Check Google logging client pointer for nil before calling Close() (#321

)

* check if client pointer is nil before attempting to call Close()

* Resolve panic during shutdown when Google Cloud Output credential file not found

* prepend 'fixed'

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Fixed
+- Fixed panic during shutdown when Google Cloud Output credential file not found [Issue 264](https://github.com/observIQ/stanza/issues/264)
+
 ## [1.0.0] - 2021-05-27
 
 ### Changed

operator/builtin/output/googlecloud/google_cloud.go

@@ -195,7 +195,10 @@ func (g *GoogleCloudOutput) Stop() error {
 	if err := g.buffer.Close(); err != nil {
 		return err
 	}
-	return g.client.Close()
+	if g.client != nil {
+		return g.client.Close()
+	}
+	return nil
 }
 
 // Process processes an entry