test "role" do
+    assert_equal "web", @config.role(:web).name
+    assert_equal "workers", @config_with_roles.role(:workers).name
+    assert_nil @config.role(:missing)
+  end
+
+  test "hosts" do
+    assert_equal [ "1.1.1.1", "1.1.1.2"], @config.hosts
+    assert_equal [ "1.1.1.1", "1.1.1.2", "1.1.1.3", "1.1.1.4" ], @config_with_roles.hosts
+  end
+
+  test "hosts from ENV" do
+    ENV["HOSTS"] = "1.1.1.5,1.1.1.6"
+    assert_equal [ "1.1.1.5", "1.1.1.6"], @config.hosts
+  ensure
+    ENV["HOSTS"] = nil
+  end
+
+  test "hosts from ENV roles" do
+    ENV["ROLES"] = "web,workers"
+    assert_equal [ "1.1.1.1", "1.1.1.2", "1.1.1.3", "1.1.1.4" ], @config_with_roles.hosts
+
+    ENV["ROLES"] = "workers"
+    assert_equal [ "1.1.1.3", "1.1.1.4" ], @config_with_roles.hosts
+  ensure
+    ENV["ROLES"] = nil
+  end
+
+  test "primary host" do
+    assert_equal "1.1.1.1", @config.primary_host
+    assert_equal "1.1.1.1", @config_with_roles.primary_host
+  end
+
+
+  test "version" do
+    assert_equal "123", @config.version
+  end
+
+  test "repository" do
+    assert_equal "dhh/app", @config.repository
+
+    config = Mrsk::Configuration.new(@deploy.tap { |c| c[:registry].merge!({ "server" => "ghcr.io" }) })
+    assert_equal "ghcr.io/dhh/app", config.repository
+  end
+
+  test "absolute image" do
+    assert_equal "dhh/app:123", @config.absolute_image
+
+    config = Mrsk::Configuration.new(@deploy.tap { |c| c[:registry].merge!({ "server" => "ghcr.io" }) })
+    assert_equal "ghcr.io/dhh/app:123", config.absolute_image
+  end
+
+  test "service with version" do
+    assert_equal "app-123", @config.service_with_version
+  end
+
+
+  test "env args" do
+    assert_equal [ "-e", "REDIS_URL=redis://x/y" ], @config.env_args
+  end
+
+  test "ssh options" do
+    assert_equal "root", @config.ssh_options[:user]
+
+    config = Mrsk::Configuration.new(@deploy.tap { |c| c[:ssh_user] = "app" })
+    assert_equal "app", @config.ssh_options[:user]
+  end
+
+  test "master key" do
+    assert_equal "456", @config.master_key
+  end
+
+
+  test "erb evaluation of yml config" do
+    config = Mrsk::Configuration.load_file Pathname.new(File.expand_path("fixtures/deploy.erb.yml", __dir__))
+    assert_equal "my-user", config.registry["username"]
   end
 end

test/fixtures/deploy.erb.yml

@@ -0,0 +1,11 @@
+service: app
+image: dhh/app
+servers:
+  - 1.1.1.1
+  - 1.1.1.2
+env:
+  REDIS_URL: redis://x/y
+registry:
+  server: registry.digitalocean.com
+  username: <%= "my-user" %>
+  password: <%= "my-password" %>

test/test_helper.rb

@@ -1,6 +1,7 @@
 require "bundler/setup"
 require "active_support/test_case"
 require "active_support/testing/autorun"
+require "debug"
 
 ActiveSupport::LogSubscriber.logger = ActiveSupport::Logger.new(STDOUT) if ENV["VERBOSE"]