Add healthcheck before deploy

lib/mrsk/cli/healthcheck.rb

@@ -0,0 +1,29 @@
+class Mrsk::Cli::Healthcheck < Mrsk::Cli::Base
+  desc "perform", "Health check the current version of the app"
+  def perform
+    on(MRSK.primary_host) do
+      begin
+        execute *MRSK.healthcheck.run
+
+        target = "Health check against #{MRSK.config.healthcheck["path"]}"
+
+        if capture_with_info(*MRSK.healthcheck.curl) == "200"
+          info "#{target} succeeded with 200 OK!"
+        else
+          # Catches 1xx, 2xx, 3xx
+          raise SSHKit::Command::Failed, "#{target} failed to return 200 OK!"
+        end
+      rescue SSHKit::Command::Failed => e
+        if e.message =~ /curl/
+          # Catches 4xx, 5xx
+          raise SSHKit::Command::Failed, "#{target} failed to return 200 OK!"
+        else
+          raise
+        end
+      ensure
+        execute *MRSK.healthcheck.stop, raise_on_non_zero_exit: false
+        execute *MRSK.healthcheck.remove, raise_on_non_zero_exit: false
+      end
+    end
+  end
+end

lib/mrsk/cli/main.rb

@@ -23,6 +23,9 @@ class Mrsk::Cli::Main < Mrsk::Cli::Base
       say "Ensure Traefik is running...", :magenta
       invoke "mrsk:cli:traefik:boot"
 
+      say "Ensure app can pass healthcheck...", :magenta
+      invoke "mrsk:cli:healthcheck:perform"
+
       invoke "mrsk:cli:app:boot"
 
       say "Prune old containers and images...", :magenta
@@ -38,6 +41,9 @@ class Mrsk::Cli::Main < Mrsk::Cli::Base
       say "Build and push app image...", :magenta
       invoke "mrsk:cli:build:deliver"
 
+      say "Ensure app can pass healthcheck...", :magenta
+      invoke "mrsk:cli:healthcheck:perform"
+
       invoke "mrsk:cli:app:boot"
     end
 
@@ -147,6 +153,9 @@ class Mrsk::Cli::Main < Mrsk::Cli::Base
   desc "build", "Build the application image"
   subcommand "build", Mrsk::Cli::Build
 
+  desc "healthcheck", "Healthcheck the application"
+  subcommand "healthcheck", Mrsk::Cli::Healthcheck
+
   desc "prune", "Prune old application images and containers"
   subcommand "prune", Mrsk::Cli::Prune
 

lib/mrsk/commander.rb

@@ -73,6 +73,10 @@ class Mrsk::Commander
     @auditor ||= Mrsk::Commands::Auditor.new(config)
   end
 
+  def healthcheck
+    @healthcheck ||= Mrsk::Commands::Healthcheck.new(config)
+  end
+
 
   def with_verbosity(level)
     old_level = self.verbosity

lib/mrsk/commands/app.rb

@@ -75,10 +75,6 @@ class Mrsk::Commands::App < Mrsk::Commands::Base
     docker :ps, "-q", *service_filter
   end
 
-  def container_id_for(container_name:)
-    docker :container, :ls, "-a", "-f", "name=#{container_name}", "-q"
-  end
-
   def current_running_version
     # FIXME: Find more graceful way to extract the version from "app-version" than using sed and tail!
     pipe \

lib/mrsk/commands/base.rb

@@ -17,6 +17,10 @@ module Mrsk::Commands
       end
     end
 
+    def container_id_for(container_name:)
+      docker :container, :ls, "-a", "-f", "name=#{container_name}", "-q"
+    end
+
     private
       def combine(*commands, by: "&&")
         commands

lib/mrsk/commands/healthcheck.rb

@@ -0,0 +1,46 @@
+class Mrsk::Commands::Healthcheck < Mrsk::Commands::Base
+  EXPOSED_PORT = 3999
+
+  def run
+    web = config.role(:web)
+
+    docker :run,
+      "-d",
+      "--name", container_name_with_version,
+      "-p", "#{EXPOSED_PORT}:#{config.healthcheck["port"]}",
+      "--label", "service=#{container_name}",
+      *web.env_args,
+      *config.volume_args,
+      config.absolute_image,
+      web.cmd
+  end
+
+  def curl
+    [ :curl, "--silent", "--output", "/dev/null", "--write-out", "'%{http_code}'", health_url ]
+  end
+
+  def stop
+    pipe \
+      container_id_for(container_name: container_name),
+      xargs(docker(:stop))
+  end
+
+  def remove
+    pipe \
+      container_id_for(container_name: container_name),
+      xargs(docker(:container, :rm))
+  end
+
+  private
+    def container_name
+      "healthcheck-#{config.service}"
+    end
+
+    def container_name_with_version
+      "healthcheck-#{config.service_with_version}"
+    end
+
+    def health_url
+      "http://localhost:#{EXPOSED_PORT}#{config.healthcheck["path"]}"
+    end
+end

lib/mrsk/configuration.rb

@@ -107,6 +107,7 @@ class Mrsk::Configuration
     end
   end
 
+
   def ssh_user
     if raw_config.ssh.present?
       raw_config.ssh["user"] || "root"
@@ -126,10 +127,15 @@ class Mrsk::Configuration
     { user: ssh_user, proxy: ssh_proxy, auth_methods: [ "publickey" ] }.compact
   end
 
+
   def audit_broadcast_cmd
     raw_config.audit_broadcast_cmd
   end
 
+  def healthcheck
+    { "path" => "/up", "port" => "3000" }.merge(raw_config.healthcheck || {})
+  end
+
 
   def valid?
     ensure_required_keys_present && ensure_env_available

lib/mrsk/configuration/role.rb

@@ -59,7 +59,7 @@ class Mrsk::Configuration::Role
       if running_traefik?
         {
           "traefik.http.routers.#{config.service}.rule" => "'PathPrefix(`/`)'",
-          "traefik.http.services.#{config.service}.loadbalancer.healthcheck.path" => "/up",
+          "traefik.http.services.#{config.service}.loadbalancer.healthcheck.path" => config.healthcheck["path"],
           "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"