Create orchestrator for system dependencies

Author: Taucher2003

.gitlab-ci.yml

@@ -130,16 +130,12 @@ boot:docker:
     DOCKER_TLS_CERTDIR: /certs
     DOCKER_HOST: tcp://docker:2376
   script:
-    - docker compose -f docker-compose.dev.yml up -d
+    - docker network create sagittarius_default
     - >
       docker run
       --name sagittarius
       --network sagittarius_default
       --network-alias sagittarius
-      -e SAGITTARIUS_DATABASE_HOST=postgresql
-      -e SAGITTARIUS_DATABASE_PORT=5432
-      -e SAGITTARIUS_REDIS_HOST=redis
-      -e SAGITTARIUS_REDIS_PORT=6379
       -e RAILS_ENV=production
       ghcr.io/code0-tech/sagittarius/ci-builds:${CI_COMMIT_SHA} &
     - >

.rubocop.yml

@@ -17,6 +17,10 @@ Lint/AmbiguousBlockAssociation:
 Metrics/AbcSize:
   Enabled: false
 
+Metrics/BlockLength:
+  Exclude:
+    - lib/tasks/**/*
+
 Metrics/MethodLength:
   Enabled: false
 

Gemfile

@@ -74,3 +74,5 @@ gem 'sidekiq', '~> 7.1'
 gem 'lograge', '~> 0.14.0'
 
 gem 'declarative_policy', '~> 1.1'
+
+gem 'docker-api', '~> 2.2'

Gemfile.lock

@@ -102,9 +102,13 @@ GEM
     declarative_policy (1.1.0)
     diff-lcs (1.5.1)
     docile (1.4.0)
+    docker-api (2.2.0)
+      excon (>= 0.47.0)
+      multi_json
     drb (2.2.1)
     erubi (1.12.0)
     escape_utils (1.3.0)
+    excon (0.110.0)
     extended-markdown-filter (0.7.0)
       html-pipeline (~> 2.9)
     factory_bot (6.4.5)
@@ -153,6 +157,7 @@ GEM
     mini_mime (1.1.5)
     minitest (5.22.3)
     msgpack (1.7.2)
+    multi_json (1.15.0)
     mutex_m (0.2.0)
     net-imap (0.4.10)
       date
@@ -336,6 +341,7 @@ DEPENDENCIES
   database_cleaner-active_record (~> 2.1)
   debug
   declarative_policy (~> 1.1)
+  docker-api (~> 2.2)
   factory_bot_rails (~> 6.2)
   graphql (~> 2.1)
   graphql-docs (~> 4.0)

bin/docker-entrypoint

@@ -1,7 +1,16 @@
 #!/bin/bash -e
 
-# If running the rails server then create or migrate existing database
 if [ "${1}" == "./bin/rails" ] && [ "${2}" == "server" ]; then
+  # orchestrate dependencies
+  bundle exec rake orchestrator:start[postgresql] \
+   orchestrator:start[redis] \
+   orchestrator:await_healthy[postgresql] \
+   orchestrator:await_healthy[redis]
+
+  # create connection environment variables
+  eval $(bundle exec orchestrator:create_connection_environment[postgresql,redis])
+
+  # prepare database
   bundle exec rake db:prepare
   FILTER=01_application_settings bundle exec rake db:seed_fu
 fi

lib/sagittarius/orchestrator/container.rb

@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+module Sagittarius
+  module Orchestrator
+    class Container
+      attr_accessor :internal_container
+
+      def image
+        raise NotImplementedError
+      end
+
+      def name
+        raise NotImplementedError
+      end
+
+      def cmd
+        nil
+      end
+
+      def environment_variables
+        []
+      end
+
+      def volumes
+        []
+      end
+
+      def ports
+        nil
+      end
+
+      def healthy?
+        return false if internal_container.nil?
+
+        internal_container.refresh!
+        internal_container.info['State']['Status'] == 'running'
+      end
+
+      def self.[](container)
+        Containers.const_get(container.capitalize).new
+      end
+    end
+  end
+end

lib/sagittarius/orchestrator/containers/postgresql.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+module Sagittarius
+  module Orchestrator
+    module Containers
+      class Postgresql < Container
+        def image
+          'postgres:16.1'
+        end
+
+        def name
+          'postgresql'
+        end
+
+        def environment_variables
+          config = ActiveRecord::Base.connection_db_config.configuration_hash
+
+          %W[
+            POSTGRES_USER=#{config[:username]}
+            POSTGRES_PASSWORD=#{config[:password]}
+            POSTGRES_DB=#{config[:database]}
+          ]
+        end
+
+        def volumes
+          {
+            data: '/var/lib/postgresql/data/',
+          }
+        end
+
+        def ports
+          {
+            '5432/tcp' => [{ 'HostIp' => '127.0.0.1', 'HostPort' => '5433' }],
+          }
+        end
+
+        def healthy?
+          # exec returns [[stdout], [], exit_code]
+          super && internal_container.exec(%w[pg_isready]).last.zero?
+        end
+
+        def orchestrator_connection_details
+          return {} unless healthy?
+
+          {
+            SAGITTARIUS_DATABASE_HOST: internal_container.info['Name'].delete_prefix('/'),
+            SAGITTARIUS_DATABASE_PORT: 5432,
+          }
+        end
+      end
+    end
+  end
+end

lib/sagittarius/orchestrator/containers/redis.rb

@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+module Sagittarius
+  module Orchestrator
+    module Containers
+      class Redis < Container
+        def image
+          'redis:7.2.3-alpine'
+        end
+
+        def name
+          'redis'
+        end
+
+        def cmd
+          %w[redis-server --save 1 1 --loglevel warning]
+        end
+
+        def volumes
+          {
+            data: '/data',
+          }
+        end
+
+        def ports
+          {
+            '6379/tcp' => [{ 'HostIp' => '127.0.0.1', 'HostPort' => '6380' }],
+          }
+        end
+
+        def orchestrator_connection_details
+          return {} unless healthy?
+
+          {
+            SAGITTARIUS_REDIS_HOST: internal_container.info['Name'].delete_prefix('/'),
+            SAGITTARIUS_REDIS_PORT: 6379,
+          }
+        end
+      end
+    end
+  end
+end

lib/sagittarius/orchestrator/operator.rb

@@ -0,0 +1,96 @@
+# frozen_string_literal: true
+
+module Sagittarius
+  module Orchestrator
+    class Operator
+      ORCHESTRATOR_LABEL_PREFIX = 'tech.code0.sagittarius.orchestrator'
+      VOLUME_NAME_LABEL = "#{ORCHESTRATOR_LABEL_PREFIX}.volume.name".freeze
+      VOLUME_CONTAINER_LABEL = "#{ORCHESTRATOR_LABEL_PREFIX}.volume.container".freeze
+
+      class << self
+        def ensure_self_connected!
+          ensure_network!
+
+          self_container_id = State.self_container_id
+          return if self_container_id.nil?
+
+          network.connect(State.self_container_id)
+        end
+
+        def ensure_container_up!(container)
+          ensure_network!
+          create_container!(container) if State[container.name].internal_container.nil?
+
+          container.internal_container.refresh!
+
+          unless container.internal_container.info['NetworkSettings']['Networks'].key?(network.info['Name'])
+            network.connect(container.internal_container.id)
+          end
+          container.internal_container.start
+        end
+
+        def ensure_container_down!(container)
+          destroy_container!(container) unless State[container.name].internal_container.nil?
+        end
+
+        private
+
+        def ensure_network!
+          return unless network.nil?
+
+          Docker::Network.create(
+            unique_name('code0'),
+            'Labels' => { ORCHESTRATOR_LABEL_PREFIX => 'network' }
+          )
+        end
+
+        def network
+          Docker::Network.all(filters: JSON.dump({ 'label' => ["#{ORCHESTRATOR_LABEL_PREFIX}=network"] })).first
+        end
+
+        def ensure_volumes!(container)
+          container.volumes.each_key do |name|
+            next if State.volumes[container.name]&.key?(name.to_s)
+
+            Docker::Volume.create(
+              unique_name("#{container.name}_#{name}"),
+              'Labels' => { VOLUME_NAME_LABEL => name, VOLUME_CONTAINER_LABEL => container.name }
+            )
+          end
+
+          State.build_volumes!
+        end
+
+        def create_container!(container)
+          ensure_volumes!(container)
+          volumes = container.volumes.map do |name, path|
+            "#{State.volumes[container.name][name.to_s].info['Name']}:#{path}"
+          end
+
+          Docker::Image.create('fromImage' => container.image)
+          container.internal_container = Docker::Container.create(
+            'name' => unique_name(container.name),
+            'Image' => container.image,
+            'Labels' => { ORCHESTRATOR_LABEL_PREFIX => container.name },
+            'Cmd' => container.cmd,
+            'Env' => container.environment_variables,
+            'HostConfig' => {
+              'Binds' => volumes,
+              'PortBindings' => container.ports,
+            }
+          )
+        end
+
+        def destroy_container!(container)
+          container.internal_container.stop
+          container.internal_container.delete
+          container.internal_container = nil
+        end
+
+        def unique_name(component)
+          "#{component}_#{SecureRandom.hex}"
+        end
+      end
+    end
+  end
+end

lib/sagittarius/orchestrator/state.rb

@@ -0,0 +1,63 @@
+# frozen_string_literal: true
+
+module Sagittarius
+  module Orchestrator
+    class State
+      class << self
+        attr_accessor :containers, :volumes
+
+        def build!
+          build_containers!
+          build_volumes!
+        end
+
+        def build_containers!
+          docker_containers = Docker::Container.all(
+            all: true,
+            filters: JSON.dump({ 'label' => [Operator::ORCHESTRATOR_LABEL_PREFIX] })
+          ).to_h do |c|
+            label = c.info['Labels'][Operator::ORCHESTRATOR_LABEL_PREFIX]
+            next [nil, nil] if label.nil?
+
+            [label, c]
+          end
+
+          @containers = Container.descendants.to_h do |clazz|
+            container = clazz.new
+            container.internal_container = docker_containers[container.name]
+            [container.name, container]
+          end
+        end
+
+        def build_volumes!
+          @volumes = Docker::Volume.all(
+            filters: JSON.dump({ 'label' => [Operator::VOLUME_NAME_LABEL] })
+          ).each_with_object({}) do |v, obj|
+            name_label = v.info.dig('Labels', Operator::VOLUME_NAME_LABEL)
+            container_label = v.info.dig('Labels', Operator::VOLUME_CONTAINER_LABEL)
+            next if name_label.nil? || container_label.nil?
+
+            obj[container_label] ||= {}
+            obj[container_label][name_label] = v
+          end
+        end
+
+        def [](container_name)
+          @containers[container_name]
+        end
+
+        def self_container_id
+          container_id_from_cgroup
+        end
+
+        private
+
+        def container_id_from_cgroup
+          File.readlines('/proc/self/cgroup').find { |line| line.include?('docker') }&.split('/')&.last&.chomp
+        rescue Errno::ENOENT
+          nil
+        end
+      end
+    end
+  end
+end