2025-04-11 09:28:30 +02:00

398 lines
12 KiB
Go

package mediaserver
import (
"bytes"
"cmp"
"context"
"crypto/rand"
"fmt"
"log/slog"
"net/http"
"strconv"
"time"
typescontainer "github.com/docker/docker/api/types/container"
"github.com/docker/go-connections/nat"
"gopkg.in/yaml.v3"
"git.netflux.io/rob/octoplex/internal/container"
"git.netflux.io/rob/octoplex/internal/domain"
)
// StreamKey is the stream key for the media server, which forms the RTMP path
// component and can be used as a basic form of authentication.
//
// It defaults to "live", in which case the full RTMP URL would be:
// `rtmp://localhost:1935/live`.
type StreamKey string
const (
defaultFetchIngressStateInterval = 5 * time.Second // default interval to fetch the state of the media server
defaultAPIPort = 9997 // default API host port for the media server
defaultRTMPPort = 1935 // default RTMP host port for the media server
defaultChanSize = 64 // default channel size for asynchronous non-error channels
imageNameMediaMTX = "ghcr.io/rfwatson/mediamtx-alpine:latest" // image name for mediamtx
defaultStreamKey StreamKey = "live" // Default stream key. See [StreamKey].
componentName = "mediaserver" // component name, mostly used for Docker labels
httpClientTimeout = time.Second // timeout for outgoing HTTP client requests
)
// action is an action to be performed by the actor.
type action func()
// Actor is responsible for managing the media server.
type Actor struct {
actorC chan action
stateC chan domain.Source
chanSize int
containerClient *container.Client
apiPort int
rtmpPort int
streamKey StreamKey
fetchIngressStateInterval time.Duration
pass string // password for the media server
tlsCert, tlsKey []byte // TLS cert and key for the media server
logger *slog.Logger
apiClient *http.Client
// mutable state
state *domain.Source
}
// NewActorParams contains the parameters for building a new media server
// actor.
type NewActorParams struct {
APIPort int // defaults to 9997
RTMPPort int // defaults to 1935
StreamKey StreamKey // defaults to "live"
ChanSize int // defaults to 64
FetchIngressStateInterval time.Duration // defaults to 5 seconds
ContainerClient *container.Client
Logger *slog.Logger
}
// NewActor creates a new media server actor.
//
// Callers must consume the state channel exposed via [C].
func NewActor(ctx context.Context, params NewActorParams) (_ *Actor, err error) {
tlsCert, tlsKey, err := generateTLSCert()
if err != nil {
return nil, fmt.Errorf("generate TLS cert: %w", err)
}
apiClient, err := buildAPIClient(tlsCert)
if err != nil {
return nil, fmt.Errorf("build API client: %w", err)
}
chanSize := cmp.Or(params.ChanSize, defaultChanSize)
return &Actor{
apiPort: cmp.Or(params.APIPort, defaultAPIPort),
rtmpPort: cmp.Or(params.RTMPPort, defaultRTMPPort),
streamKey: cmp.Or(params.StreamKey, defaultStreamKey),
fetchIngressStateInterval: cmp.Or(params.FetchIngressStateInterval, defaultFetchIngressStateInterval),
tlsCert: tlsCert,
tlsKey: tlsKey,
pass: generatePassword(),
actorC: make(chan action, chanSize),
state: new(domain.Source),
stateC: make(chan domain.Source, chanSize),
chanSize: chanSize,
containerClient: params.ContainerClient,
logger: params.Logger,
apiClient: apiClient,
}, nil
}
func (a *Actor) Start(ctx context.Context) error {
// Exposed ports are bound to 127.0.0.1 for security.
// TODO: configurable RTMP bind address
apiPortSpec := nat.Port("127.0.0.1:" + strconv.Itoa(a.apiPort) + ":9997")
rtmpPortSpec := nat.Port("127.0.0.1:" + strconv.Itoa(+a.rtmpPort) + ":1935")
exposedPorts, portBindings, _ := nat.ParsePortSpecs([]string{string(apiPortSpec), string(rtmpPortSpec)})
// The RTMP URL is passed to the UI via the state.
// This could be refactored, it's not really stateful data.
a.state.RTMPURL = a.RTMPURL()
cfg, err := yaml.Marshal(
Config{
LogLevel: "info",
LogDestinations: []string{"stdout"},
AuthMethod: "internal",
AuthInternalUsers: []User{
{
User: "any",
IPs: []string{}, // any IP
Permissions: []UserPermission{
{Action: "publish"},
},
},
{
User: "api",
Pass: a.pass,
IPs: []string{}, // any IP
Permissions: []UserPermission{
{Action: "read"},
},
},
{
User: "api",
Pass: a.pass,
IPs: []string{}, // any IP
Permissions: []UserPermission{{Action: "api"}},
},
},
API: true,
APIEncryption: true,
APIServerCert: "/etc/tls.crt",
APIServerKey: "/etc/tls.key",
Paths: map[string]Path{
string(a.streamKey): {Source: "publisher"},
},
},
)
if err != nil { // should never happen
return fmt.Errorf("marshal config: %w", err)
}
containerStateC, errC := a.containerClient.RunContainer(
ctx,
container.RunContainerParams{
Name: componentName,
ChanSize: a.chanSize,
ContainerConfig: &typescontainer.Config{
Image: imageNameMediaMTX,
Hostname: "mediaserver",
Labels: map[string]string{container.LabelComponent: componentName},
Healthcheck: &typescontainer.HealthConfig{
Test: []string{
"CMD",
"curl",
"--fail",
"--silent",
"--cacert", "/etc/tls.crt",
"--config", "/etc/healthcheckopts.txt",
a.healthCheckURL(),
},
Interval: time.Second * 10,
StartPeriod: time.Second * 2,
StartInterval: time.Second * 2,
Retries: 2,
},
ExposedPorts: exposedPorts,
},
HostConfig: &typescontainer.HostConfig{
NetworkMode: "default",
PortBindings: portBindings,
},
NetworkCountConfig: container.NetworkCountConfig{Rx: "eth0", Tx: "eth1"},
CopyFileConfigs: []container.CopyFileConfig{
{
Path: "/mediamtx.yml",
Payload: bytes.NewReader(cfg),
Mode: 0600,
},
{
Path: "/etc/tls.crt",
Payload: bytes.NewReader(a.tlsCert),
Mode: 0600,
},
{
Path: "/etc/tls.key",
Payload: bytes.NewReader(a.tlsKey),
Mode: 0600,
},
{
Path: "/etc/healthcheckopts.txt",
Payload: bytes.NewReader([]byte(fmt.Sprintf("--user api:%s", a.pass))),
Mode: 0600,
},
},
},
)
go a.actorLoop(ctx, containerStateC, errC)
return nil
}
// C returns a channel that will receive the current state of the media server.
func (s *Actor) C() <-chan domain.Source {
return s.stateC
}
// State returns the current state of the media server.
//
// Blocks if the actor is not started yet.
func (s *Actor) State() domain.Source {
resultChan := make(chan domain.Source)
s.actorC <- func() {
resultChan <- *s.state
}
return <-resultChan
}
// Close closes the media server actor.
func (s *Actor) Close() error {
if err := s.containerClient.RemoveContainers(
context.Background(),
s.containerClient.ContainersWithLabels(map[string]string{container.LabelComponent: componentName}),
); err != nil {
return fmt.Errorf("remove containers: %w", err)
}
return nil
}
// actorLoop is the main loop of the media server actor. It exits when the
// actor is closed, or the parent context is cancelled.
func (s *Actor) actorLoop(ctx context.Context, containerStateC <-chan domain.Container, errC <-chan error) {
fetchStateT := time.NewTicker(s.fetchIngressStateInterval)
defer fetchStateT.Stop()
// fetchTracksT is used to signal that tracks should be fetched from the
// media server, after the stream goes on-air. A short delay is needed due to
// workaround a race condition in the media server.
var fetchTracksT *time.Timer
resetFetchTracksT := func(d time.Duration) { fetchTracksT = time.NewTimer(d) }
resetFetchTracksT(time.Second)
fetchTracksT.Stop()
sendState := func() { s.stateC <- *s.state }
for {
select {
case containerState := <-containerStateC:
s.state.Container = containerState
if s.state.Container.Status == domain.ContainerStatusExited {
fetchStateT.Stop()
s.handleContainerExit(nil)
}
sendState()
continue
case err, ok := <-errC:
if !ok {
// The loop continues until the actor is closed.
// Avoid receiving duplicate close signals.
errC = nil
continue
}
if err != nil {
s.logger.Error("Error from container client", "err", err, "id", shortID(s.state.Container.ID))
}
fetchStateT.Stop()
s.handleContainerExit(err)
sendState()
case <-fetchStateT.C:
ingressState, err := fetchIngressState(s.rtmpConnsURL(), s.streamKey, s.apiClient)
if err != nil {
s.logger.Error("Error fetching server state", "err", err)
continue
}
var shouldSendState bool
if ingressState.ready != s.state.Live {
s.state.Live = ingressState.ready
s.state.LiveChangedAt = time.Now()
resetFetchTracksT(time.Second)
shouldSendState = true
}
if ingressState.listeners != s.state.Listeners {
s.state.Listeners = ingressState.listeners
shouldSendState = true
}
if shouldSendState {
sendState()
}
case <-fetchTracksT.C:
if !s.state.Live {
continue
}
if tracks, err := fetchTracks(s.pathsURL(), s.streamKey, s.apiClient); err != nil {
s.logger.Error("Error fetching tracks", "err", err)
resetFetchTracksT(3 * time.Second)
} else if len(tracks) == 0 {
resetFetchTracksT(time.Second)
} else {
s.state.Tracks = tracks
sendState()
}
case action, ok := <-s.actorC:
if !ok {
continue
}
action()
case <-ctx.Done():
return
}
}
}
// TODO: refactor to use container.Err?
func (s *Actor) handleContainerExit(err error) {
if s.state.Container.ExitCode != nil {
s.state.ExitReason = fmt.Sprintf("Server process exited with code %d.", *s.state.Container.ExitCode)
} else {
s.state.ExitReason = "Server process exited unexpectedly."
}
if err != nil {
s.state.ExitReason += "\n\n" + err.Error()
}
s.state.Live = false
}
// RTMPURL returns the RTMP URL for the media server, accessible from the host.
func (s *Actor) RTMPURL() string {
return fmt.Sprintf("rtmp://localhost:%d/%s", s.rtmpPort, s.streamKey)
}
// RTMPInternalURL returns the RTMP URL for the media server, accessible from
// the app network.
func (s *Actor) RTMPInternalURL() string {
// Container port, not host port:
return fmt.Sprintf("rtmp://mediaserver:1935/%s?user=api&pass=%s", s.streamKey, s.pass)
}
// rtmpConnsURL returns the URL for fetching RTMP connections, accessible from
// the host.
func (s *Actor) rtmpConnsURL() string {
return fmt.Sprintf("https://api:%s@localhost:%d/v3/rtmpconns/list", s.pass, s.apiPort)
}
// pathsURL returns the URL for fetching paths, accessible from the host.
func (s *Actor) pathsURL() string {
return fmt.Sprintf("https://api:%s@localhost:%d/v3/paths/list", s.pass, s.apiPort)
}
// healthCheckURL returns the URL for the health check, accessible from the
// container. It is logged to Docker's events log so must not include
// credentials.
func (s *Actor) healthCheckURL() string {
return fmt.Sprintf("https://localhost:%d/v3/paths/list", s.apiPort)
}
// shortID returns the first 12 characters of the given container ID.
func shortID(id string) string {
if len(id) < 12 {
return id
}
return id[:12]
}
// generatePassword securely generates a random password suitable for
// authenticating media server endpoints.
func generatePassword() string {
const lenBytes = 32
p := make([]byte, lenBytes)
_, _ = rand.Read(p)
return fmt.Sprintf("%x", []byte(p))
}