Implementation of ListPartitionReassignments API (#1203)

* implemented ListPartitionReassignments API.

* fix nullable

* fix lint

* fix tag.

listpartitionreassignments.go

@@ -0,0 +1,135 @@
+package kafka
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/segmentio/kafka-go/protocol/listpartitionreassignments"
+)
+
+// ListPartitionReassignmentsRequest is a request to the ListPartitionReassignments API.
+type ListPartitionReassignmentsRequest struct {
+	// Address of the kafka broker to send the request to.
+	Addr net.Addr
+
+	// Topics we want reassignments for, mapped by their name, or nil to list everything.
+	Topics map[string]ListPartitionReassignmentsRequestTopic
+
+	// Timeout is the amount of time to wait for the request to complete.
+	Timeout time.Duration
+}
+
+// ListPartitionReassignmentsRequestTopic contains the requested partitions for a single
+// topic.
+type ListPartitionReassignmentsRequestTopic struct {
+	// The partitions to list partition reassignments for.
+	PartitionIndexes []int
+}
+
+// ListPartitionReassignmentsResponse is a response from the ListPartitionReassignments API.
+type ListPartitionReassignmentsResponse struct {
+	// Error is set to a non-nil value including the code and message if a top-level
+	// error was encountered.
+	Error error
+
+	// Topics contains results for each topic, mapped by their name.
+	Topics map[string]ListPartitionReassignmentsResponseTopic
+}
+
+// ListPartitionReassignmentsResponseTopic contains the detailed result of
+// ongoing reassignments for a topic.
+type ListPartitionReassignmentsResponseTopic struct {
+	// Partitions contains result for topic partitions.
+	Partitions []ListPartitionReassignmentsResponsePartition
+}
+
+// ListPartitionReassignmentsResponsePartition contains the detailed result of
+// ongoing reassignments for a single partition.
+type ListPartitionReassignmentsResponsePartition struct {
+	// PartitionIndex contains index of the partition.
+	PartitionIndex int
+
+	// Replicas contains the current replica set.
+	Replicas []int
+
+	// AddingReplicas contains the set of replicas we are currently adding.
+	AddingReplicas []int
+
+	// RemovingReplicas contains the set of replicas we are currently removing.
+	RemovingReplicas []int
+}
+
+func (c *Client) ListPartitionReassignments(
+	ctx context.Context,
+	req *ListPartitionReassignmentsRequest,
+) (*ListPartitionReassignmentsResponse, error) {
+	apiReq := &listpartitionreassignments.Request{
+		TimeoutMs: int32(req.Timeout.Milliseconds()),
+	}
+
+	for topicName, topicReq := range req.Topics {
+		apiReq.Topics = append(
+			apiReq.Topics,
+			listpartitionreassignments.RequestTopic{
+				Name:             topicName,
+				PartitionIndexes: intToInt32Array(topicReq.PartitionIndexes),
+			},
+		)
+	}
+
+	protoResp, err := c.roundTrip(
+		ctx,
+		req.Addr,
+		apiReq,
+	)
+	if err != nil {
+		return nil, err
+	}
+	apiResp := protoResp.(*listpartitionreassignments.Response)
+
+	resp := &ListPartitionReassignmentsResponse{
+		Error:  makeError(apiResp.ErrorCode, apiResp.ErrorMessage),
+		Topics: make(map[string]ListPartitionReassignmentsResponseTopic),
+	}
+
+	for _, topicResult := range apiResp.Topics {
+		respTopic := ListPartitionReassignmentsResponseTopic{}
+		for _, partitionResult := range topicResult.Partitions {
+			respTopic.Partitions = append(
+				respTopic.Partitions,
+				ListPartitionReassignmentsResponsePartition{
+					PartitionIndex:   int(partitionResult.PartitionIndex),
+					Replicas:         int32ToIntArray(partitionResult.Replicas),
+					AddingReplicas:   int32ToIntArray(partitionResult.AddingReplicas),
+					RemovingReplicas: int32ToIntArray(partitionResult.RemovingReplicas),
+				},
+			)
+		}
+		resp.Topics[topicResult.Name] = respTopic
+	}
+
+	return resp, nil
+}
+
+func intToInt32Array(arr []int) []int32 {
+	if arr == nil {
+		return nil
+	}
+	res := make([]int32, len(arr))
+	for i := range arr {
+		res[i] = int32(arr[i])
+	}
+	return res
+}
+
+func int32ToIntArray(arr []int32) []int {
+	if arr == nil {
+		return nil
+	}
+	res := make([]int, len(arr))
+	for i := range arr {
+		res[i] = int(arr[i])
+	}
+	return res
+}

listpartitionreassignments_test.go

@@ -0,0 +1,50 @@
+package kafka
+
+import (
+	"context"
+	"testing"
+
+	ktesting "github.com/segmentio/kafka-go/testing"
+)
+
+func TestClientListPartitionReassignments(t *testing.T) {
+	if !ktesting.KafkaIsAtLeast("2.4.0") {
+		return
+	}
+
+	ctx := context.Background()
+	client, shutdown := newLocalClient()
+	defer shutdown()
+
+	topic := makeTopic()
+	createTopic(t, topic, 2)
+	defer deleteTopic(t, topic)
+
+	// Can't really get an ongoing partition reassignment with local Kafka, so just do a superficial test here.
+	resp, err := client.ListPartitionReassignments(
+		ctx,
+		&ListPartitionReassignmentsRequest{
+			Topics: map[string]ListPartitionReassignmentsRequestTopic{
+				topic: {PartitionIndexes: []int{0, 1}},
+			},
+		},
+	)
+
+	if err != nil {
+		t.Fatal(err)
+	}
+	if resp.Error != nil {
+		t.Error(
+			"Unexpected error in response",
+			"expected", nil,
+			"got", resp.Error,
+		)
+	}
+	if len(resp.Topics) != 0 {
+		t.Error(
+			"Unexpected length of topic results",
+			"expected", 0,
+			"got", len(resp.Topics),
+		)
+	}
+}

protocol/listpartitionreassignments/listpartitionreassignments.go

@@ -0,0 +1,70 @@
+package listpartitionreassignments
+
+import "github.com/segmentio/kafka-go/protocol"
+
+func init() {
+	protocol.Register(&Request{}, &Response{})
+}
+
+// Detailed API definition: https://kafka.apache.org/protocol#The_Messages_ListPartitionReassignments.
+
+type Request struct {
+	// We need at least one tagged field to indicate that this is a "flexible" message
+	// type.
+	_ struct{} `kafka:"min=v0,max=v0,tag"`
+
+	TimeoutMs int32          `kafka:"min=v0,max=v0"`
+	Topics    []RequestTopic `kafka:"min=v0,max=v0,nullable"`
+}
+
+type RequestTopic struct {
+	// We need at least one tagged field to indicate that this is a "flexible" message
+	// type.
+	_ struct{} `kafka:"min=v0,max=v0,tag"`
+
+	Name             string  `kafka:"min=v0,max=v0"`
+	PartitionIndexes []int32 `kafka:"min=v0,max=v0"`
+}
+
+func (r *Request) ApiKey() protocol.ApiKey {
+	return protocol.ListPartitionReassignments
+}
+
+func (r *Request) Broker(cluster protocol.Cluster) (protocol.Broker, error) {
+	return cluster.Brokers[cluster.Controller], nil
+}
+
+type Response struct {
+	// We need at least one tagged field to indicate that this is a "flexible" message
+	// type.
+	_ struct{} `kafka:"min=v0,max=v0,tag"`
+
+	ThrottleTimeMs int32           `kafka:"min=v0,max=v0"`
+	ErrorCode      int16           `kafka:"min=v0,max=v0"`
+	ErrorMessage   string          `kafka:"min=v0,max=v0,nullable"`
+	Topics         []ResponseTopic `kafka:"min=v0,max=v0"`
+}
+
+type ResponseTopic struct {
+	// We need at least one tagged field to indicate that this is a "flexible" message
+	// type.
+	_ struct{} `kafka:"min=v0,max=v0,tag"`
+
+	Name       string              `kafka:"min=v0,max=v0"`
+	Partitions []ResponsePartition `kafka:"min=v0,max=v0"`
+}
+
+type ResponsePartition struct {
+	// We need at least one tagged field to indicate that this is a "flexible" message
+	// type.
+	_ struct{} `kafka:"min=v0,max=v0,tag"`
+
+	PartitionIndex   int32   `kafka:"min=v0,max=v0"`
+	Replicas         []int32 `kafka:"min=v0,max=v0"`
+	AddingReplicas   []int32 `kafka:"min=v0,max=v0"`
+	RemovingReplicas []int32 `kafka:"min=v0,max=v0"`
+}
+
+func (r *Response) ApiKey() protocol.ApiKey {
+	return protocol.ListPartitionReassignments
+}

protocol/listpartitionreassignments/listpartitionreassignments_test.go

@@ -0,0 +1,41 @@
+package listpartitionreassignments_test
+
+import (
+	"testing"
+
+	"github.com/segmentio/kafka-go/protocol/listpartitionreassignments"
+	"github.com/segmentio/kafka-go/protocol/prototest"
+)
+
+const (
+	v0 = 0
+)
+
+func TestListPartitionReassignmentsRequest(t *testing.T) {
+	prototest.TestRequest(t, v0, &listpartitionreassignments.Request{
+		Topics: []listpartitionreassignments.RequestTopic{
+			{
+				Name:             "topic-1",
+				PartitionIndexes: []int32{1, 2, 3},
+			},
+		},
+	})
+}
+
+func TestListPartitionReassignmentsResponse(t *testing.T) {
+	prototest.TestResponse(t, v0, &listpartitionreassignments.Response{
+		Topics: []listpartitionreassignments.ResponseTopic{
+			{
+				Name: "topic-1",
+				Partitions: []listpartitionreassignments.ResponsePartition{
+					{
+						PartitionIndex:   1,
+						Replicas:         []int32{1, 2, 3},
+						AddingReplicas:   []int32{4, 5, 6},
+						RemovingReplicas: []int32{7, 8, 9},
+					},
+				},
+			},
+		},
+	})
+}