Add constants that define the Event metadata conventions

Signed-off-by: Stefan Prodan <[email protected]>

apis/event/v1beta1/metadata.go

@@ -0,0 +1,30 @@
+/*
+Copyright 2022 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1beta1
+
+// These constants define the Event metadata keys used throughout Flux controllers.
+const (
+	// MetaRevisionKey is the key used to hold the source artifact revision.
+	MetaRevisionKey string = "revision"
+	// MetaChecksumKey is the key used to hold the source artifact checksum.
+	MetaChecksumKey string = "checksum"
+	// MetaCommitStatusKey is the key used to signal a Git commit status event.
+	MetaCommitStatusKey string = "commit_status"
+	// MetaCommitStatusUpdateValue is the value of MetaCommitStatusKey
+	// used to signal a Git commit status update.
+	MetaCommitStatusUpdateValue string = "update"
+)