doc: add http api doc (#805)

docs/binlog_http_api.md

@@ -0,0 +1,188 @@
+# TiDB-Binlog HTTP API
+
+## Pump
+
+`PumpIP` is the ip of the Pump server. `8250` is the default port of Pump.
+
+1. Get the current status of Pump instances
+
+    ```shell
+    curl http://{PumpIP}:8250/status
+    ```
+
+    ```shell
+    $curl http://127.0.0.1:8250/status
+
+   {
+       "status":{
+           "ip-172-16-5-71:8250":{
+               "nodeId":"ip-172-16-5-71:8250",
+               "host":"172.16.5.71:8250",
+               "state":"online",
+               "isAlive":false,
+               "score":0,
+               "label":null,
+               "maxCommitTS":412518831548007863,
+               "updateTS":412518831338292471
+           },
+           "ip-172-16-5-74:8250":{
+               "nodeId":"ip-172-16-5-74:8250",
+               "host":"172.16.5.74:8250",
+               "state":"online",
+               "isAlive":false,
+               "score":0,
+               "label":null,
+               "maxCommitTS":412518831548007869,
+               "updateTS":412518831325184860
+           },
+           "ip-172-16-5-75:8250":{
+               "nodeId":"ip-172-16-5-75:8250",
+               "host":"172.16.5.75:8250",
+               "state":"online",
+               "isAlive":false,
+               "score":0,
+               "label":null,
+               "maxCommitTS":412518831548007875,
+               "updateTS":412518831534899704
+           }
+       },
+       "CommitTS":412518831849473230,
+       "Checkpoint":{
+   
+       },
+       "ErrMsg":""
+   }
+    ```
+
+1. Get all metrics of Pump
+
+    ```shell
+    curl http://{PumpIP}:8250/metrics
+    ```
+
+1. Get the status of all drainers
+
+    ```shell
+    curl http://{PumpIP}:8250/drainers
+    ```
+
+    ```shell
+    $curl http://127.0.0.1:8250/drainers
+
+   [
+       {
+           "nodeId":"ip-172-16-5-70:8249",
+           "host":"172.16.5.70:8249",
+           "state":"paused",
+           "isAlive":false,
+           "score":0,
+           "label":null,
+           "maxCommitTS":412361808537191540,
+           "updateTS":412518474704487076
+       }
+   ]
+    ```
+1. Change the Pump status
+
+    `NodeID` is the node id of the Pump server. `Action` is the action to execute[possible values: `pause`, `close`].
+    `pause` is equivalent to `pause-pump` in [binlogctl](https://github.com/pingcap/tidb-binlog/tree/master/binlogctl), `close` is equivalent to `offline-pump` in [binlogctl](https://github.com/pingcap/tidb-binlog/tree/master/binlogctl).
+
+    ```shell
+    curl -X PUT http://{PumpIP}:8250/state/{NodeID}/{Action}
+    ```
+
+    ```shell
+    $curl -X PUT http://127.0.0.1:8250/state/ip-172-16-5-71:8250/stop
+    
+    {
+        "message":"apply action stop success!",
+        "code":200
+    }
+    ```
+
+1. Get the binlog by TS
+
+   ```shell
+    curl http://{PumpIP}:8250/debug/binlog/{ts}
+   ```
+
+   ```shell
+   $curl http://127.0.0.1:8250/debug/binlog/412518831548007863
+   
+    tp:Commit start_ts:412518831548007786 commit_ts:412518831548007863 prewrite_key:"t\200\000\000\000\000\000-\212_i\200\000\000\000\000\000\000\001\003\200\000\000\000\000\teK\003\200\000\000\000\000\007\230L"
+    
+     GetMvccByEncodedKey:
+   ```
+
+1. Start the GC
+
+   ```shell
+    curl -X POST http://{PumpIP}:8250/debug/gc/trigger
+   ```
+
+## Drainer
+
+ `DrainerIP` is the ip of the Drainer server. `8249` is the default port of Drainer.
+
+1. Get the current status of Drainer
+
+   ```shell
+    curl http://{DrainerIP}:8249/status
+   ```
+
+   ```shell
+   $curl http://127.0.0.1:8249/status
+   
+    {
+        "PumpPos":{
+            "ip-172-16-5-71:8250":412361808550297954,
+            "ip-172-16-5-74:8250":412361808550297951,
+            "ip-172-16-5-75:8250":412361808550297952
+        },
+        "Synced":true,
+        "LastTS":412361808537191540,
+        "TsMap":""
+    }
+   ```
+
+1. Get all metrics of Drainer
+
+    ```shell
+    curl http://{DrainerIP}:8249/metrics
+    ```
+
+1. Get the lastest commit ts of Drainer
+
+   ```shell
+    curl http://{DrainerIP}:8249/commit_ts
+   ```
+
+   ```shell
+   $curl http://127.0.0.1:8249/status
+   
+    {
+      "message": "get drainer's latest ts success!",
+      "code": 200,
+      "data": {
+        "ts": 412361808537191540
+      }
+    }
+   ```
+
+1. Change the Drainer status
+
+    `NodeID` is the node id of the Drainer server. `Action` is the action to execute[possible values: `pause`, `close`].
+    `pause` is equivalent to `pause-drainer` in [binlogctl](https://github.com/pingcap/tidb-binlog/tree/master/binlogctl), `close` is equivalent to `offline-drainer` in [binlogctl](https://github.com/pingcap/tidb-binlog/tree/master/binlogctl).
+
+    ```shell
+    curl -X PUT http://{DrainerIP}:8249/state/{NodeID}/{Action}
+    ```
+
+    ```shell
+    $curl -X PUT http://127.0.0.1:8249/state/ip-172-16-5-70:8249/stop
+    
+    {
+        "message":"apply action stop success!",
+        "code":200
+    }
+    ```