From 934bed47faef699b125a95355581d4a20939ee61 Mon Sep 17 00:00:00 2001
From: Poorna Krishnamoorthy <poornas@users.noreply.github.com>
Date: Mon, 7 Dec 2020 13:53:28 -0800
Subject: [PATCH] Add transition event notification (#11047)

This is a MinIO specific extension to allow monitoring of transition events.
---
 cmd/bucket-lifecycle.go         | 20 ++++++++++++++++----
 docs/bucket/lifecycle/README.md |  5 +++++
 pkg/event/name.go               | 21 ++++++++++++++++++++-
 3 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/cmd/bucket-lifecycle.go b/cmd/bucket-lifecycle.go
index d67dc2d71..3bdceee05 100644
--- a/cmd/bucket-lifecycle.go
+++ b/cmd/bucket-lifecycle.go
@@ -356,11 +356,23 @@ func transitionObject(ctx context.Context, objectAPI ObjectLayer, objInfo Object
 	opts.Versioned = globalBucketVersioningSys.Enabled(oi.Bucket)
 	opts.VersionID = oi.VersionID
 	opts.TransitionStatus = lifecycle.TransitionComplete
+	eventName := event.ObjectTransitionComplete
 
-	if _, err = objectAPI.DeleteObject(ctx, oi.Bucket, oi.Name, opts); err != nil {
-		return err
-	}
-	return nil
+	_, err = objectAPI.DeleteObject(ctx, oi.Bucket, oi.Name, opts)
+	if err != nil {
+		eventName = event.ObjectTransitionFailed
+	}
+	// Notify object deleted event.
+	sendEvent(eventArgs{
+		EventName:  eventName,
+		BucketName: oi.Bucket,
+		Object: ObjectInfo{
+			Name:      oi.Name,
+			VersionID: opts.VersionID,
+		},
+		Host: "Internal: [ILM-Transition]",
+	})
+	return err
 }
 
 // getLifecycleTransitionTargetArn returns transition ARN for storage class specified in the config.
diff --git a/docs/bucket/lifecycle/README.md b/docs/bucket/lifecycle/README.md
index 8e1894837..a92314996 100644
--- a/docs/bucket/lifecycle/README.md
+++ b/docs/bucket/lifecycle/README.md
@@ -127,6 +127,11 @@ aws s3api restore-object --bucket srcbucket \
 --restore-request Days=3
 ```
 
+### 4.1 Monitoring transition events
+`s3:ObjectTransition:Complete` and `s3:ObjectTransition:Failed` events can be used to monitor transition events between the source cluster and transition tier. To watch lifecycle events, you can enable bucket notification on the source bucket with `mc event add`  and specify `--event ilm` flag.
+
+Note that transition event notification is a MinIO extension.
+
 ## Explore Further
 - [MinIO | Golang Client API Reference](https://docs.min.io/docs/golang-client-api-reference.html#SetBucketLifecycle)
 - [Object Lifecycle Management](https://docs.aws.amazon.com/AmazonS3/latest/dev/object-lifecycle-mgmt.html)
diff --git a/pkg/event/name.go b/pkg/event/name.go
index 6f5a108f7..5ec7afc76 100644
--- a/pkg/event/name.go
+++ b/pkg/event/name.go
@@ -55,6 +55,9 @@ const (
 	ObjectRestorePostInitiated
 	ObjectRestorePostCompleted
 	ObjectRestorePostAll
+	ObjectTransitionAll
+	ObjectTransitionFailed
+	ObjectTransitionComplete
 )
 
 // Expand - returns expanded values of abbreviated event type.
@@ -94,6 +97,11 @@ func (name Name) Expand() []Name {
 			ObjectRestorePostInitiated,
 			ObjectRestorePostCompleted,
 		}
+	case ObjectTransitionAll:
+		return []Name{
+			ObjectTransitionFailed,
+			ObjectTransitionComplete,
+		}
 	default:
 		return []Name{name}
 	}
@@ -152,6 +160,12 @@ func (name Name) String() string {
 		return "s3:ObjectRestore:Post"
 	case ObjectRestorePostCompleted:
 		return "s3:ObjectRestore:Completed"
+	case ObjectTransitionAll:
+		return "s3:ObjectTransition:*"
+	case ObjectTransitionFailed:
+		return "s3:ObjectTransition:Failed"
+	case ObjectTransitionComplete:
+		return "s3:ObjectTransition:Complete"
 	}
 
 	return ""
@@ -254,7 +268,12 @@ func ParseName(s string) (Name, error) {
 		return ObjectRestorePostInitiated, nil
 	case "s3:ObjectRestore:Completed":
 		return ObjectRestorePostCompleted, nil
-
+	case "s3:ObjectTransition:Failed":
+		return ObjectTransitionFailed, nil
+	case "s3:ObjectTransition:Complete":
+		return ObjectTransitionComplete, nil
+	case "s3:ObjectTransition:*":
+		return ObjectTransitionAll, nil
 	default:
 		return 0, &ErrInvalidEventName{s}
 	}