Fixes#4813
If a TopicConfiguration element or CloudFunction element is found in
configuration submitted to PutBucketNotification API, an BadRequest
error is returned.
This is an enhancement change to to cater support all
the data fields present on the object. Currently
we only send a subset of data which object info
provides us.
It also helps us keep a full namespace mirror on
notification targets for efficient query.
This change adds information like host, port and user-agent of the
client whose request triggered an event notification.
E.g, if someone uploads an object to a bucket using mc. If notifications
were configured on that bucket, the host, port and user-agent of mc
would be sent as part of event notification data.
Sample output:
```
"source": {
"host": "127.0.0.1",
"port": "55808",
"userAgent": "Minio (linux; amd64) minio-go/2.0.4 mc ..."
}
```
`principalId` i.e user identity is kept as AccessKey in
accordance with S3 spec.
Additionally responseElements{} are added starting with
`x-amz-request-id` is a hexadecimal of the event time itself in nanosecs.
`x-minio-origin-server` - points to the server generating the event.
Fixes#3556
* Implements a Peer RPC router that sends info to all Minio servers in the cluster.
* Bucket notifications are propagated to all nodes via this RPC router.
* Bucket listener configuration is persisted to separate object layer
file (`listener.json`) and peer RPCs are used to communicate changes
throughout the cluster.
* When events are generated, RPC calls to send them to other servers
where bucket listeners may be connected is implemented.
* Some bucket notification tests are now disabled as they cannot work in
the new design.
* Minor fix in `funcFromPC` to use `path.Join`
Aditya Manthramurthy
Harshavardhana
Krishnan Parthasarathi