Backend image rendering as plugin (#11966)

* rendering: headless chrome progress

* renderer: minor change

* grpc: version hell

* updated grpc libs

* wip: minor progess

* rendering: new image rendering plugin is starting to work

* feat: now phantomjs works as well and updated alerting to use new rendering service

* refactor: renamed renderer package and service to rendering to make renderer name less confusing (rendering is internal service that handles the renderer plugin now)

* rendering: now render key is passed and render auth is working in plugin mode

* removed unneeded lines from gitignore

* rendering: now plugin mode supports waiting for all panels to complete rendering

* fix: LastSeenAt fix for render calls, was not set which causes a lot of updates to Last Seen at during rendering, this should fix sqlite db locked issues in seen in previous releases

* change: changed render tz url parameter to use proper timezone name as chrome does not handle UTC offset TZ values

* fix: another update to tz param generation

* renderer: added http mode to renderer service, new ini setting [rendering] server_url

vendor/github.com/prometheus/procfs/fs.go

@@ -1,3 +1,16 @@
+// Copyright 2018 The Prometheus 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 procfs
 
 import (
@@ -5,7 +18,7 @@ import (
 	"os"
 	"path"
 
-	"github.com/prometheus/procfs/nfsd"
+	"github.com/prometheus/procfs/nfs"
 	"github.com/prometheus/procfs/xfs"
 )
 
@@ -46,13 +59,24 @@ func (fs FS) XFSStats() (*xfs.Stats, error) {
 	return xfs.ParseStats(f)
 }
 
-// NFSdRPCStats retrieves NFS daemon RPC statistics.
-func (fs FS) NFSdRPCStats() (*nfsd.RPCStats, error) {
+// NFSClientRPCStats retrieves NFS client RPC statistics.
+func (fs FS) NFSClientRPCStats() (*nfs.ClientRPCStats, error) {
+	f, err := os.Open(fs.Path("net/rpc/nfs"))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return nfs.ParseClientRPCStats(f)
+}
+
+// NFSdServerRPCStats retrieves NFS daemon RPC statistics.
+func (fs FS) NFSdServerRPCStats() (*nfs.ServerRPCStats, error) {
 	f, err := os.Open(fs.Path("net/rpc/nfsd"))
 	if err != nil {
 		return nil, err
 	}
 	defer f.Close()
 
-	return nfsd.ParseRPCStats(f)
+	return nfs.ParseServerRPCStats(f)
 }