package main import ( "fmt" "os" "os/exec" "time" ) const ( describeTimeout = 5 * time.Second sourceStopAfterDescribeSecs = 10 * time.Second onDemandCmdStopAfterDescribeSecs = 10 * time.Second ) // a publisher is either a client or a source type publisher interface { isPublisher() } type path struct { p *program name string confp *confPath permanent bool source *source publisher publisher publisherReady bool publisherTrackCount int publisherSdp []byte lastDescribeReq time.Time lastDescribeActivation time.Time onInitCmd *exec.Cmd onDemandCmd *exec.Cmd } func newPath(p *program, name string, confp *confPath, permanent bool) *path { pa := &path{ p: p, name: name, confp: confp, permanent: permanent, } if confp.Source != "record" { s := newSource(p, pa, confp) pa.source = s pa.publisher = s } return pa } func (pa *path) log(format string, args ...interface{}) { pa.p.log("[path "+pa.name+"] "+format, args...) } func (pa *path) onInit() { if pa.source != nil { go pa.source.run(pa.source.state) } if pa.confp.RunOnInit != "" { pa.log("starting on init command") var err error pa.onInitCmd, err = startExternalCommand(pa.confp.RunOnInit, pa.name) if err != nil { pa.log("ERR: %s", err) } } } func (pa *path) onClose(wait bool) { if pa.source != nil { close(pa.source.terminate) <-pa.source.done } if pa.onInitCmd != nil { pa.log("stopping on init command (closing)") pa.onInitCmd.Process.Signal(os.Interrupt) pa.onInitCmd.Wait() } if pa.onDemandCmd != nil { pa.log("stopping on demand command (closing)") pa.onDemandCmd.Process.Signal(os.Interrupt) pa.onDemandCmd.Wait() } for c := range pa.p.clients { if c.path == pa { if c.state == clientStateWaitDescription { c.path = nil c.state = clientStateInitial c.describe <- describeRes{nil, fmt.Errorf("publisher of path '%s' has timed out", pa.name)} } else { c.close() if wait { <-c.done } } } } } func (pa *path) hasClients() bool { for c := range pa.p.clients { if c.path == pa { return true } } return false } func (pa *path) hasClientsWaitingDescribe() bool { for c := range pa.p.clients { if c.state == clientStateWaitDescription && c.path == pa { return true } } return false } func (pa *path) hasClientReaders() bool { for c := range pa.p.clients { if c.path == pa && c != pa.publisher { return true } } return false } func (pa *path) onCheck() { // reply to DESCRIBE requests if they are in timeout if pa.hasClientsWaitingDescribe() && time.Since(pa.lastDescribeActivation) >= describeTimeout { for c := range pa.p.clients { if c.state == clientStateWaitDescription && c.path == pa { c.path = nil c.state = clientStateInitial c.describe <- describeRes{nil, fmt.Errorf("publisher of path '%s' has timed out", pa.name)} } } } // stop on demand source if needed if pa.source != nil && pa.confp.SourceOnDemand && pa.source.state == sourceStateRunning && !pa.hasClients() && time.Since(pa.lastDescribeReq) >= sourceStopAfterDescribeSecs { pa.log("stopping on demand source since (not requested anymore)") pa.source.state = sourceStateStopped pa.source.setState <- pa.source.state } // stop on demand command if needed if pa.onDemandCmd != nil && !pa.hasClientReaders() && time.Since(pa.lastDescribeReq) >= onDemandCmdStopAfterDescribeSecs { pa.log("stopping on demand command (not requested anymore)") pa.onDemandCmd.Process.Signal(os.Interrupt) pa.onDemandCmd.Wait() pa.onDemandCmd = nil } // remove non-permanent paths if !pa.permanent && pa.publisher == nil && !pa.hasClients() { pa.onClose(false) delete(pa.p.paths, pa.name) } } func (pa *path) onPublisherRemove() { pa.publisher = nil // close all clients that are reading or waiting for reading for c := range pa.p.clients { if c.path == pa && c.state != clientStateWaitDescription && c != pa.publisher { c.close() } } } func (pa *path) onPublisherSetReady() { pa.publisherReady = true // reply to all clients that are waiting for a description for c := range pa.p.clients { if c.state == clientStateWaitDescription && c.path == pa { c.path = nil c.state = clientStateInitial c.describe <- describeRes{pa.publisherSdp, nil} } } } func (pa *path) onPublisherSetNotReady() { pa.publisherReady = false // close all clients that are reading or waiting for reading for c := range pa.p.clients { if c.path == pa && c.state != clientStateWaitDescription && c != pa.publisher { c.close() } } } func (pa *path) onDescribe(client *client) { pa.lastDescribeReq = time.Now() // publisher not found if pa.publisher == nil { // on demand command is available: put the client on hold if pa.confp.RunOnDemand != "" { if pa.onDemandCmd == nil { // start if needed pa.log("starting on demand command") pa.lastDescribeActivation = time.Now() var err error pa.onDemandCmd, err = startExternalCommand(pa.confp.RunOnDemand, pa.name) if err != nil { pa.log("ERR: %s", err) } } client.path = pa client.state = clientStateWaitDescription // no on-demand: reply with 404 } else { client.describe <- describeRes{nil, fmt.Errorf("no one is publishing on path '%s'", pa.name)} } // publisher was found but is not ready: put the client on hold } else if !pa.publisherReady { if pa.source != nil && pa.source.state == sourceStateStopped { // start if needed pa.log("starting on demand source") pa.lastDescribeActivation = time.Now() pa.source.state = sourceStateRunning pa.source.setState <- pa.source.state } client.path = pa client.state = clientStateWaitDescription // publisher was found and is ready } else { client.describe <- describeRes{pa.publisherSdp, nil} } }