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