Merged in revid/loadsender (pull request #28)

revid: use loadSender for clip sending

cmd/revid-cli/main.go

@@ -95,7 +95,7 @@ const (
 
 // Globals
 var (
-	revidInst revid.Revid
+	revidInst *revid.Revid
 	config    revid.Config
 )
 
@@ -341,7 +341,7 @@ func startRevid() {
 func createRevidInstance() {
 	// Try to create the revid instance with the given config
 	var err error
-	for revidInst, err = revid.NewRevid(config); err != nil; {
+	for revidInst, err = revid.New(config); err != nil; {
 		// If the config does have a logger, use it to output error, otherwise
 		// just output to std output
 		if config.Logger != nil {

revid/config.go

@@ -104,46 +104,46 @@ const (
 
 // Validate checks for any errors in the config fields and defaults settings
 // if particular parameters have not been defined.
-func (config *Config) Validate(r *revid) error {
+func (c *Config) Validate(r *Revid) error {
-	switch config.Verbosity {
+	switch c.Verbosity {
 	case Yes:
 	case No:
 	case NothingDefined:
-		config.Verbosity = Yes
+		c.Verbosity = Yes
 		r.Log(Warning, "No verbosity mode defined, defaulting to no Verbosity!")
 	default:
 		return errors.New("Bad Verbosity defined in config!")
 	}
 
-	switch config.QuantizationMode {
+	switch c.QuantizationMode {
 	case QuantizationOn:
 	case QuantizationOff:
 	case NothingDefined:
 		r.Log(Warning, "No quantization mode defined, defaulting to QuantizationOff!")
-		config.QuantizationMode = QuantizationOff
+		c.QuantizationMode = QuantizationOff
 	default:
 		return errors.New("Bad QuantizationMode defined in config!")
 	}
 
-	switch config.Input {
+	switch c.Input {
 	case Rtp:
 	case Raspivid:
 	case File:
 	case NothingDefined:
 		r.Log(Warning, "No input type defined, defaulting to raspivid!")
-		config.Input = defaultInput
+		c.Input = defaultInput
 	default:
 		return errors.New("Bad input type defined in config!")
 	}
 
-	switch config.InputCodec {
+	switch c.InputCodec {
 	case H264:
-		if config.Bitrate != "" && config.Quantization != "" {
+		if c.Bitrate != "" && c.Quantization != "" {
-			bitrate, err := strconv.Atoi(config.Bitrate)
+			bitrate, err := strconv.Atoi(c.Bitrate)
 			if err != nil {
 				return errors.New("Something is wrong with bitrate in conig!")
 			}
-			quantization, err := strconv.Atoi(config.Quantization)
+			quantization, err := strconv.Atoi(c.Quantization)
 			if err != nil {
 				return errors.New("Something is wrong with quantization in config!")
 			}
@@ -152,141 +152,141 @@ func (config *Config) Validate(r *revid) error {
 			}
 		}
 	case Mjpeg:
-		if config.Quantization != "" {
+		if c.Quantization != "" {
-			quantization, err := strconv.Atoi(config.Quantization)
+			quantization, err := strconv.Atoi(c.Quantization)
 			if err != nil {
 				return errors.New("Something is wrong with quantization in config!")
 			}
-			if quantization > 0 || config.Bitrate == "" {
+			if quantization > 0 || c.Bitrate == "" {
 				return errors.New("Bad bitrate or quantization for mjpeg input!")
 			}
 		}
 	case NothingDefined:
 		r.Log(Warning, "No input codec defined, defaulting to h264!")
-		config.InputCodec = H264
+		c.InputCodec = H264
 		r.Log(Warning, "Defaulting bitrate to 0 and quantization to 35!")
-		config.Quantization = defaultQuantization
+		c.Quantization = defaultQuantization
 	default:
 		return errors.New("Bad input codec defined in config!")
 	}
 
-	switch config.Output {
+	switch c.Output {
 	case Http:
 	case File:
 	case NativeRtmp, FfmpegRtmp:
-		if config.RtmpUrl == "" {
+		if c.RtmpUrl == "" {
 			r.Log(Info, "No RTMP URL: falling back to HTTP")
-			config.Output = Http
+			c.Output = Http
 			break
 		}
 		r.Log(Info, "Defaulting frames per clip to 1 for rtmp output!")
-		config.FramesPerClip = "1"
+		c.FramesPerClip = "1"
 	case NothingDefined:
 		r.Log(Warning, "No output defined, defaulting to httpOut!")
-		config.Output = defaultOutput
+		c.Output = defaultOutput
 	default:
 		return errors.New("Bad output type defined in config!")
 	}
 
-	switch config.Packetization {
+	switch c.Packetization {
 	case None:
 	case Mpegts:
 	case Flv:
 	case NothingDefined:
 		r.Log(Warning, "No packetization option defined, defaulting to none!")
-		config.Packetization = Flv
+		c.Packetization = Flv
 	default:
 		return errors.New("Bad packetization option defined in config!")
 	}
 
-	switch config.HorizontalFlip {
+	switch c.HorizontalFlip {
 	case Yes:
 	case No:
 	case NothingDefined:
 		r.Log(Warning, "No horizontal flip option defined, defaulting to not flipped!")
-		config.HorizontalFlip = defaultHorizontalFlip
+		c.HorizontalFlip = defaultHorizontalFlip
 	default:
 		return errors.New("Bad horizontal flip option defined in config!")
 	}
 
-	switch config.VerticalFlip {
+	switch c.VerticalFlip {
 	case Yes:
 	case No:
 	case NothingDefined:
 		r.Log(Warning, "No vertical flip option defined, defaulting to not flipped!")
-		config.VerticalFlip = defaultVerticalFlip
+		c.VerticalFlip = defaultVerticalFlip
 	default:
 		return errors.New("Bad vertical flip option defined in config!")
 	}
 
-	if config.FramesPerClip == "" {
+	if c.FramesPerClip == "" {
 		r.Log(Warning, "No FramesPerClip defined defined, defaulting to 1!")
-		config.Width = defaultFramesPerClip
+		c.Width = defaultFramesPerClip
 	} else {
-		if integer, err := strconv.Atoi(config.FramesPerClip); integer <= 0 || err != nil {
+		if integer, err := strconv.Atoi(c.FramesPerClip); integer <= 0 || err != nil {
 			return errors.New("Bad width defined in config!")
 		}
 	}
 
-	if config.Width == "" {
+	if c.Width == "" {
 		r.Log(Warning, "No width defined, defaulting to 1280!")
-		config.Width = defaultWidth
+		c.Width = defaultWidth
 	} else {
-		if integer, err := strconv.Atoi(config.Width); integer < 0 || err != nil {
+		if integer, err := strconv.Atoi(c.Width); integer < 0 || err != nil {
 			return errors.New("Bad width defined in config!")
 		}
 	}
 
-	if config.Height == "" {
+	if c.Height == "" {
 		r.Log(Warning, "No height defined, defaulting to 720!")
-		config.Height = defaultHeight
+		c.Height = defaultHeight
 	} else {
-		if integer, err := strconv.Atoi(config.Height); integer < 0 || err != nil {
+		if integer, err := strconv.Atoi(c.Height); integer < 0 || err != nil {
 			return errors.New("Bad height defined in config!")
 		}
 	}
 
-	if config.FrameRate == "" {
+	if c.FrameRate == "" {
 		r.Log(Warning, "No frame rate defined, defaulting to 25!")
-		config.FrameRate = defaultFrameRate
+		c.FrameRate = defaultFrameRate
 	} else {
-		if integer, err := strconv.Atoi(config.FrameRate); integer < 0 || err != nil {
+		if integer, err := strconv.Atoi(c.FrameRate); integer < 0 || err != nil {
 			return errors.New("Bad frame rate defined in config!")
 		}
 	}
 
-	if config.Bitrate == "" {
+	if c.Bitrate == "" {
 		r.Log(Warning, "No bitrate defined, defaulting!")
-		config.Bitrate = defaultBitrate
+		c.Bitrate = defaultBitrate
 	} else {
-		if integer, err := strconv.Atoi(config.Bitrate); integer < 0 || err != nil {
+		if integer, err := strconv.Atoi(c.Bitrate); integer < 0 || err != nil {
 			return errors.New("Bad bitrate defined in config!")
 		}
 	}
 
-	if config.Timeout == "" {
+	if c.Timeout == "" {
 		r.Log(Warning, "No timeout defined, defaulting to 0!")
-		config.Timeout = defaultTimeout
+		c.Timeout = defaultTimeout
 	} else {
-		if integer, err := strconv.Atoi(config.Timeout); integer < 0 || err != nil {
+		if integer, err := strconv.Atoi(c.Timeout); integer < 0 || err != nil {
 			return errors.New("Bad timeout defined in config!")
 		}
 	}
 
-	if config.IntraRefreshPeriod == "" {
+	if c.IntraRefreshPeriod == "" {
 		r.Log(Warning, "No intra refresh defined, defaulting to 100!")
-		config.IntraRefreshPeriod = defaultIntraRefreshPeriod
+		c.IntraRefreshPeriod = defaultIntraRefreshPeriod
 	} else {
-		if integer, err := strconv.Atoi(config.IntraRefreshPeriod); integer < 0 || err != nil {
+		if integer, err := strconv.Atoi(c.IntraRefreshPeriod); integer < 0 || err != nil {
 			return errors.New("Bad intra refresh defined in config!")
 		}
 	}
 
-	if config.Quantization == "" {
+	if c.Quantization == "" {
 		r.Log(Warning, "No quantization defined, defaulting to 35!")
-		config.Quantization = defaultQuantization
+		c.Quantization = defaultQuantization
 	} else {
-		if integer, err := strconv.Atoi(config.Quantization); integer < 0 || integer > 51 || err != nil {
+		if integer, err := strconv.Atoi(c.Quantization); integer < 0 || integer > 51 || err != nil {
 			return errors.New("Bad quantization defined in config!")
 		}
 	}

revid/revid.go

@@ -31,17 +31,13 @@ package revid
 
 import (
 	"bufio"
-	"bytes"
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
-	"net/http"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strconv"
-	"sync"
 	"time"
 
 	"bitbucket.org/ausocean/av/generator"
@@ -86,74 +82,55 @@ const (
 
 // Revid provides methods to control a revid session; providing methods
 // to start, stop and change the state of an instance using the Config struct.
-type Revid interface {
+type Revid struct {
-	Start()
-	Stop()
-	changeState(newconfig Config) error
-	GetConfigRef() *Config
-	Log(logType, m string)
-	IsRunning() bool
-	GetBitrate() int64
-}
-
-// The revid struct provides fields to describe the state of a Revid.
-type revid struct {
 	ffmpegPath     string
 	tempDir        string
 	ringBuffer     *ring.Buffer
 	config         Config
 	isRunning      bool
-	outputFile     *os.File
 	inputFile      *os.File
 	generator      generator.Generator
 	parser         parser.Parser
 	cmd            *exec.Cmd
-	ffmpegCmd      *exec.Cmd
 	inputReader    *bufio.Reader
 	ffmpegStdin    io.WriteCloser
 	outputChan     chan []byte
 	setupInput     func() error
 	setupOutput    func() error
 	getFrame       func() []byte
-	sendClip       func(*ring.Chunk) error
+	destination    loadSender
 	rtmpInst       rtmp.Session
-	mutex          sync.Mutex
-	sendMutex      sync.Mutex
 	currentBitrate int64
 }
 
-// NewRevid returns a pointer to a new revid with the desired
+// NewRevid returns a pointer to a new Revid with the desired
 // configuration, and/or an error if construction of the new instant was not
 // successful.
-func NewRevid(config Config) (r *revid, err error) {
+func New(c Config) (*Revid, error) {
-	r = new(revid)
+	var r Revid
-	r.mutex = sync.Mutex{}
+	err := r.reset(c)
-	r.sendMutex = sync.Mutex{}
-	r.ringBuffer = ring.NewBuffer(ringBufferSize, ringBufferElementSize, writeTimeout)
-	err = r.changeState(config)
 	if err != nil {
-		r = nil
+		return nil, err
-		return
 	}
+	r.ringBuffer = ring.NewBuffer(ringBufferSize, ringBufferElementSize, writeTimeout)
 	r.outputChan = make(chan []byte, outputChanSize)
-	r.isRunning = false
+	return &r, nil
-	return
 }
 
 // Returns the currently saved bitrate from the most recent bitrate check
 // check bitrate output delay in consts for this period
-func (r *revid) GetBitrate() int64 {
+func (r *Revid) GetBitrate() int64 {
 	return r.currentBitrate
 }
 
 // GetConfigRef returns a pointer to the revidInst's Config struct object
-func (r *revid) GetConfigRef() *Config {
+func (r *Revid) GetConfigRef() *Config {
 	return &r.config
 }
 
-// changeState swaps the current config of a revid with the passed
+// reset swaps the current config of a Revid with the passed
 // configuration; checking validity and returning errors if not valid.
-func (r *revid) changeState(config Config) error {
+func (r *Revid) reset(config Config) error {
 	r.config.Logger = config.Logger
 	err := config.Validate(r)
 	if err != nil {
@@ -161,18 +138,33 @@ func (r *revid) changeState(config Config) error {
 	}
 	r.config = config
 
+	if r.destination != nil {
+		err = r.destination.close()
+		if err != nil {
+			r.Log(Error, err.Error())
+		}
+	}
 	switch r.config.Output {
 	case File:
-		r.setupOutput = r.setupOutputForFile
+		s, err := newFileSender(config.OutputFileName)
-		r.sendClip = r.sendClipToFile
+		if err != nil {
+			return err
+		}
+		r.destination = s
 	case FfmpegRtmp:
-		r.setupOutput = r.setupOutputForFfmpegRtmp
+		s, err := newFfmpegSender(config.RtmpUrl, r.config.FrameRate)
-		r.sendClip = r.sendClipToFfmpegRtmp
+		if err != nil {
+			return err
+		}
+		r.destination = s
 	case NativeRtmp:
-		r.setupOutput = r.setupOutputForLibRtmp
+		s, err := newRtmpSender(config.RtmpUrl, rtmpConnectionTimout, rtmpConnectionMaxTries, r.Log)
-		r.sendClip = r.sendClipToLibRtmp
+		if err != nil {
+			return err
+		}
+		r.destination = s
 	case Http:
-		r.sendClip = r.sendClipToHTTP
+		r.destination = newHttpSender(config.RtmpUrl, httpTimeout, r.Log)
 	}
 
 	switch r.config.Input {
@@ -214,25 +206,25 @@ noPacketizationSetup:
 	return nil
 }
 
-// ChangeConfig changes the current configuration of the revid instance.
+// ChangeConfig changes the current configuration of the Revid instance.
-func (r *revid) ChangeConfig(config Config) (err error) {
+func (r *Revid) ChangeConfig(c Config) error {
 	// FIXME(kortschak): This is reimplemented in cmd/revid-cli/main.go.
 	// The implementation in the command is used and this is not.
 	// Decide on one or the other.
 
 	r.Stop()
-	r, err = NewRevid(config)
+	r, err := New(c)
 	if err != nil {
-		return
+		return err
 	}
 	r.Start()
-	return
+	return err
 }
 
 // Log takes a logtype and message and tries to send this information to the
 // logger provided in the revid config - if there is one, otherwise the message
 // is sent to stdout
-func (r *revid) Log(logType, m string) {
+func (r *Revid) Log(logType, m string) {
 	if r.config.Verbosity == Yes {
 		if r.config.Logger != nil {
 			r.config.Logger.Log("revid", logType, m)
@@ -243,28 +235,19 @@ func (r *revid) Log(logType, m string) {
 }
 
 // IsRunning returns true if the revid is currently running and false otherwise
-func (r *revid) IsRunning() bool {
+func (r *Revid) IsRunning() bool {
 	return r.isRunning
 }
 
-// Start invokes a revid to start processing video from a defined input
+// Start invokes a Revid to start processing video from a defined input
 // and packetising (if theres packetization) to a defined output.
-func (r *revid) Start() {
+func (r *Revid) Start() {
-	r.mutex.Lock()
-	defer r.mutex.Unlock()
 	if r.isRunning {
-		r.Log(Warning, "revid.Start() called but revid already running!")
+		r.Log(Warning, "Revid.Start() called but revid already running!")
 		return
 	}
 	r.Log(Info, "Starting Revid!")
 	r.Log(Debug, "Setting up output!")
-	if r.setupOutput != nil {
-		err := r.setupOutput()
-		if err != nil {
-			r.Log(Error, err.Error())
-			return
-		}
-	}
 	r.isRunning = true
 	r.Log(Info, "Starting output routine!")
 	go r.outputClips()
@@ -279,20 +262,13 @@ func (r *revid) Start() {
 }
 
 // Stop halts any processing of video data from a camera or file
-func (r *revid) Stop() {
+func (r *Revid) Stop() {
-	r.mutex.Lock()
-	defer r.mutex.Unlock()
-
 	if !r.isRunning {
-		r.Log(Warning, "revid.Stop() called but revid not running!")
+		r.Log(Warning, "Revid.Stop() called but revid not running!")
 		return
 	}
 
 	r.Log(Info, "Stopping revid!")
-	// wait for sending to finish
-	r.sendMutex.Lock()
-	defer r.sendMutex.Unlock()
-	r.rtmpInst.Close()
 	r.isRunning = false
 
 	r.Log(Info, "Stopping generator!")
@@ -315,18 +291,18 @@ func (r *revid) Stop() {
 
 // getFrameNoPacketization gets a frame directly from the revid output chan
 // as we don't need to go through the generator with no packetization settings
-func (r *revid) getFrameNoPacketization() []byte {
+func (r *Revid) getFrameNoPacketization() []byte {
 	return <-r.outputChan
 }
 
 // getFramePacketization gets a frame from the generators output chan - the
 // the generator being an mpegts or flv generator depending on the config
-func (r *revid) getFramePacketization() []byte {
+func (r *Revid) getFramePacketization() []byte {
 	return <-(r.generator.GetOutputChan())
 }
 
-// flushDataPacketization removes data from the revid inst's coutput chan
+// flushDataPacketization removes data from the Revid inst's coutput chan
-func (r *revid) flushData() {
+func (r *Revid) flushData() {
 	switch r.config.Packetization {
 	case Flv:
 		for {
@@ -342,7 +318,7 @@ done:
 
 // packClips takes data segments; whether that be tsPackets or mjpeg frames and
 // packs them into clips consisting of the amount frames specified in the config
-func (r *revid) packClips() {
+func (r *Revid) packClips() {
 	clipSize := 0
 	packetCount := 0
 	for r.isRunning {
@@ -384,7 +360,7 @@ func (r *revid) packClips() {
 
 // outputClips takes the clips produced in the packClips method and outputs them
 // to the desired output defined in the revid config
-func (r *revid) outputClips() {
+func (r *Revid) outputClips() {
 	now := time.Now()
 	prevTime := now
 	bytes := 0
@@ -409,15 +385,20 @@ func (r *revid) outputClips() {
 
 		bytes += chunk.Len()
 		r.Log(Detail, "About to send")
-		err = r.sendClip(chunk)
+		err = r.destination.load(chunk)
+		if err != nil {
+			r.Log(Error, "failed to load clip")
+		}
+		err = r.destination.send()
 		if err == nil {
-			r.Log(Detail, "Sent clip")
+			r.Log(Detail, "sent clip")
 		}
 
 		if r.isRunning && err != nil && chunk.Len() > 11 {
 			r.Log(Debug, "Send failed! Trying again")
 			// Try and send again
-			err = r.sendClip(chunk)
+			err = r.destination.send()
+			r.Log(Error, err.Error())
 
 			// if there's still an error we try and reconnect, unless we're stopping
 			for r.isRunning && err != nil {
@@ -425,22 +406,26 @@ func (r *revid) outputClips() {
 				time.Sleep(time.Duration(sendFailedDelay) * time.Millisecond)
 				r.Log(Error, err.Error())
 
-				if r.config.Output == NativeRtmp {
+				if rs, ok := r.destination.(restarter); ok {
-					r.Log(Debug, "Ending current rtmp session...")
+					r.Log(Debug, fmt.Sprintf("restarting %T session", rs))
-					r.rtmpInst.Close()
+					err = rs.restart()
-				}
+					if err != nil {
-
+						// TODO(kortschak): Make this "Fatal" when that exists.
-				if r.config.Output == NativeRtmp {
+						r.Log(Error, "failed to restart rtmp session")
-					r.Log(Info, "Restarting rtmp session...")
+						r.isRunning = false
-					r.rtmpInst.StartSession()
+						return
+					}
+					r.Log(Info, "restarted rtmp session")
 				}
 
 				r.Log(Debug, "Trying to send again with new connection...")
-				r.sendClip(chunk) // TODO(kortschak): Log these errors?
+				err = r.destination.send()
+				r.Log(Error, err.Error())
 			}
 		}
 
-		chunk.Close() // ring.Chunk is an io.Closer, but Close alwats returns nil.
+		r.destination.release()
+
 		r.Log(Detail, "Done reading that clip from ringbuffer...")
 
 		// Log some information regarding bitrate and ring buffer size if it's time
@@ -455,134 +440,15 @@ func (r *revid) outputClips() {
 		}
 	}
 	r.Log(Info, "Not outputting clips anymore!")
-}
+	err := r.destination.close()
-
-// senClipToFile writes the passed clip to a file
-func (r *revid) sendClipToFile(clip *ring.Chunk) error {
-	r.sendMutex.Lock()
-	_, err := clip.WriteTo(r.outputFile)
-	r.sendMutex.Unlock()
-	return err
-}
-
-// sendClipToHTTP takes a clip and an output url and posts through http.
-func (r *revid) sendClipToHTTP(clip *ring.Chunk) error {
-	defer r.sendMutex.Unlock()
-	r.sendMutex.Lock()
-
-	client := http.Client{Timeout: httpTimeout}
-	url := r.config.HttpAddress + strconv.Itoa(clip.Len())
-
-	// FIXME(kortschak): This is necessary because Post takes
-	// an io.Reader as a parameter and closes it if it is an
-	// io.Closer (which *ring.Chunk is), ... and because we
-	// use a method value for dispatching the sendClip work.
-	// So to save work in this case, sendClip should be made
-	// a proper method with a behaviour switch based on a
-	// revid field so that we can prepare these bytes only
-	// once for each clip (reusing a buffer field? or tt
-	// might be work using a sync.Pool for the bodies).
-	post := bytes.NewBuffer(make([]byte, 0, clip.Len()))
-	_, err := clip.WriteTo(post)
 	if err != nil {
-		return fmt.Errorf("Error buffering: %v", err)
+		r.Log(Error, "failed to close destination")
 	}
-
-	r.Log(Debug, fmt.Sprintf("Posting %s (%d bytes)\n", url, clip.Len()))
-	resp, err := client.Post(url, "video/mp2t", post)
-	if err != nil {
-		return fmt.Errorf("Error posting to %s: %s", url, err)
-	}
-	defer resp.Body.Close()
-
-	body, err := ioutil.ReadAll(resp.Body)
-	if err == nil {
-		r.Log(Debug, fmt.Sprintf("%s\n", body))
-	} else {
-		r.Log(Error, err.Error())
-	}
-
-	return nil
-}
-
-// sendClipToFfmpegRtmp sends the clip over the current rtmp connection using
-// an ffmpeg process.
-func (r *revid) sendClipToFfmpegRtmp(clip *ring.Chunk) error {
-	r.sendMutex.Lock()
-	_, err := clip.WriteTo(r.ffmpegStdin)
-	r.sendMutex.Unlock()
-	return err
-}
-
-// sendClipToLibRtmp send the clip over the current rtmp connection using the
-// c based librtmp library
-func (r *revid) sendClipToLibRtmp(clip *ring.Chunk) error {
-	r.sendMutex.Lock()
-	_, err := clip.WriteTo(r.rtmpInst)
-	r.sendMutex.Unlock()
-	return err
-}
-
-// setupOutputForFfmpegRtmp sets up output to rtmp using an ffmpeg process
-func (r *revid) setupOutputForFfmpegRtmp() error {
-	r.ffmpegCmd = exec.Command(ffmpegPath,
-		"-f", "h264",
-		"-r", r.config.FrameRate,
-		"-i", "-",
-		"-f", "lavfi",
-		"-i", "aevalsrc=0",
-		"-fflags", "nobuffer",
-		"-vcodec", "copy",
-		"-acodec", "aac",
-		"-map", "0:0",
-		"-map", "1:0",
-		"-strict", "experimental",
-		"-f", "flv",
-		r.config.RtmpUrl,
-	)
-	var err error
-	r.ffmpegStdin, err = r.ffmpegCmd.StdinPipe()
-	if err != nil {
-		r.Log(Error, err.Error())
-		r.Stop()
-		return err
-	}
-	err = r.ffmpegCmd.Start()
-	if err != nil {
-		r.Log(Error, err.Error())
-		r.Stop()
-		return err
-	}
-	return nil
-}
-
-// setupOutputForLibRtmp sets up rtmp output using the wrapper for the c based
-// librtmp library - makes connection and starts comms etc.
-func (r *revid) setupOutputForLibRtmp() error {
-	r.rtmpInst = rtmp.NewSession(r.config.RtmpUrl, rtmpConnectionTimout)
-	err := r.rtmpInst.StartSession()
-	for noOfTries := 0; err != nil && noOfTries < rtmpConnectionMaxTries; noOfTries++ {
-		r.rtmpInst.Close()
-		r.Log(Error, err.Error())
-		r.Log(Info, "Trying to establish rtmp connection again!")
-		r.rtmpInst = rtmp.NewSession(r.config.RtmpUrl, rtmpConnectionTimout)
-		err = r.rtmpInst.StartSession()
-	}
-	if err != nil {
-		return err
-	}
-	return err
-}
-
-// setupOutputForFile sets up an output file to output data to
-func (r *revid) setupOutputForFile() (err error) {
-	r.outputFile, err = os.Create(r.config.OutputFileName)
-	return
 }
 
 // setupInputForRaspivid sets up things for input from raspivid i.e. starts
 // a raspivid process and pipes it's data output.
-func (r *revid) setupInputForRaspivid() error {
+func (r *Revid) setupInputForRaspivid() error {
 	r.Log(Info, "Starting raspivid!")
 	switch r.config.InputCodec {
 	case H264:
@@ -642,27 +508,16 @@ func (r *revid) setupInputForRaspivid() error {
 }
 
 // setupInputForFile sets things up for getting input from a file
-func (r *revid) setupInputForFile() error {
+func (r *Revid) setupInputForFile() error {
 	fps, _ := strconv.Atoi(r.config.FrameRate)
 	r.parser.SetDelay(uint(float64(1000) / float64(fps)))
 	r.readFile()
 	return nil
 }
 
-// testRtmp is useful to check robustness of connections. Intended to be run as
+// readCamera reads data from the defined camera while the Revid is running.
-// goroutine. After every 'delayTime' the rtmp connection is ended and then
-// restarted
-func (r *revid) testRtmp(delayTime uint) {
-	for {
-		time.Sleep(time.Duration(delayTime) * time.Millisecond)
-		r.rtmpInst.Close()
-		r.rtmpInst.StartSession()
-	}
-}
-
-// readCamera reads data from the defined camera while the revid is running.
 // TODO: use ringbuffer here instead of allocating mem every time!
-func (r *revid) readCamera() {
+func (r *Revid) readCamera() {
 	r.Log(Info, "Reading camera data!")
 	for r.isRunning {
 		data := make([]byte, 1)
@@ -679,8 +534,8 @@ func (r *revid) readCamera() {
 	r.Log(Info, "Not trying to read from camera anymore!")
 }
 
-// readFile reads data from the defined file while the revid is running.
+// readFile reads data from the defined file while the Revid is running.
-func (r *revid) readFile() error {
+func (r *Revid) readFile() error {
 	var err error
 	r.inputFile, err = os.Open(r.config.InputFileName)
 	if err != nil {

revid/senders.go

@@ -0,0 +1,294 @@
+/*
+NAME
+  senders.go
+
+DESCRIPTION
+  See Readme.md
+
+AUTHORS
+  Saxon A. Nelson-Milton <saxon@ausocean.org>
+  Alan Noble <alan@ausocean.org>
+
+LICENSE
+  revid is Copyright (C) 2017-2018 the Australian Ocean Lab (AusOcean)
+
+  It is free software: you can redistribute it and/or modify them
+  under the terms of the GNU General Public License as published by the
+  Free Software Foundation, either version 3 of the License, or (at your
+  option) any later version.
+
+  It is distributed in the hope that it will be useful, but WITHOUT
+  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with revid in gpl.txt.  If not, see http://www.gnu.org/licenses.
+*/
+
+package revid
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"os/exec"
+	"strconv"
+	"time"
+
+	"bitbucket.org/ausocean/av/rtmp"
+	"bitbucket.org/ausocean/utils/ring"
+)
+
+// loadSender is a destination to send a *ring.Chunk to.
+// When a loadSender has finished using the *ring.Chunk
+// it must be Closed.
+type loadSender interface {
+	// load assigns the *ring.Chunk to the loadSender.
+	// The load call may fail, but must not mutate the
+	// the chunk.
+	load(*ring.Chunk) error
+
+	// send performs a destination-specific send
+	// operation. It must not mutate the chunk.
+	send() error
+
+	// release releases the *ring.Chunk.
+	release()
+
+	// close cleans up after use of the loadSender.
+	close() error
+}
+
+// restart is an optional interface for loadSenders that
+// can restart their connection.
+type restarter interface {
+	restart() error
+}
+
+// fileSender implements loadSender for a local file destination.
+type fileSender struct {
+	file *os.File
+
+	chunk *ring.Chunk
+}
+
+func newFileSender(path string) (*fileSender, error) {
+	f, err := os.Create(path)
+	if err != nil {
+		return nil, err
+	}
+	return &fileSender{file: f}, nil
+}
+
+func (s *fileSender) load(c *ring.Chunk) error {
+	s.chunk = c
+	return nil
+}
+
+func (s *fileSender) send() error {
+	_, err := s.chunk.WriteTo(s.file)
+	return err
+}
+
+func (s *fileSender) release() {
+	s.chunk.Close()
+	s.chunk = nil
+}
+
+func (s *fileSender) close() error {
+	return s.file.Close()
+}
+
+// httpSender implements loadSender for an HTTP destination.
+type httpSender struct {
+	client http.Client
+	url    string
+
+	log func(lvl, msg string)
+
+	buf []byte
+
+	chunk *ring.Chunk
+}
+
+func newHttpSender(url string, timeout time.Duration, log func(lvl, msg string)) *httpSender {
+	return &httpSender{
+		client: http.Client{Timeout: timeout},
+		url:    url,
+		log:    log,
+	}
+}
+
+func (s *httpSender) load(c *ring.Chunk) error {
+	buf := bytes.NewBuffer(s.buf[:0])
+	_, err := s.chunk.WriteTo(buf)
+	s.buf = buf.Bytes()
+	if err != nil {
+		return fmt.Errorf("fileSender: %v", err)
+	}
+	return nil
+}
+
+func (s *httpSender) send() error {
+	url := s.url + strconv.Itoa(len(s.buf))
+	s.log(Debug, fmt.Sprintf("Posting %s (%d bytes)\n", url, len(s.buf)))
+	resp, err := s.client.Post(url, "video/mp2t", bytes.NewReader(s.buf))
+	if err != nil {
+		return fmt.Errorf("Error posting to %s: %s", url, err)
+	}
+	defer resp.Body.Close()
+
+	body, err := ioutil.ReadAll(resp.Body)
+	if err == nil {
+		s.log(Debug, fmt.Sprintf("%s\n", body))
+	} else {
+		s.log(Error, err.Error())
+	}
+	return err
+}
+
+func (s *httpSender) release() {
+	s.chunk.Close()
+	s.chunk = nil
+}
+
+func (s *httpSender) close() error { return nil }
+
+// ffmpegSender implements loadSender for an FFMPEG RTMP destination.
+type ffmpegSender struct {
+	ffmpeg io.WriteCloser
+
+	chunk *ring.Chunk
+}
+
+func newFfmpegSender(url, framerate string) (*ffmpegSender, error) {
+	cmd := exec.Command(ffmpegPath,
+		"-f", "h264",
+		"-r", framerate,
+		"-i", "-",
+		"-f", "lavfi",
+		"-i", "aevalsrc=0",
+		"-fflags", "nobuffer",
+		"-vcodec", "copy",
+		"-acodec", "aac",
+		"-map", "0:0",
+		"-map", "1:0",
+		"-strict", "experimental",
+		"-f", "flv",
+		url,
+	)
+	w, err := cmd.StdinPipe()
+	if err != nil {
+		return nil, err
+	}
+	err = cmd.Start()
+	if err != nil {
+		return nil, err
+	}
+	return &ffmpegSender{ffmpeg: w}, nil
+}
+
+func (s *ffmpegSender) load(c *ring.Chunk) error {
+	s.chunk = c
+	return nil
+}
+
+func (s *ffmpegSender) send() error {
+	_, err := s.chunk.WriteTo(s.ffmpeg)
+	return err
+}
+
+func (s *ffmpegSender) release() {
+	s.chunk.Close()
+	s.chunk = nil
+}
+
+func (s *ffmpegSender) close() error {
+	return s.ffmpeg.Close()
+}
+
+// rtmpSender implements loadSender for a native RTMP destination.
+type rtmpSender struct {
+	sess rtmp.Session
+
+	url     string
+	timeout uint
+	retries int
+	log     func(lvl, msg string)
+
+	chunk *ring.Chunk
+}
+
+var _ restarter = (*rtmpSender)(nil)
+
+func newRtmpSender(url string, timeout uint, retries int, log func(lvl, msg string)) (*rtmpSender, error) {
+	var sess rtmp.Session
+	var err error
+	for n := 0; n < retries; n++ {
+		sess = rtmp.NewSession(url, timeout)
+		err = sess.StartSession()
+		if err == nil {
+			break
+		}
+		log(Error, err.Error())
+		sess.Close()
+		if n < retries-1 {
+			log(Info, "retry rtmp connection")
+		}
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	s := &rtmpSender{
+		sess:    sess,
+		url:     url,
+		timeout: timeout,
+		retries: retries,
+		log:     log,
+	}
+	return s, nil
+}
+
+func (s *rtmpSender) load(c *ring.Chunk) error {
+	s.chunk = c
+	return nil
+}
+
+func (s *rtmpSender) send() error {
+	_, err := s.chunk.WriteTo(s.sess)
+	return err
+}
+
+func (s *rtmpSender) release() {
+	s.chunk.Close()
+	s.chunk = nil
+}
+
+func (s *rtmpSender) restart() error {
+	err := s.sess.Close()
+	if err != nil {
+		return err
+	}
+	for n := 0; n < s.retries; n++ {
+		s.sess = rtmp.NewSession(s.url, s.timeout)
+		err = s.sess.StartSession()
+		if err == nil {
+			break
+		}
+		s.log(Error, err.Error())
+		s.sess.Close()
+		if n < s.retries-1 {
+			s.log(Info, "retry rtmp connection")
+		}
+	}
+	return err
+}
+
+func (s *rtmpSender) close() error {
+	return s.sess.Close()
+}