Add awslogs driver for Amazon CloudWatch Logs

Signed-off-by: Samuel Karp <[email protected]>

Author: samuelkarp

contrib/completion/bash/docker

@@ -279,6 +279,7 @@ __docker_log_driver_options() {
 	local gelf_options="gelf-address gelf-tag"
 	local json_file_options="max-file max-size"
 	local syslog_options="syslog-address syslog-facility syslog-tag"
+	local awslogs_options="awslogs-region awslogs-group awslogs-stream"
 
 	case $(__docker_value_of_option --log-driver) in
 		'')
@@ -296,6 +297,9 @@ __docker_log_driver_options() {
 		syslog)
 			COMPREPLY=( $( compgen -W "$syslog_options" -S = -- "$cur" ) )
 			;;
+		awslogs)
+			COMPREPLY=( $( compgen -W "$awslogs_options" -S = -- "$cur" ) )
+			;;
 		*)
 			return
 			;;

contrib/completion/zsh/_docker

@@ -238,7 +238,7 @@ __docker_subcommand() {
         "($help)--ipc=-[IPC namespace to use]:IPC namespace: "
         "($help)*--link=-[Add link to another container]:link:->link"
         "($help)*"{-l,--label=-}"[Set meta data on a container]:label: "
-        "($help)--log-driver=-[Default driver for container logs]:Logging driver:(json-file syslog journald gelf fluentd none)"
+        "($help)--log-driver=-[Default driver for container logs]:Logging driver:(json-file syslog journald gelf fluentd awslogs none)"
         "($help)*--log-opt=-[Log driver specific options]:log driver options: "
         "($help)*--lxc-conf=-[Add custom lxc options]:lxc options: "
         "($help)--mac-address=-[Container MAC address]:MAC address: "
@@ -617,7 +617,7 @@ _docker() {
         "($help)--ipv6[Enable IPv6 networking]" \
         "($help -l --log-level)"{-l,--log-level=-}"[Set the logging level]:level:(debug info warn error fatal)" \
         "($help)*--label=-[Set key=value labels to the daemon]:label: " \
-        "($help)--log-driver=-[Default driver for container logs]:Logging driver:(json-file syslog journald gelf fluentd none)" \
+        "($help)--log-driver=-[Default driver for container logs]:Logging driver:(json-file syslog journald gelf fluentd awslogs none)" \
         "($help)*--log-opt=-[Log driver specific options]:log driver options: " \
         "($help)--mtu=-[Set the containers network MTU]:mtu:(0 576 1420 1500 9000)" \
         "($help -p --pidfile)"{-p,--pidfile=-}"[Path to use for daemon PID file]:PID file:_files" \

daemon/logdrivers_linux.go

@@ -3,6 +3,7 @@ package daemon
 import (
 	// Importing packages here only to make sure their init gets called and
 	// therefore they register themselves to the logdriver factory.
+	_ "github.com/docker/docker/daemon/logger/awslogs"
 	_ "github.com/docker/docker/daemon/logger/fluentd"
 	_ "github.com/docker/docker/daemon/logger/gelf"
 	_ "github.com/docker/docker/daemon/logger/journald"

daemon/logdrivers_windows.go

@@ -3,5 +3,6 @@ package daemon
 import (
 	// Importing packages here only to make sure their init gets called and
 	// therefore they register themselves to the logdriver factory.
+	_ "github.com/docker/docker/daemon/logger/awslogs"
 	_ "github.com/docker/docker/daemon/logger/jsonfilelog"
 )

daemon/logger/awslogs/cloudwatchlogs.go

@@ -0,0 +1,326 @@
+// Package awslogs provides the logdriver for forwarding container logs to Amazon CloudWatch Logs
+package awslogs
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/awserr"
+	"github.com/aws/aws-sdk-go/service/cloudwatchlogs"
+	"github.com/docker/docker/daemon/logger"
+	"github.com/docker/docker/vendor/src/github.com/Sirupsen/logrus"
+)
+
+const (
+	name                  = "awslogs"
+	regionKey             = "awslogs-region"
+	regionEnvKey          = "AWS_REGION"
+	logGroupKey           = "awslogs-group"
+	logStreamKey          = "awslogs-stream"
+	batchPublishFrequency = 5 * time.Second
+
+	// See: http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutLogEvents.html
+	perEventBytes          = 26
+	maximumBytesPerPut     = 1048576
+	maximumLogEventsPerPut = 10000
+
+	// See: http://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/cloudwatch_limits.html
+	maximumBytesPerEvent = 262144 - perEventBytes
+
+	resourceAlreadyExistsCode = "ResourceAlreadyExistsException"
+	dataAlreadyAcceptedCode   = "DataAlreadyAcceptedException"
+	invalidSequenceTokenCode  = "InvalidSequenceTokenException"
+)
+
+type logStream struct {
+	logStreamName string
+	logGroupName  string
+	client        api
+	messages      chan *logger.Message
+	lock          sync.RWMutex
+	closed        bool
+	sequenceToken *string
+}
+
+type api interface {
+	CreateLogStream(*cloudwatchlogs.CreateLogStreamInput) (*cloudwatchlogs.CreateLogStreamOutput, error)
+	PutLogEvents(*cloudwatchlogs.PutLogEventsInput) (*cloudwatchlogs.PutLogEventsOutput, error)
+}
+
+type byTimestamp []*cloudwatchlogs.InputLogEvent
+
+// init registers the awslogs driver and sets the default region, if provided
+func init() {
+	if os.Getenv(regionEnvKey) != "" {
+		aws.DefaultConfig.Region = aws.String(os.Getenv(regionEnvKey))
+	}
+	if err := logger.RegisterLogDriver(name, New); err != nil {
+		logrus.Fatal(err)
+	}
+	if err := logger.RegisterLogOptValidator(name, ValidateLogOpt); err != nil {
+		logrus.Fatal(err)
+	}
+}
+
+// New creates an awslogs logger using the configuration passed in on the
+// context.  Supported context configuration variables are awslogs-region,
+// awslogs-group, and awslogs-stream.  When available, configuration is
+// also taken from environment variables AWS_REGION, AWS_ACCESS_KEY_ID,
+// AWS_SECRET_ACCESS_KEY, the shared credentials file (~/.aws/credentials), and
+// the EC2 Instance Metadata Service.
+func New(ctx logger.Context) (logger.Logger, error) {
+	logGroupName := ctx.Config[logGroupKey]
+	logStreamName := ctx.ContainerID
+	if ctx.Config[logStreamKey] != "" {
+		logStreamName = ctx.Config[logStreamKey]
+	}
+	config := aws.DefaultConfig
+	if ctx.Config[regionKey] != "" {
+		config = aws.DefaultConfig.Merge(&aws.Config{
+			Region: aws.String(ctx.Config[regionKey]),
+		})
+	}
+	containerStream := &logStream{
+		logStreamName: logStreamName,
+		logGroupName:  logGroupName,
+		client:        cloudwatchlogs.New(config),
+		messages:      make(chan *logger.Message, 4096),
+	}
+	err := containerStream.create()
+	if err != nil {
+		return nil, err
+	}
+	go containerStream.collectBatch()
+
+	return containerStream, nil
+}
+
+// Name returns the name of the awslogs logging driver
+func (l *logStream) Name() string {
+	return name
+}
+
+// Log submits messages for logging by an instance of the awslogs logging driver
+func (l *logStream) Log(msg *logger.Message) error {
+	l.lock.RLock()
+	defer l.lock.RUnlock()
+	if !l.closed {
+		l.messages <- msg
+	}
+	return nil
+}
+
+// Close closes the instance of the awslogs logging driver
+func (l *logStream) Close() error {
+	l.lock.Lock()
+	defer l.lock.Unlock()
+	if !l.closed {
+		close(l.messages)
+	}
+	l.closed = true
+	return nil
+}
+
+// create creates a log stream for the instance of the awslogs logging driver
+func (l *logStream) create() error {
+	input := &cloudwatchlogs.CreateLogStreamInput{
+		LogGroupName:  aws.String(l.logGroupName),
+		LogStreamName: aws.String(l.logStreamName),
+	}
+
+	_, err := l.client.CreateLogStream(input)
+
+	if err != nil {
+		if awsErr, ok := err.(awserr.Error); ok {
+			fields := logrus.Fields{
+				"errorCode":     awsErr.Code(),
+				"message":       awsErr.Message(),
+				"origError":     awsErr.OrigErr(),
+				"logGroupName":  l.logGroupName,
+				"logStreamName": l.logStreamName,
+			}
+			if awsErr.Code() == resourceAlreadyExistsCode {
+				// Allow creation to succeed
+				logrus.WithFields(fields).Info("Log stream already exists")
+				return nil
+			}
+			logrus.WithFields(fields).Error("Failed to create log stream")
+		}
+	}
+	return err
+}
+
+// newTicker is used for time-based batching.  newTicker is a variable such
+// that the implementation can be swapped out for unit tests.
+var newTicker = func(freq time.Duration) *time.Ticker {
+	return time.NewTicker(freq)
+}
+
+// collectBatch executes as a goroutine to perform batching of log events for
+// submission to the log stream.  Batching is performed on time- and size-
+// bases.  Time-based batching occurs at a 5 second interval (defined in the
+// batchPublishFrequency const).  Size-based batching is performed on the
+// maximum number of events per batch (defined in maximumLogEventsPerPut) and
+// the maximum number of total bytes in a batch (defined in
+// maximumBytesPerPut).  Log messages are split by the maximum bytes per event
+// (defined in maximumBytesPerEvent).  There is a fixed per-event byte overhead
+// (defined in perEventBytes) which is accounted for in split- and batch-
+// calculations.
+func (l *logStream) collectBatch() {
+	timer := newTicker(batchPublishFrequency)
+	var events []*cloudwatchlogs.InputLogEvent
+	bytes := 0
+	for {
+		select {
+		case <-timer.C:
+			l.publishBatch(events)
+			events = events[:0]
+			bytes = 0
+		case msg, more := <-l.messages:
+			if !more {
+				l.publishBatch(events)
+				return
+			}
+			unprocessedLine := msg.Line
+			for len(unprocessedLine) > 0 {
+				// Split line length so it does not exceed the maximum
+				lineBytes := len(unprocessedLine)
+				if lineBytes > maximumBytesPerEvent {
+					lineBytes = maximumBytesPerEvent
+				}
+				line := unprocessedLine[:lineBytes]
+				unprocessedLine = unprocessedLine[lineBytes:]
+				if (len(events) >= maximumLogEventsPerPut) || (bytes+lineBytes+perEventBytes > maximumBytesPerPut) {
+					// Publish an existing batch if it's already over the maximum number of events or if adding this
+					// event would push it over the maximum number of total bytes.
+					l.publishBatch(events)
+					events = events[:0]
+					bytes = 0
+				}
+				events = append(events, &cloudwatchlogs.InputLogEvent{
+					Message:   aws.String(string(line)),
+					Timestamp: aws.Int64(msg.Timestamp.UnixNano() / int64(time.Millisecond)),
+				})
+				bytes += (lineBytes + perEventBytes)
+			}
+		}
+	}
+}
+
+// publishBatch calls PutLogEvents for a given set of InputLogEvents,
+// accounting for sequencing requirements (each request must reference the
+// sequence token returned by the previous request).
+func (l *logStream) publishBatch(events []*cloudwatchlogs.InputLogEvent) {
+	if len(events) == 0 {
+		return
+	}
+
+	sort.Sort(byTimestamp(events))
+
+	nextSequenceToken, err := l.putLogEvents(events, l.sequenceToken)
+
+	if err != nil {
+		if awsErr, ok := err.(awserr.Error); ok {
+			if awsErr.Code() == dataAlreadyAcceptedCode {
+				// already submitted, just grab the correct sequence token
+				parts := strings.Split(awsErr.Message(), " ")
+				nextSequenceToken = &parts[len(parts)-1]
+				logrus.WithFields(logrus.Fields{
+					"errorCode":     awsErr.Code(),
+					"message":       awsErr.Message(),
+					"logGroupName":  l.logGroupName,
+					"logStreamName": l.logStreamName,
+				}).Info("Data already accepted, ignoring error")
+				err = nil
+			} else if awsErr.Code() == invalidSequenceTokenCode {
+				// sequence code is bad, grab the correct one and retry
+				parts := strings.Split(awsErr.Message(), " ")
+				token := parts[len(parts)-1]
+				nextSequenceToken, err = l.putLogEvents(events, &token)
+			}
+		}
+	}
+	if err != nil {
+		logrus.Error(err)
+	} else {
+		l.sequenceToken = nextSequenceToken
+	}
+}
+
+// putLogEvents wraps the PutLogEvents API
+func (l *logStream) putLogEvents(events []*cloudwatchlogs.InputLogEvent, sequenceToken *string) (*string, error) {
+	input := &cloudwatchlogs.PutLogEventsInput{
+		LogEvents:     events,
+		SequenceToken: sequenceToken,
+		LogGroupName:  aws.String(l.logGroupName),
+		LogStreamName: aws.String(l.logStreamName),
+	}
+	resp, err := l.client.PutLogEvents(input)
+	if err != nil {
+		if awsErr, ok := err.(awserr.Error); ok {
+			logrus.WithFields(logrus.Fields{
+				"errorCode":     awsErr.Code(),
+				"message":       awsErr.Message(),
+				"origError":     awsErr.OrigErr(),
+				"logGroupName":  l.logGroupName,
+				"logStreamName": l.logStreamName,
+			}).Error("Failed to put log events")
+		}
+		return nil, err
+	}
+	return resp.NextSequenceToken, nil
+}
+
+// ValidateLogOpt looks for awslogs-specific log options awslogs-region,
+// awslogs-group, and awslogs-stream
+func ValidateLogOpt(cfg map[string]string) error {
+	for key := range cfg {
+		switch key {
+		case logGroupKey:
+		case logStreamKey:
+		case regionKey:
+		default:
+			return fmt.Errorf("unknown log opt '%s' for %s log driver", key, name)
+		}
+	}
+	if cfg[logGroupKey] == "" {
+		return fmt.Errorf("must specify a value for log opt '%s'", logGroupKey)
+	}
+	if cfg[regionKey] == "" && os.Getenv(regionEnvKey) == "" {
+		return fmt.Errorf(
+			"must specify a value for environment variable '%s' or log opt '%s'",
+			regionEnvKey,
+			regionKey)
+	}
+	return nil
+}
+
+// Len returns the length of a byTimestamp slice.  Len is required by the
+// sort.Interface interface.
+func (slice byTimestamp) Len() int {
+	return len(slice)
+}
+
+// Less compares two values in a byTimestamp slice by Timestamp.  Less is
+// required by the sort.Interface interface.
+func (slice byTimestamp) Less(i, j int) bool {
+	iTimestamp, jTimestamp := int64(0), int64(0)
+	if slice != nil && slice[i].Timestamp != nil {
+		iTimestamp = *slice[i].Timestamp
+	}
+	if slice != nil && slice[j].Timestamp != nil {
+		jTimestamp = *slice[j].Timestamp
+	}
+	return iTimestamp < jTimestamp
+}
+
+// Swap swaps two values in a byTimestamp slice with each other.  Swap is
+// required by the sort.Interface interface.
+func (slice byTimestamp) Swap(i, j int) {
+	slice[i], slice[j] = slice[j], slice[i]
+}