Fix a metric-related bug in etcd/client (pingcap#4267)

close pingcap#4266

pkg/etcd/client.go

@@ -114,10 +114,10 @@ func (c *Client) Get(ctx context.Context, key string, opts ...clientv3.OpOption)
 
 // Delete delegates request to clientv3.KV.Delete
 func (c *Client) Delete(ctx context.Context, key string, opts ...clientv3.OpOption) (resp *clientv3.DeleteResponse, err error) {
-	if metric, ok := c.metrics[EtcdTxn]; ok {
+	if metric, ok := c.metrics[EtcdDel]; ok {
 		metric.Inc()
 	}
-	// We don't retry on delete operatoin. It's dangerous.
+	// We don't retry on delete operation. It's dangerous.
 	return c.cli.Delete(ctx, key, opts...)
 }
 

pkg/orchestrator/etcd_worker.go

@@ -39,8 +39,8 @@ const (
 	// etcdTxnTimeoutDuration represents the timeout duration for committing a
 	// transaction to Etcd
 	etcdTxnTimeoutDuration = 30 * time.Second
-	// etcdWorkerLogsWarnDuration when EtcdWorker commits a txn to etcd or ticks
-	// it reactor takes more than etcdWorkerLogsWarnDuration, it will print a log
+	// When EtcdWorker commits a txn to etcd or ticks its reactor
+	// takes more than etcdWorkerLogsWarnDuration, it will print a log
 	etcdWorkerLogsWarnDuration = 1 * time.Second
 	deletionCounterKey         = "/meta/ticdc-delete-etcd-key-count"
 )

pkg/pipeline/context.go

@@ -15,7 +15,7 @@ package pipeline
 
 import "github.com/pingcap/tiflow/pkg/context"
 
-// NodeContext adds two functions from `coutext.Context` and created by pipeline
+// NodeContext adds two functions to `context.Context` and is created by pipeline
 type NodeContext interface {
 	context.Context