Configurable Number of Lines in Healthcheck Log Output

lib/kamal/commands/healthcheck.rb

@@ -27,7 +27,7 @@ def container_health_log
   end
 
   def logs
-    pipe container_id, xargs(docker(:logs, "--tail", 50, "2>&1"))
+    pipe container_id, xargs(docker(:logs, "--tail", lines, "2>&1"))
   end
 
   def stop
@@ -54,4 +54,8 @@ def container_id
     def health_url
       "http://localhost:#{EXPOSED_PORT}#{config.healthcheck["path"]}"
     end
+
+    def lines
+      config.healthcheck["lines"]
+    end
 end

lib/kamal/configuration.rb

@@ -145,7 +145,7 @@ def sshkit
 
 
   def healthcheck
-    { "path" => "/up", "port" => 3000, "max_attempts" => 7 }.merge(raw_config.healthcheck || {})
+    { "path" => "/up", "port" => 3000, "max_attempts" => 7, "lines" => 50 }.merge(raw_config.healthcheck || {})
   end
 
   def readiness_delay

test/commands/healthcheck_test.rb

@@ -91,6 +91,13 @@ class CommandsHealthcheckTest < ActiveSupport::TestCase
       new_command.logs.join(" ")
   end
 
+  test "logs with custom lines number" do
+    @config[:healthcheck] = { "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"