Configurable Number of Lines in Healthcheck Log Output

lib/kamal/commands/healthcheck.rb

@@ -26,7 +26,7 @@ def container_health_log
   end
 
   def logs
-    pipe container_id, xargs(docker(:logs, "--tail", 50, "2>&1"))
+    pipe container_id, xargs(docker(:logs, "--tail", log_lines, "2>&1"))
   end
 
   def stop
@@ -57,4 +57,8 @@ def health_url
     def exposed_port
       config.healthcheck["exposed_port"]
     end
+
+    def log_lines
+      config.healthcheck["log_lines"]
+    end
 end

lib/kamal/configuration.rb

@@ -149,7 +149,7 @@ def sshkit
 
 
   def healthcheck
-    { "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999, "cord" => "/tmp/kamal-cord" }.merge(raw_config.healthcheck || {})
+    { "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999, "cord" => "/tmp/kamal-cord", "log_lines" => 50 }.merge(raw_config.healthcheck || {})
   end
 
   def readiness_delay

test/commands/healthcheck_test.rb

@@ -92,6 +92,13 @@ class CommandsHealthcheckTest < ActiveSupport::TestCase
       new_command.logs.join(" ")
   end
 
+  test "logs with custom lines number" do
+    @config[:healthcheck] = { "log_lines" => 150 }
+    assert_equal \
+      "docker container ls --all --filter name=^healthcheck-app-123$ --quiet | xargs docker logs --tail 150 2>&1",
+      new_command.logs.join(" ")
+  end
+
   test "logs with destination" do
     @destination = "staging"
 

test/configuration_test.rb

@@ -224,7 +224,7 @@ class ConfigurationTest < ActiveSupport::TestCase
         :volume_args=>["--volume", "/local/path:/container/path"],
         :builder=>{},
         :logging=>["--log-opt", "max-size=\"10m\""],
-        :healthcheck=>{ "path"=>"/up", "port"=>3000, "max_attempts" => 7, "exposed_port" => 3999, "cord" => "/tmp/kamal-cord" }}
+        :healthcheck=>{ "path"=>"/up", "port"=>3000, "max_attempts" => 7, "exposed_port" => 3999, "cord" => "/tmp/kamal-cord", "log_lines" => 50 }}
 
     assert_equal expected_config, @config.to_h
   end

test/integration/main_test.rb

@@ -54,7 +54,7 @@ class MainTest < IntegrationTest
     assert_equal({ user: "root", auth_methods: [ "publickey" ], keepalive: true, keepalive_interval: 30, log_level: :fatal }, config[:ssh_options])
     assert_equal({ "multiarch" => false, "args" => { "COMMIT_SHA" => version } }, config[:builder])
     assert_equal [ "--log-opt", "max-size=\"10m\"" ], config[:logging]
-    assert_equal({ "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999, "cord"=>"/tmp/kamal-cord", "cmd"=>"wget -qO- http://localhost > /dev/null || exit 1" }, config[:healthcheck])
+    assert_equal({ "path" => "/up", "port" => 3000, "max_attempts" => 7, "exposed_port" => 3999, "cord"=>"/tmp/kamal-cord", "log_lines" => 50, "cmd"=>"wget -qO- http://localhost > /dev/null || exit 1" }, config[:healthcheck])
   end
 
   private