metrics/grafana: use jsonnet to generate tidb-summary Grafana json fi…

…les (pingcap#32333)

ref pingcap#32194

Makefile

@@ -417,3 +417,6 @@ dumpling_bins:
 
 tools/bin/gotestsum: tools/check/go.mod
 	cd tools/check && $(GO) build -o ../bin/gotestsum gotest.tools/gotestsum
+
+generate_grafana_scripts:
+	@cd metrics/grafana && mv tidb_summary.json tidb_summary.json.committed && ./generate_json.sh && diff -u tidb_summary.json.committed tidb_summary.json && rm tidb_summary.json.committed

metrics/grafana/README.md

@@ -0,0 +1,14 @@
+## About
+
+Use [jsonnet](https://github.com/google/go-jsonnet) to generate Grafana-compliant json scripts for use with TiDB.
+
+Why jsonnet?
+
+1. jsonnet is a DSL created by Google for json, which is good for advanced json editing work.
+2. Grafana provides the [jsonnet library](https://grafana.github.io/grafonnet-lib/) specifically for generating Grafana json, which makes maintaining TiDB's json scripts much easier.
+
+## Usage
+
+1. Modify the jsonnet files (e.g. tidb_summary.jsonnet).
+2. Run `generate_json.sh` to generate the json files by the jsonnet files.
+3. Commit the modifications.

metrics/grafana/generate_json.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+# Copyright 2022 PingCAP, Inc.
+#
+# 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.
+
+go install github.com/google/go-jsonnet/cmd/jsonnet@latest
+git clone https://github.com/grafana/grafonnet-lib.git
+
+export JSONNET_PATH=grafonnet-lib
+jsonnet tidb_summary.jsonnet > tidb_summary.json
+rm -rf $JSONNET_PATH
+