Add ChangeTabletTags and ChangeTags RPCs

Signed-off-by: Tim Vaillancourt <[email protected]>

changelog/21.0/21.0.0/summary.md

@@ -18,6 +18,7 @@
     - **[Dynamic VReplication Configuration](#dynamic-vreplication-configuration)**
     - **[Reference Table Materialization](#reference-table-materialization)**
     - **[New VEXPLAIN Modes: TRACE and KEYS](#new-vexplain-modes)**
+    - **[vtctldclient ChangeTabletTags](#vtctldclient-changetablettags)**
 
 ## <a id="major-changes"/>Major Changes
 
@@ -197,3 +198,22 @@ The KEYS mode for VEXPLAIN offers a concise summary of query structure, highligh
 KEYS mode analyzes the query structure without executing it, providing JSON output that includes grouping columns, join columns, filter columns (potential candidates for indexes, primary keys, or sharding keys), and the statement type.
 
 These new VEXPLAIN modes enhance Vitess's query analysis capabilities, allowing for more informed decisions about sharding strategies and query optimization.
+
+### <a id="vtctldclient-changetablettags"/>`vtctldclient ChangeTabletTags` command and RPCs
+
+The `vtctldclient` command `ChangeTabletTags` was added to allow the tags of a tablet to be changed dynamically.
+
+This command allows one or many tablet tags to be defined using key=value format. The provided tags are merged with existing tags by default. The optional flag `--replace` causes the existing tags to be replaced with the provided tags. To support this, the VTCtld RPC `ChangeTabletTags` and the VTTablet RPC `ChangeTags` were added.
+
+Previous to this release the only way to define tablet tags was the `--init_tags` flag of `vttablet`, which requires a restart for a change to take effect.
+
+Example:
+```bash
+$ vtctldclient $FLAGS ChangeTabletTags --replace zone1-100 hello=world
+- []
++ [hello: "world"]
+$ vtctldclient $FLAGS GetTablet zone1-100 | jq .tags
+{
+  "hello": "world"
+}
+```

go/cmd/vtctldclient/cli/tablets.go

@@ -17,9 +17,11 @@ limitations under the License.
 package cli
 
 import (
-	"vitess.io/vitess/go/vt/topo/topoproto"
+	"fmt"
+	"strings"
 
 	topodatapb "vitess.io/vitess/go/vt/proto/topodata"
+	"vitess.io/vitess/go/vt/topo/topoproto"
 )
 
 // TabletAliasesFromPosArgs takes a list of positional (non-flag) arguments and
@@ -38,3 +40,22 @@ func TabletAliasesFromPosArgs(args []string) ([]*topodatapb.TabletAlias, error)
 
 	return aliases, nil
 }
+
+// TabletTagsFromPosArgs takes a list of positional (non-flag) arguements and
+// converts them to a map of tablet tags.
+func TabletTagsFromPosArgs(args []string) (map[string]string, error) {
+	if len(args) == 0 {
+		return nil, fmt.Errorf("no tablet tags specified")
+	}
+
+	tags := make(map[string]string, len(args))
+	for _, kvPair := range args {
+		if !strings.Contains(kvPair, "=") {
+			return nil, fmt.Errorf("invalid tablet tag %q specified. tablet tags must be specified in key=value format", kvPair)
+		}
+		fields := strings.SplitN(kvPair, "=", 2)
+		tags[fields[0]] = fields[1]
+	}
+
+	return tags, nil
+}

go/cmd/vtctldclient/cli/tablets_test.go

@@ -0,0 +1,48 @@
+/*
+Copyright 2024 The Vitess 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 cli
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTabletTagsFromPosArgs(t *testing.T) {
+	t.Parallel()
+
+	{
+		tags, err := TabletTagsFromPosArgs([]string{"fail"})
+		assert.Error(t, err)
+		assert.Nil(t, tags)
+	}
+	{
+		tags, err := TabletTagsFromPosArgs([]string{"hello=world"})
+		assert.NoError(t, err)
+		assert.Equal(t, map[string]string{
+			"hello": "world",
+		}, tags)
+	}
+	{
+		tags, err := TabletTagsFromPosArgs([]string{"hello=world", "test=123"})
+		assert.NoError(t, err)
+		assert.Equal(t, map[string]string{
+			"hello": "world",
+			"test":  "123",
+		}, tags)
+	}
+}

go/cmd/vtctldclient/command/tablets.go

@@ -34,6 +34,17 @@ import (
 )
 
 var (
+	// ChangeTabletTags makes a ChangeTabletTags gRPC call to a vtctld.
+	ChangeTabletTags = &cobra.Command{
+		Use:   "ChangeTabletTags <alias> <tablet-tag> [ <tablet-tag> ... ]",
+		Short: "Changes the tablet tags for the specified tablet, if possible.",
+		Long: `Changes the tablet tags for the specified tablet, if possible.
+
+Tags must be specified as key=value pairs.`,
+		DisableFlagsInUseLine: true,
+		Args:                  cobra.MinimumNArgs(2),
+		RunE:                  commandChangeTabletTags,
+	}
 	// ChangeTabletType makes a ChangeTabletType gRPC call to a vtctld.
 	ChangeTabletType = &cobra.Command{
 		Use:   "ChangeTabletType [--dry-run] <alias> <tablet-type>",
@@ -212,6 +223,40 @@ Note that, in the SleepTablet implementation, the value should be positively-sig
 	}
 )
 
+var changeTabletTagsOptions = struct {
+	Replace bool
+}{}
+
+func commandChangeTabletTags(cmd *cobra.Command, args []string) error {
+	allArgs := cmd.Flags().Args()
+
+	alias, err := topoproto.ParseTabletAlias(allArgs[0])
+	if err != nil {
+		return err
+	}
+
+	tags, err := cli.TabletTagsFromPosArgs(allArgs[1:])
+	if err != nil {
+		return err
+	}
+
+	cli.FinishedParsing(cmd)
+
+	resp, err := client.ChangeTabletTags(commandCtx, &vtctldatapb.ChangeTabletTagsRequest{
+		TabletAlias: alias,
+		Tags:        tags,
+		Replace:     changeTabletTagsOptions.Replace,
+	})
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("- %v\n", cli.MarshalMapAWK(resp.BeforeTags))
+	fmt.Printf("+ %v\n", cli.MarshalMapAWK(resp.AfterTags))
+
+	return nil
+}
+
 var changeTabletTypeOptions = struct {
 	DryRun bool
 }{}
@@ -629,6 +674,9 @@ func commandStopReplication(cmd *cobra.Command, args []string) error {
 }
 
 func init() {
+	ChangeTabletTags.Flags().BoolVarP(&changeTabletTagsOptions.Replace, "replace", "r", false, "Replace all tablet tags with the tags provided. By default tags are merged/updated.")
+	Root.AddCommand(ChangeTabletTags)
+
 	ChangeTabletType.Flags().BoolVarP(&changeTabletTypeOptions.DryRun, "dry-run", "d", false, "Shows the proposed change without actually executing it.")
 	Root.AddCommand(ChangeTabletType)
 

go/flags/endtoend/vtctldclient.txt

@@ -18,6 +18,7 @@ Available Commands:
   ApplyVSchema                Applies the VTGate routing schema to the provided keyspace. Shows the result after application.
   Backup                      Uses the BackupStorage service on the given tablet to create and store a new backup.
   BackupShard                 Finds the most up-to-date REPLICA, RDONLY, or SPARE tablet in the given shard and uses the BackupStorage service on that tablet to create and store a new backup.
+  ChangeTabletTags            Changes the tablet tags for the specified tablet, if possible.
   ChangeTabletType            Changes the db type for the specified tablet, if possible.
   CheckThrottler              Issue a throttler check on the given tablet.
   CreateKeyspace              Creates the specified keyspace in the topology.