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awsCloudwatchlogs.go
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awsCloudwatchlogs.go
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// 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 producer
import (
"sort"
"sync"
"time"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/awserr"
"github.com/aws/aws-sdk-go/aws/endpoints"
"github.com/aws/aws-sdk-go/service/cloudwatchlogs"
"github.com/trivago/gollum/core"
"github.com/trivago/gollum/core/components"
)
// AWS CloudWatch specific constants.
// Also see http://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/cloudwatch_limits_cwl.html
const (
// Maximum number of log events in a batch.
maxBatchEvents = 10000
// Maximum batch size in bytes.
maxBatchSize = 1048576
// Maximum event size in bytes.
//maxEventSize = 262144
// A batch of log events in a single PutLogEvents request cannot span more than 24 hours.
maxBatchTimeSpan = 24 * time.Hour
// How many bytes to append to each log event.
eventSizeOverhead = 26
// DescribeLogStreams transactions/second.
//describeLogstreamsDelay = 200 * time.Millisecond
// PutLogEvents 5 requests/second/log stream.
//putLogEventsDelay = 200 * time.Millisecond
)
// AwsCloudwatchLogs producer
//
// The AwsCloudwatchLogs producer plugin sends messages to
// AWS Cloudwatch Logs service. Credentials are obtained by gollum automaticly.
//
// Patameters
//
// - LogStream: Stream name in cloudwatch logs.
//
// - LogGroup: Group name in cloudwatch logs.
//
// - Region: Amazon region into which stream logs to. Defaults to "eu-west-1".
//
// Examples
//
// This configuration sends messages to stream stream_name and group group_name with shared credentials.
//
// CwLogs:
// Type: AwsCloudwatchLogs:
// LogStream: stream_name
// LogGroup: group_name
// Credential:
// Type: shared
type AwsCloudwatchLogs struct {
AwsMultiClient components.AwsMultiClient `gollumdoc:"embed_type"`
core.BatchedProducer `gollumdoc:"embed_type"`
stream string `config:"LogStream" default:""`
group string `config:"LogGroup" default:""`
token *string
service *cloudwatchlogs.CloudWatchLogs
}
func init() {
core.TypeRegistry.Register(AwsCloudwatchLogs{})
}
// Configure initializes this producer with values from a plugin config.
func (prod *AwsCloudwatchLogs) Configure(conf core.PluginConfigReader) {
if prod.stream == "" {
prod.Logger.Error("LogStream can not be empty")
}
if prod.group == "" {
prod.Logger.Error("LogGroup can not be empty")
}
if conf.GetInt("Batch/MaxCount", maxBatchEvents) > maxBatchEvents {
conf.Errors.Pushf("Batch/MaxCount must be below %d", maxBatchEvents)
}
}
func (m byTimestamp) Len() int {
return len(m)
}
func (m byTimestamp) Swap(i, j int) {
m[i], m[j] = m[j], m[i]
}
func (m byTimestamp) Less(i, j int) bool {
return m[i].GetCreationTime().Unix() < m[j].GetCreationTime().Unix()
}
type byTimestamp []*core.Message
// Return lowest index based on all check functions
// This function assumes that messages are sorted by timestamp in ascending order
func (prod *AwsCloudwatchLogs) numEvents(messages []*core.Message, checkFn ...indexNumFn) int {
index := maxBatchEvents
for _, fn := range checkFn {
result := fn(messages)
if result < index {
index = result
}
}
return index
}
type indexNumFn func(messages []*core.Message) int
// Return lowest index based on message size
func (prod *AwsCloudwatchLogs) sizeIndex(messages []*core.Message) int {
size, index := 0, 0
for i, message := range messages {
size += len(message.String()) + eventSizeOverhead
if size > maxBatchSize {
break
}
index = i + 1
}
return index
}
// Return lowest index based on timespan
// This function assumes that messages are sorted by timestamp in ascending order
func (prod *AwsCloudwatchLogs) timeIndex(messages []*core.Message) (index int) {
if len(messages) == 0 {
return 0
}
firstTimestamp := messages[0].GetCreationTime().Unix()
for i, message := range messages {
if (message.GetCreationTime().Unix() - firstTimestamp) > int64(maxBatchTimeSpan) {
break
}
index = i + 1
}
return index
}
func (prod *AwsCloudwatchLogs) processBatch(messages []*core.Message) []*core.Message {
sort.Sort(byTimestamp(messages))
return messages[:prod.numEvents(messages, prod.sizeIndex, prod.timeIndex)]
}
// Put log events and update sequence token.
// Possible errors http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutLogEvents.html
func (prod *AwsCloudwatchLogs) upload(messages []*core.Message) {
messages = prod.processBatch(messages)
if len(messages) == 0 {
return
}
logevents := make([]*cloudwatchlogs.InputLogEvent, 0, len(messages))
for _, msg := range messages {
logevents = append(logevents, &cloudwatchlogs.InputLogEvent{
Message: aws.String(msg.String()),
Timestamp: aws.Int64(msg.GetCreationTime().Unix() * 1000),
})
}
params := &cloudwatchlogs.PutLogEventsInput{
LogEvents: logevents,
LogGroupName: aws.String(prod.group),
LogStreamName: aws.String(prod.stream),
SequenceToken: prod.token,
}
prod.handleResult(prod.service.PutLogEvents(params))
}
// When rejectedLogEventsInfo is not empty, app can not
// do anything reasonable with rejected logs. Ignore it.
func (prod *AwsCloudwatchLogs) handleResult(resp *cloudwatchlogs.PutLogEventsOutput, result error) {
switch err := result.(type) {
case awserr.Error:
switch err.Code() {
case "InvalidSequenceTokenException":
prod.Logger.Debugf("invalid sequence token, updating")
prod.setToken()
case "ResourceNotFoundException":
prod.Logger.Debugf("missing group/stream, creating")
prod.create()
prod.token = nil
default:
prod.Logger.Errorf("error while sending batch. code: %s message: %q", err.Code(), err.Message())
}
case nil:
prod.token = resp.NextSequenceToken
default:
prod.Logger.Errorf("error while sending batch: %q", err)
}
}
func (prod *AwsCloudwatchLogs) sendBatch() core.AssemblyFunc {
return prod.upload
}
// Produce starts the producer
func (prod *AwsCloudwatchLogs) Produce(workers *sync.WaitGroup) {
prod.initService()
if err := prod.create(); err != nil {
prod.Logger.Errorf("could not create group:%q stream:%q error was: %q", prod.group, prod.stream, err)
} else {
prod.setToken()
}
prod.BatchMessageLoop(workers, prod.sendBatch)
}
func (prod *AwsCloudwatchLogs) initService() {
sess, err := prod.AwsMultiClient.NewSessionWithOptions()
if err != nil {
prod.Logger.WithError(err).Error("Can't get proper aws config")
}
awsConfig := prod.AwsMultiClient.GetConfig()
// Fill in nedpoint URL if not provided
if awsConfig.Endpoint == nil || *awsConfig.Endpoint == "" {
resolver := endpoints.DefaultResolver()
endpoint, err := resolver.EndpointFor(endpoints.LogsServiceID, *awsConfig.Region)
if err != nil {
prod.Logger.WithError(err).Error("Can't resolve cloudwatch logs endpoint URL")
}
awsConfig.WithEndpoint(endpoint.URL)
}
prod.service = cloudwatchlogs.New(sess, awsConfig)
}
// For newly created log streams, token is an empty string.
func (prod *AwsCloudwatchLogs) setToken() error {
params := &cloudwatchlogs.DescribeLogStreamsInput{
LogGroupName: &prod.group,
LogStreamNamePrefix: &prod.stream,
}
return prod.service.DescribeLogStreamsPages(params,
func(page *cloudwatchlogs.DescribeLogStreamsOutput, lastPage bool) bool {
return !findToken(prod, page)
})
}
func findToken(prod *AwsCloudwatchLogs, page *cloudwatchlogs.DescribeLogStreamsOutput) bool {
for _, row := range page.LogStreams {
if prod.stream == *row.LogStreamName {
prod.token = row.UploadSequenceToken
return true
}
}
return false
}
// Create log group and stream. If an error is returned, PutLogEvents cannot succeed.
func (prod *AwsCloudwatchLogs) create() error {
if err := prod.createGroup(); err != nil {
return err
}
return prod.createStream()
}
// http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_CreateLogGroup.html
func (prod *AwsCloudwatchLogs) createGroup() error {
params := &cloudwatchlogs.CreateLogGroupInput{
LogGroupName: &prod.group,
}
_, err := prod.service.CreateLogGroup(params)
if awsErr, ok := err.(awserr.Error); ok {
if awsErr.Code() == "ResourceAlreadyExistsException" {
return nil
}
}
return err
}
// http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_CreateLogStream.html
func (prod *AwsCloudwatchLogs) createStream() error {
params := &cloudwatchlogs.CreateLogStreamInput{
LogGroupName: &prod.group,
LogStreamName: &prod.stream,
}
_, err := prod.service.CreateLogStream(params)
if awsErr, ok := err.(awserr.Error); ok {
if awsErr.Code() == "ResourceAlreadyExistsException" {
return nil
}
}
return err
}