Add container name env var for containers

Because the container name is generated it isn't possible to
determine this inside the container.

This adds the MRSK_CONTAINER_NAME env var when running the
container so it can be read by the service running inside the
container.

README.md

@@ -222,6 +222,12 @@ volumes:
   - "/local/path:/container/path"
 ```
 
+### MRSK env variables
+
+The following env variables are set when your container runs:
+
+`MRSK_CONTAINER_NAME` : this contains the current container name and version
+
 ### Using different roles for servers
 
 If your application uses separate hosts for running jobs or other roles beyond the default web running, you can specify these hosts in a dedicated role with a new entrypoint command like so:

lib/mrsk/commands/app.rb

@@ -7,6 +7,7 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
       "--restart unless-stopped",
       "--log-opt", "max-size=#{MAX_LOG_SIZE}",
       "--name", service_with_version_and_destination,
+      "-e", "MRSK_CONTAINER_NAME=\"#{service_with_version_and_destination}\"",
       *role.env_args,
       *config.volume_args,
       *role.label_args,

lib/mrsk/commands/healthcheck.rb

@@ -9,6 +9,7 @@ class Mrsk::Commands::Healthcheck < Mrsk::Commands::Base
       "--name", container_name_with_version,
       "--publish", "#{EXPOSED_PORT}:#{config.healthcheck["port"]}",
       "--label", "service=#{container_name}",
+      "-e", "MRSK_CONTAINER_NAME=\"#{container_name}\"",
       *web.env_args,
       *config.volume_args,
       config.absolute_image,

test/commands/app_test.rb

@@ -14,7 +14,7 @@ class CommandsAppTest < ActiveSupport::TestCase
 
   test "run" do
     assert_equal \
-      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -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=\"5\" --label traefik.http.middlewares.app.retry.initialinterval=\"500ms\" dhh/app:999",
+      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -e MRSK_CONTAINER_NAME=\"app-999\" -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=\"5\" --label traefik.http.middlewares.app.retry.initialinterval=\"500ms\" dhh/app:999",
       @app.run.join(" ")
   end
 
@@ -22,7 +22,7 @@ class CommandsAppTest < ActiveSupport::TestCase
     @config[:volumes] = ["/local/path:/container/path" ]
 
     assert_equal \
-      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -e RAILS_MASTER_KEY=\"456\" --volume /local/path:/container/path --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=\"5\" --label traefik.http.middlewares.app.retry.initialinterval=\"500ms\" dhh/app:999",
+      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -e MRSK_CONTAINER_NAME=\"app-999\" -e RAILS_MASTER_KEY=\"456\" --volume /local/path:/container/path --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=\"5\" --label traefik.http.middlewares.app.retry.initialinterval=\"500ms\" dhh/app:999",
       @app.run.join(" ")
   end
 
@@ -30,7 +30,7 @@ class CommandsAppTest < ActiveSupport::TestCase
     @config[:healthcheck] = { "path" => "/healthz" }
 
     assert_equal \
-      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -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=\"/healthz\" --label traefik.http.services.app.loadbalancer.healthcheck.interval=\"1s\" --label traefik.http.middlewares.app.retry.attempts=\"5\" --label traefik.http.middlewares.app.retry.initialinterval=\"500ms\" dhh/app:999",
+      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -e MRSK_CONTAINER_NAME=\"app-999\" -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=\"/healthz\" --label traefik.http.services.app.loadbalancer.healthcheck.interval=\"1s\" --label traefik.http.middlewares.app.retry.attempts=\"5\" --label traefik.http.middlewares.app.retry.initialinterval=\"500ms\" dhh/app:999",
       @app.run.join(" ")
   end
 
@@ -39,7 +39,7 @@ class CommandsAppTest < ActiveSupport::TestCase
     @app = Mrsk::Commands::App.new Mrsk::Configuration.new(@config).tap { |c| c.version = "999" }
 
     assert_equal \
-      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -e RAILS_MASTER_KEY=\"456\" --label service=\"app\" --label role=\"jobs\" --mount \"somewhere\" --cap-add dhh/app:999 bin/jobs",
+      "docker run --detach --restart unless-stopped --log-opt max-size=10m --name app-999 -e MRSK_CONTAINER_NAME=\"app-999\" -e RAILS_MASTER_KEY=\"456\" --label service=\"app\" --label role=\"jobs\" --mount \"somewhere\" --cap-add dhh/app:999 bin/jobs",
       @app.run(role: :jobs).join(" ")
   end
 

test/commands/healthcheck_test.rb

@@ -10,7 +10,7 @@ class CommandsHealthcheckTest < ActiveSupport::TestCase
 
   test "run" do
     assert_equal \
-      "docker run --detach --name healthcheck-app-123 --publish 3999:3000 --label service=healthcheck-app dhh/app:123",
+      "docker run --detach --name healthcheck-app-123 --publish 3999:3000 --label service=healthcheck-app -e MRSK_CONTAINER_NAME=\"healthcheck-app\" dhh/app:123",
       new_command.run.join(" ")
   end
 
@@ -18,7 +18,7 @@ class CommandsHealthcheckTest < ActiveSupport::TestCase
     @config[:healthcheck] = { "port" => 3001 }
 
     assert_equal \
-      "docker run --detach --name healthcheck-app-123 --publish 3999:3001 --label service=healthcheck-app dhh/app:123",
+      "docker run --detach --name healthcheck-app-123 --publish 3999:3001 --label service=healthcheck-app -e MRSK_CONTAINER_NAME=\"healthcheck-app\" dhh/app:123",
       new_command.run.join(" ")
   end
 
@@ -26,7 +26,7 @@ class CommandsHealthcheckTest < ActiveSupport::TestCase
     @destination = "staging"
 
     assert_equal \
-      "docker run --detach --name healthcheck-app-staging-123 --publish 3999:3000 --label service=healthcheck-app-staging dhh/app:123",
+      "docker run --detach --name healthcheck-app-staging-123 --publish 3999:3000 --label service=healthcheck-app-staging -e MRSK_CONTAINER_NAME=\"healthcheck-app-staging\" dhh/app:123",
       new_command.run.join(" ")
   end