forked from confluentinc/confluent-kafka-go
/
go_verifiable_consumer.go
440 lines (356 loc) · 11.4 KB
/
go_verifiable_consumer.go
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// Apache Kafka kafkatest VerifiableConsumer implemented in Go
package main
/**
* Copyright 2016 Confluent 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.
*/
import (
"encoding/json"
"fmt"
"github.com/confluentinc/confluent-kafka-go/kafka"
"gopkg.in/alecthomas/kingpin.v2"
"os"
"os/signal"
"strings"
"syscall"
"time"
)
var (
verbosity = 1
sigs chan os.Signal
)
func fatal(why string) {
fmt.Fprintf(os.Stderr, "%% FATAL ERROR: %s", why)
panic(why)
}
func send(name string, msg map[string]interface{}) {
if msg == nil {
msg = make(map[string]interface{})
}
msg["name"] = name
msg["_time"] = time.Now().Unix()
b, err := json.Marshal(msg)
if err != nil {
fatal(fmt.Sprintf("json.Marshal failed: %v", err))
}
fmt.Println(string(b))
}
func partitionsToMap(partitions []kafka.TopicPartition) []map[string]interface{} {
parts := make([]map[string]interface{}, len(partitions))
for i, tp := range partitions {
parts[i] = map[string]interface{}{"topic": *tp.Topic, "partition": tp.Partition, "offset": tp.Offset}
}
return parts
}
func sendOffsetsCommitted(offsets []kafka.TopicPartition, err error) {
if len(state.currAssignment) == 0 {
// Dont emit offsets_committed if there is no current assignment
// This happens when auto_commit is enabled since we also
// force a manual commit on rebalance to make sure
// offsets_committed is emitted prior to partitions_revoked,
// so the builtin auto committer will also kick in and post
// this later OffsetsCommitted event which we simply ignore..
fmt.Fprintf(os.Stderr, "%% Ignore OffsetsCommitted(%v) without a valid assignment\n", err)
return
}
msg := make(map[string]interface{})
if err != nil {
msg["success"] = false
msg["error"] = fmt.Sprintf("%v", err)
kerr, ok := err.(kafka.Error)
if ok && kerr.Code() == kafka.ErrNoOffset {
fmt.Fprintf(os.Stderr, "%% No offsets to commit\n")
return
}
fmt.Fprintf(os.Stderr, "%% Commit failed: %v", msg["error"])
} else {
msg["success"] = true
}
if offsets != nil {
msg["offsets"] = partitionsToMap(offsets)
}
// Make sure we report consumption before commit,
// otherwise tests may fail because of commit > consumed
sendRecordsConsumed(true)
send("offsets_committed", msg)
}
func sendPartitions(name string, partitions []kafka.TopicPartition) {
msg := make(map[string]interface{})
msg["partitions"] = partitionsToMap(partitions)
send(name, msg)
}
type assignedPartition struct {
tp kafka.TopicPartition
consumedMsgs int
minOffset int64
maxOffset int64
}
func assignmentKey(tp kafka.TopicPartition) string {
return fmt.Sprintf("%s-%d", *tp.Topic, tp.Partition)
}
func findAssignment(tp kafka.TopicPartition) *assignedPartition {
a, ok := state.currAssignment[assignmentKey(tp)]
if !ok {
return nil
}
return a
}
func addAssignment(tp kafka.TopicPartition) {
state.currAssignment[assignmentKey(tp)] = &assignedPartition{tp: tp, minOffset: -1, maxOffset: -1}
}
func clearCurrAssignment() {
state.currAssignment = make(map[string]*assignedPartition)
}
type commState struct {
run bool
consumedMsgs int
consumedMsgsLastReported int
consumedMsgsAtLastCommit int
currAssignment map[string]*assignedPartition
maxMessages int
autoCommit bool
asyncCommit bool
c *kafka.Consumer
termOnRevoke bool
}
var state commState
func sendRecordsConsumed(immediate bool) {
if len(state.currAssignment) == 0 ||
(!immediate && state.consumedMsgsLastReported+1000 > state.consumedMsgs) {
return
}
msg := map[string]interface{}{}
msg["count"] = state.consumedMsgs - state.consumedMsgsLastReported
parts := make([]map[string]interface{}, len(state.currAssignment))
i := 0
for _, a := range state.currAssignment {
if a.minOffset == -1 {
// Skip partitions that havent had any messages since last time.
// This is to circumvent some minOffset checks in kafkatest.
continue
}
parts[i] = map[string]interface{}{"topic": *a.tp.Topic,
"partition": a.tp.Partition,
"consumed_msgs": a.consumedMsgs,
"minOffset": a.minOffset,
"maxOffset": a.maxOffset}
a.minOffset = -1
i++
}
msg["partitions"] = parts[0:i]
send("records_consumed", msg)
state.consumedMsgsLastReported = state.consumedMsgs
}
// do_commit commits every 1000 messages or whenever there is a consume timeout, or when immediate==true
func doCommit(immediate bool, async bool) {
if !immediate &&
(state.autoCommit ||
state.consumedMsgsAtLastCommit+1000 > state.consumedMsgs) {
return
}
async = state.asyncCommit
fmt.Fprintf(os.Stderr, "%% Committing %d messages (async=%v)\n",
state.consumedMsgs-state.consumedMsgsAtLastCommit, async)
state.consumedMsgsAtLastCommit = state.consumedMsgs
var waitCommitted chan bool
if !async {
waitCommitted = make(chan bool)
}
go func() {
offsets, err := state.c.Commit()
sendOffsetsCommitted(offsets, err)
if !async {
close(waitCommitted)
}
}()
if !async {
_, _ = <-waitCommitted
}
}
// returns false when consumer should terminate, else true to keep running.
func handleMsg(m *kafka.Message) bool {
if verbosity >= 2 {
fmt.Fprintf(os.Stderr, "%% Message receved: %v:\n", m.TopicPartition)
}
a := findAssignment(m.TopicPartition)
if a == nil {
fmt.Fprintf(os.Stderr, "%% Received message on unassigned partition: %v\n", m.TopicPartition)
return true
}
a.consumedMsgs++
offset := int64(m.TopicPartition.Offset)
if a.minOffset == -1 {
a.minOffset = offset
}
if a.maxOffset < offset {
a.maxOffset = offset
}
state.consumedMsgs++
sendRecordsConsumed(false)
doCommit(false, state.asyncCommit)
if state.maxMessages > 0 && state.consumedMsgs >= state.maxMessages {
// ignore extra messages
return false
}
return true
}
// handle_event handles an event as returned by Poll().
func handleEvent(c *kafka.Consumer, ev kafka.Event) {
switch e := ev.(type) {
case kafka.AssignedPartitions:
if len(state.currAssignment) > 0 {
fatal(fmt.Sprintf("Assign: currAssignment should have been empty: %v", state.currAssignment))
}
state.currAssignment = make(map[string]*assignedPartition)
for _, tp := range e.Partitions {
addAssignment(tp)
}
sendPartitions("partitions_assigned", e.Partitions)
c.Assign(e.Partitions)
case kafka.RevokedPartitions:
sendRecordsConsumed(true)
doCommit(true, false)
sendPartitions("partitions_revoked", e.Partitions)
clearCurrAssignment()
c.Unassign()
if state.termOnRevoke {
state.run = false
}
case kafka.OffsetsCommitted:
sendOffsetsCommitted(e.Offsets, e.Error)
case *kafka.Message:
state.run = handleMsg(e)
case kafka.Error:
if e.Code() == kafka.ErrUnknownTopicOrPart {
fmt.Fprintf(os.Stderr,
"%% Ignoring transient error: %v\n", e)
} else {
fatal(fmt.Sprintf("%% Error: %v\n", e))
}
default:
fmt.Fprintf(os.Stderr, "%% Unhandled event %T ignored: %v\n", e, e)
}
}
// main_loop serves consumer events, signals, etc.
// will run for at most (roughly) \p timeout seconds.
func mainLoop(c *kafka.Consumer, timeout int) {
tmout := time.NewTicker(time.Duration(timeout) * time.Second)
every1s := time.NewTicker(1 * time.Second)
out:
for state.run == true {
select {
case _ = <-tmout.C:
tmout.Stop()
break out
case sig := <-sigs:
fmt.Fprintf(os.Stderr, "%% Terminating on signal %v\n", sig)
state.run = false
case _ = <-every1s.C:
// Report consumed messages
sendRecordsConsumed(true)
// Commit on timeout as well (not just every 1000 messages)
doCommit(false, state.asyncCommit)
default:
//case _ = <-time.After(100000 * time.Microsecond):
for true {
ev := c.Poll(0)
if ev == nil {
break
}
handleEvent(c, ev)
}
}
}
}
func runConsumer(config *kafka.ConfigMap, topic string) {
c, err := kafka.NewConsumer(config)
if err != nil {
fatal(fmt.Sprintf("Failed to create consumer: %v", err))
}
_, verstr := kafka.LibraryVersion()
fmt.Fprintf(os.Stderr, "%% Created Consumer %v (%s)\n", c, verstr)
state.c = c
c.Subscribe(topic, nil)
send("startup_complete", nil)
state.run = true
mainLoop(c, 10*60)
tTermBegin := time.Now()
fmt.Fprintf(os.Stderr, "%% Consumer shutting down\n")
sendRecordsConsumed(true)
// Final commit (if auto commit is disabled)
doCommit(false, false)
c.Unsubscribe()
// Wait for rebalance, final offset commits, etc.
state.run = true
state.termOnRevoke = true
mainLoop(c, 10)
fmt.Fprintf(os.Stderr, "%% Closing consumer\n")
c.Close()
msg := make(map[string]interface{})
msg["_shutdown_duration"] = time.Since(tTermBegin).Seconds()
send("shutdown_complete", msg)
}
func main() {
sigs = make(chan os.Signal, 1)
signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
// Default config
conf := kafka.ConfigMap{"default.topic.config": kafka.ConfigMap{"auto.offset.reset": "earliest"}}
/* Required options */
group := kingpin.Flag("group-id", "Consumer group").Required().String()
topic := kingpin.Flag("topic", "Topic to consume").Required().String()
brokers := kingpin.Flag("broker-list", "Bootstrap broker(s)").Required().String()
sessionTimeout := kingpin.Flag("session-timeout", "Session timeout").Required().Int()
/* Optionals */
enableAutocommit := kingpin.Flag("enable-autocommit", "Enable auto-commit").Default("true").Bool()
maxMessages := kingpin.Flag("max-messages", "Max messages to consume").Default("10000000").Int()
javaAssignmentStrategy := kingpin.Flag("assignment-strategy", "Assignment strategy (Java class name)").String()
configFile := kingpin.Flag("consumer.config", "Config file").File()
debug := kingpin.Flag("debug", "Debug flags").String()
xconf := kingpin.Flag("--property", "CSV separated key=value librdkafka configuration properties").Short('X').String()
kingpin.Parse()
conf["bootstrap.servers"] = *brokers
conf["group.id"] = *group
conf["session.timeout.ms"] = *sessionTimeout
conf["enable.auto.commit"] = *enableAutocommit
if len(*debug) > 0 {
conf["debug"] = *debug
}
/* Convert Java assignment strategy to librdkafka one.
* "[java.class.path.]Strategy[Assignor]" -> "strategy" */
if javaAssignmentStrategy != nil && len(*javaAssignmentStrategy) > 0 {
s := strings.Split(*javaAssignmentStrategy, ".")
strategy := strings.ToLower(strings.TrimSuffix(s[len(s)-1], "Assignor"))
conf["partition.assignment.strategy"] = strategy
fmt.Fprintf(os.Stderr, "%% Mapped %s -> %s\n",
*javaAssignmentStrategy, conf["partition.assignment.strategy"])
}
if *configFile != nil {
fmt.Fprintf(os.Stderr, "%% Ignoring config file %v\n", *configFile)
}
conf["go.events.channel.enable"] = false
conf["go.application.rebalance.enable"] = true
if len(*xconf) > 0 {
for _, kv := range strings.Split(*xconf, ",") {
x := strings.Split(kv, "=")
if len(x) != 2 {
panic("-X expects a ,-separated list of confprop=val pairs")
}
conf[x[0]] = x[1]
}
}
fmt.Println("Config: ", conf)
state.autoCommit = *enableAutocommit
state.maxMessages = *maxMessages
runConsumer((*kafka.ConfigMap)(&conf), *topic)
}