Add support for gzip compression to amqp input and output

internal/content_coding.go

@@ -0,0 +1,122 @@
+package internal
+
+import (
+	"bytes"
+	"compress/gzip"
+	"errors"
+	"io"
+)
+
+// NewContentEncoder returns a ContentEncoder for the encoding type.
+func NewContentEncoder(encoding string) (ContentEncoder, error) {
+	switch encoding {
+	case "gzip":
+		return NewGzipEncoder()
+
+	case "identity", "":
+		return NewIdentityEncoder(), nil
+	default:
+		return nil, errors.New("invalid value for content_encoding")
+	}
+}
+
+// NewContentDecoder returns a ContentDecoder for the encoding type.
+func NewContentDecoder(encoding string) (ContentDecoder, error) {
+	switch encoding {
+	case "gzip":
+		return NewGzipDecoder()
+	case "identity", "":
+		return NewIdentityDecoder(), nil
+	default:
+		return nil, errors.New("invalid value for content_encoding")
+	}
+}
+
+// ContentEncoder applies a wrapper encoding to byte buffers.
+type ContentEncoder interface {
+	Encode([]byte) ([]byte, error)
+}
+
+// GzipEncoder compresses the buffer using gzip at the default level.
+type GzipEncoder struct {
+	writer *gzip.Writer
+	buf    *bytes.Buffer
+}
+
+func NewGzipEncoder() (*GzipEncoder, error) {
+	var buf bytes.Buffer
+	return &GzipEncoder{
+		writer: gzip.NewWriter(&buf),
+		buf:    &buf,
+	}, nil
+}
+
+func (e *GzipEncoder) Encode(data []byte) ([]byte, error) {
+	e.buf.Reset()
+	e.writer.Reset(e.buf)
+
+	_, err := e.writer.Write(data)
+	if err != nil {
+		return nil, err
+	}
+	err = e.writer.Close()
+	if err != nil {
+		return nil, err
+	}
+	return e.buf.Bytes(), nil
+}
+
+// IdentityEncoder is a null encoder that applies no transformation.
+type IdentityEncoder struct{}
+
+func NewIdentityEncoder() *IdentityEncoder {
+	return &IdentityEncoder{}
+}
+
+func (*IdentityEncoder) Encode(data []byte) ([]byte, error) {
+	return data, nil
+}
+
+// ContentDecoder removes a wrapper encoding from byte buffers.
+type ContentDecoder interface {
+	Decode([]byte) ([]byte, error)
+}
+
+// GzipDecoder decompresses buffers with gzip compression.
+type GzipDecoder struct {
+	reader *gzip.Reader
+	buf    *bytes.Buffer
+}
+
+func NewGzipDecoder() (*GzipDecoder, error) {
+	return &GzipDecoder{
+		reader: new(gzip.Reader),
+		buf:    new(bytes.Buffer),
+	}, nil
+}
+
+func (d *GzipDecoder) Decode(data []byte) ([]byte, error) {
+	d.reader.Reset(bytes.NewBuffer(data))
+	d.buf.Reset()
+
+	_, err := d.buf.ReadFrom(d.reader)
+	if err != nil && err != io.EOF {
+		return nil, err
+	}
+	err = d.reader.Close()
+	if err != nil {
+		return nil, err
+	}
+	return d.buf.Bytes(), nil
+}
+
+// IdentityDecoder is a null decoder that returns the input.
+type IdentityDecoder struct{}
+
+func NewIdentityDecoder() *IdentityDecoder {
+	return &IdentityDecoder{}
+}
+
+func (*IdentityDecoder) Decode(data []byte) ([]byte, error) {
+	return data, nil
+}

internal/content_coding_test.go

@@ -0,0 +1,58 @@
+package internal
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGzipEncodeDecode(t *testing.T) {
+	enc, err := NewGzipEncoder()
+	require.NoError(t, err)
+	dec, err := NewGzipDecoder()
+	require.NoError(t, err)
+
+	payload, err := enc.Encode([]byte("howdy"))
+	require.NoError(t, err)
+
+	actual, err := dec.Decode(payload)
+	require.NoError(t, err)
+
+	require.Equal(t, "howdy", string(actual))
+}
+
+func TestGzipReuse(t *testing.T) {
+	enc, err := NewGzipEncoder()
+	require.NoError(t, err)
+	dec, err := NewGzipDecoder()
+	require.NoError(t, err)
+
+	payload, err := enc.Encode([]byte("howdy"))
+	require.NoError(t, err)
+
+	actual, err := dec.Decode(payload)
+	require.NoError(t, err)
+
+	require.Equal(t, "howdy", string(actual))
+
+	payload, err = enc.Encode([]byte("doody"))
+	require.NoError(t, err)
+
+	actual, err = dec.Decode(payload)
+	require.NoError(t, err)
+
+	require.Equal(t, "doody", string(actual))
+}
+
+func TestIdentityEncodeDecode(t *testing.T) {
+	enc := NewIdentityEncoder()
+	dec := NewIdentityDecoder()
+
+	payload, err := enc.Encode([]byte("howdy"))
+	require.NoError(t, err)
+
+	actual, err := dec.Decode(payload)
+	require.NoError(t, err)
+
+	require.Equal(t, "howdy", string(actual))
+}

plugins/inputs/amqp_consumer/README.md

@@ -77,6 +77,10 @@ The following defaults are known to work with RabbitMQ:
   ## Use TLS but skip chain & host verification
   # insecure_skip_verify = false
 
+  ## Content encoding for message payloads, can be set to "gzip" to or
+  ## "identity" to apply no encoding.
+  # content_encoding = "identity"
+
   ## Data format to consume.
   ## Each data format has its own unique set of configuration options, read
   ## more about them here:

plugins/inputs/amqp_consumer/amqp_consumer.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/internal/tls"
 	"github.com/influxdata/telegraf/plugins/inputs"
 	"github.com/influxdata/telegraf/plugins/parsers"
@@ -52,12 +53,15 @@ type AMQPConsumer struct {
 	AuthMethod string
 	tls.ClientConfig
 
+	ContentEncoding string `toml:"content_encoding"`
+
 	deliveries map[telegraf.TrackingID]amqp.Delivery
 
-	parser parsers.Parser
-	conn   *amqp.Connection
-	wg     *sync.WaitGroup
-	cancel context.CancelFunc
+	parser  parsers.Parser
+	conn    *amqp.Connection
+	wg      *sync.WaitGroup
+	cancel  context.CancelFunc
+	decoder internal.ContentDecoder
 }
 
 type externalAuth struct{}
@@ -147,6 +151,10 @@ func (a *AMQPConsumer) SampleConfig() string {
   ## Use TLS but skip chain & host verification
   # insecure_skip_verify = false
 
+  ## Content encoding for message payloads, can be set to "gzip" to or
+  ## "identity" to apply no encoding.
+  # content_encoding = "identity"
+
   ## Data format to consume.
   ## Each data format has its own unique set of configuration options, read
   ## more about them here:
@@ -201,6 +209,11 @@ func (a *AMQPConsumer) Start(acc telegraf.Accumulator) error {
 		return err
 	}
 
+	a.decoder, err = internal.NewContentDecoder(a.ContentEncoding)
+	if err != nil {
+		return err
+	}
+
 	msgs, err := a.connect(amqpConf)
 	if err != nil {
 		return err
@@ -428,8 +441,7 @@ func (a *AMQPConsumer) process(ctx context.Context, msgs <-chan amqp.Delivery, a
 }
 
 func (a *AMQPConsumer) onMessage(acc telegraf.TrackingAccumulator, d amqp.Delivery) error {
-	metrics, err := a.parser.Parse(d.Body)
-	if err != nil {
+	onError := func() {
 		// Discard the message from the queue; will never be able to process
 		// this message.
 		rejErr := d.Ack(false)
@@ -438,6 +450,17 @@ func (a *AMQPConsumer) onMessage(acc telegraf.TrackingAccumulator, d amqp.Delive
 				d.DeliveryTag, rejErr)
 			a.conn.Close()
 		}
+	}
+
+	body, err := a.decoder.Decode(d.Body)
+	if err != nil {
+		onError()
+		return err
+	}
+
+	metrics, err := a.parser.Parse(body)
+	if err != nil {
+		onError()
 		return err
 	}
 

plugins/outputs/amqp/README.md

@@ -92,6 +92,14 @@ For an introduction to AMQP see:
   ## Recommended to set to true.
   # use_batch_format = false
 
+  ## Content encoding for message payloads, can be set to "gzip" to or
+  ## "identity" to apply no encoding.
+  ##
+  ## Please note that when use_batch_format = false each amqp message contains only
+  ## a single metric, it is recommended to use compression with batch format
+  ## for best results.
+  # content_encoding = "identity"
+
   ## Data format to output.
   ## Each data format has its own unique set of configuration options, read
   ## more about them here:

plugins/outputs/amqp/amqp.go

@@ -12,7 +12,6 @@ import (
 	"github.com/influxdata/telegraf/internal/tls"
 	"github.com/influxdata/telegraf/plugins/outputs"
 	"github.com/influxdata/telegraf/plugins/serializers"
-
 	"github.com/streadway/amqp"
 )
 
@@ -55,13 +54,15 @@ type AMQP struct {
 	Headers            map[string]string `toml:"headers"`
 	Timeout            internal.Duration `toml:"timeout"`
 	UseBatchFormat     bool              `toml:"use_batch_format"`
+	ContentEncoding    string            `toml:"content_encoding"`
 	tls.ClientConfig
 
 	serializer   serializers.Serializer
 	connect      func(*ClientConfig) (Client, error)
 	client       Client
 	config       *ClientConfig
 	sentMessages int
+	encoder      internal.ContentEncoder
 }
 
 type Client interface {
@@ -150,6 +151,14 @@ var sampleConfig = `
   ## Recommended to set to true.
   # use_batch_format = false
 
+  ## Content encoding for message payloads, can be set to "gzip" to or
+  ## "identity" to apply no encoding.
+  ##
+  ## Please note that when use_batch_format = false each amqp message contains only
+  ## a single metric, it is recommended to use compression with batch format
+  ## for best results.
+  # content_encoding = "identity"
+
   ## Data format to output.
   ## Each data format has its own unique set of configuration options, read
   ## more about them here:
@@ -178,11 +187,16 @@ func (q *AMQP) Connect() error {
 		q.config = config
 	}
 
-	client, err := q.connect(q.config)
+	var err error
+	q.encoder, err = internal.NewContentEncoder(q.ContentEncoding)
+	if err != nil {
+		return err
+	}
+
+	q.client, err = q.connect(q.config)
 	if err != nil {
 		return err
 	}
-	q.client = client
 
 	return nil
 }
@@ -228,6 +242,11 @@ func (q *AMQP) Write(metrics []telegraf.Metric) error {
 			return err
 		}
 
+		body, err = q.encoder.Encode(body)
+		if err != nil {
+			return err
+		}
+
 		err = q.publish(key, body)
 		if err != nil {
 			// If this is the first attempt to publish and the connection is
@@ -299,6 +318,7 @@ func (q *AMQP) makeClientConfig() (*ClientConfig, error) {
 		exchange:        q.Exchange,
 		exchangeType:    q.ExchangeType,
 		exchangePassive: q.ExchangePassive,
+		encoding:        q.ContentEncoding,
 		timeout:         q.Timeout.Duration,
 	}
 

plugins/outputs/amqp/client.go

@@ -19,6 +19,7 @@ type ClientConfig struct {
 	exchangePassive   bool
 	exchangeDurable   bool
 	exchangeArguments amqp.Table
+	encoding          string
 	headers           amqp.Table
 	deliveryMode      uint8
 	tlsConfig         *tls.Config
@@ -114,10 +115,11 @@ func (c *client) Publish(key string, body []byte) error {
 		false,             // mandatory
 		false,             // immediate
 		amqp.Publishing{
-			Headers:      c.config.headers,
-			ContentType:  "text/plain",
-			Body:         body,
-			DeliveryMode: c.config.deliveryMode,
+			Headers:         c.config.headers,
+			ContentType:     "text/plain",
+			ContentEncoding: c.config.encoding,
+			Body:            body,
+			DeliveryMode:    c.config.deliveryMode,
 		})
 }