diff --git a/cmd/drone-docker-gcr/main.go b/cmd/drone-docker-gcr/main.go
index 7342de3..b4bc5f8 100644
--- a/cmd/drone-docker-gcr/main.go
+++ b/cmd/drone-docker-gcr/main.go
@@ -8,12 +8,19 @@ import (
 	"strings"
 )
 
+// gcr default username
+const username = "_json_key"
+
 func main() {
 	var (
-		username = "_json_key"
-		password = os.Getenv("GCR_TOKEN")
-		registry = os.Getenv("PLUGIN_REGISTRY")
-		repo     = os.Getenv("PLUGIN_REPO")
+		repo     = getenv("PLUGIN_REPO")
+		registry = getenv("PLUGIN_REGISTRY")
+		password = getenv(
+			"PLUGIN_JSON_KEY",
+			"GCR_JSON_KEY",
+			"GOOGLE_CREDENTIALS",
+			"GOOGLE_APPLICATION_CREDENTIALS",
+		)
 	)
 
 	// decode the token if base64 encoded
@@ -32,9 +39,9 @@ func main() {
 	// should prepend.
 	if !strings.HasPrefix(repo, registry) {
 		repo = path.Join(registry, repo)
-		os.Setenv("PLUGIN_REPO", repo)
 	}
 
+	os.Setenv("PLUGIN_REPO", repo)
 	os.Setenv("PLUGIN_REGISTRY", registry)
 	os.Setenv("DOCKER_USERNAME", username)
 	os.Setenv("DOCKER_PASSWORD", password)
@@ -48,3 +55,13 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+func getenv(key ...string) (s string) {
+	for _, k := range key {
+		s = os.Getenv(k)
+		if s != "" {
+			return
+		}
+	}
+	return
+}
diff --git a/cmd/drone-docker-heroku/main.go b/cmd/drone-docker-heroku/main.go
index 5d8a616..57a2ae8 100644
--- a/cmd/drone-docker-heroku/main.go
+++ b/cmd/drone-docker-heroku/main.go
@@ -9,22 +9,14 @@ import (
 func main() {
 	var (
 		registry = "registry.heroku.com"
-		process  = os.Getenv("PLUGIN_PROCESS_TYPE")
-		app      = os.Getenv("PLUGIN_APP")
-		email    = os.Getenv("PLUGIN_EMAIL")
-		key      = os.Getenv("PLUGIN_API_KEY")
+		process  = getenv("PLUGIN_PROCESS_TYPE")
+		app      = getenv("PLUGIN_APP")
+		email    = getenv("PLUGIN_EMAIL", "HEROKU_EMAIL")
+		key      = getenv("PLUGIN_API_KEY", "HEROKU_API_KEY")
 	)
 
-	// if the heroku email is provided as a named secret
-	// then we should use it.
-	if os.Getenv("HEROKU_EMAIL") != "" {
-		email = os.Getenv("HEROKU_EMAIL")
-	}
-
-	// if the heroku api key is provided as a named secret
-	// then we should use it.
-	if os.Getenv("HEROKU_API_KEY") != "" {
-		key = os.Getenv("HEROKU_API_KEY")
+	if process == "" {
+		process = "web"
 	}
 
 	os.Setenv("PLUGIN_REGISTRY", registry)
@@ -34,7 +26,6 @@ func main() {
 	os.Setenv("DOCKER_USERNAME", email)
 	os.Setenv("DOCKER_EMAIL", email)
 
-	// invoke the base docker plugin binary
 	cmd := exec.Command("drone-docker")
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
@@ -43,3 +34,13 @@ func main() {
 		os.Exit(1)
 	}
 }
+
+func getenv(key ...string) (s string) {
+	for _, k := range key {
+		s = os.Getenv(k)
+		if s != "" {
+			return
+		}
+	}
+	return
+}