Merge pull request #40807 from wpjunior/plugin-feedback

Improve error feedback when plugin does not implement desired interface

daemon/logger/factory.go

@@ -41,7 +41,11 @@ func ListDrivers() []string {
 }
 
 func (lf *logdriverFactory) register(name string, c Creator) error {
-	if lf.driverRegistered(name) {
+	registered, err := lf.driverRegistered(name)
+	if err != nil {
+		return err
+	}
+	if registered {
 		return fmt.Errorf("logger: log driver named '%s' is already registered", name)
 	}
 
@@ -51,18 +55,22 @@ func (lf *logdriverFactory) register(name string, c Creator) error {
 	return nil
 }
 
-func (lf *logdriverFactory) driverRegistered(name string) bool {
+func (lf *logdriverFactory) driverRegistered(name string) (bool, error) {
 	lf.m.Lock()
 	_, ok := lf.registry[name]
 	lf.m.Unlock()
 	if !ok {
 		if pluginGetter != nil { // this can be nil when the init functions are running
-			if l, _ := getPlugin(name, plugingetter.Lookup); l != nil {
-				return true
+			l, err := getPlugin(name, plugingetter.Lookup)
+			if err != nil {
+				return false, err
+			}
+			if l != nil {
+				return true, nil
 			}
 		}
 	}
-	return ok
+	return ok, nil
 }
 
 func (lf *logdriverFactory) registerLogOptValidator(name string, l LogOptValidator) error {
@@ -147,7 +155,11 @@ func ValidateLogOpts(name string, cfg map[string]string) error {
 		return err
 	}
 
-	if !factory.driverRegistered(name) {
+	registered, err := factory.driverRegistered(name)
+	if err != nil {
+		return err
+	}
+	if !registered {
 		return fmt.Errorf("logger: no log driver named '%s' is registered", name)
 	}
 

hack/make/test-docker-py

@@ -10,12 +10,13 @@ source hack/make/.integration-test-helpers
 : "${DOCKER_PY_COMMIT:=4.2.1}"
 
 # custom options to pass py.test
+# TODO remove these skip once we update to a docker-py version that has https://github.com/docker/docker-py/pull/2549: CreateContainerTest::test_invalid_log_driver_raises_exception
 #
 # This option can be used to temporarily skip flaky tests (using the `--deselect`
 # flag) until they are fixed upstream. For example:
 # --deselect=tests/integration/api_container_test.py::AttachContainerTest::test_attach_no_stream
 # TODO re-enable test after https://github.com/docker/docker-py/issues/2513 has been resolved
-: "${PY_TEST_OPTIONS:=--junitxml=${DEST}/junit-report.xml --deselect=tests/integration/api_container_test.py::AttachContainerTest::test_attach_no_stream}"
+: "${PY_TEST_OPTIONS:=--junitxml=${DEST}/junit-report.xml --deselect=tests/integration/api_container_test.py::AttachContainerTest::test_attach_no_stream --deselect=tests/integration/api_container_test.py::CreateContainerTest::test_invalid_log_driver_raises_exception}"
 (
 	bundle .integration-daemon-start