package logger import ( "fmt" "io" "os" "path/filepath" "strings" "github.com/docker/docker/api/types/plugins/logdriver" getter "github.com/docker/docker/pkg/plugingetter" "github.com/docker/docker/pkg/stringid" "github.com/pkg/errors" ) var pluginGetter getter.PluginGetter const extName = "LogDriver" // logPlugin defines the available functions that logging plugins must implement. type logPlugin interface { StartLogging(streamPath string, info Info) (err error) StopLogging(streamPath string) (err error) Capabilities() (cap Capability, err error) ReadLogs(info Info, config ReadConfig) (stream io.ReadCloser, err error) } // RegisterPluginGetter sets the plugingetter func RegisterPluginGetter(plugingetter getter.PluginGetter) { pluginGetter = plugingetter } // GetDriver returns a logging driver by its name. // If the driver is empty, it looks for the local driver. func getPlugin(name string, mode int) (Creator, error) { p, err := pluginGetter.Get(name, extName, mode) if err != nil { return nil, fmt.Errorf("error looking up logging plugin %s: %v", name, err) } d := &logPluginProxy{p.Client()} return makePluginCreator(name, d, p.BasePath()), nil } func makePluginCreator(name string, l *logPluginProxy, basePath string) Creator { return func(logCtx Info) (logger Logger, err error) { defer func() { if err != nil { pluginGetter.Get(name, extName, getter.Release) } }() root := filepath.Join(basePath, "run", "docker", "logging") if err := os.MkdirAll(root, 0700); err != nil { return nil, err } id := stringid.GenerateNonCryptoID() a := &pluginAdapter{ driverName: name, id: id, plugin: l, basePath: basePath, fifoPath: filepath.Join(root, id), logInfo: logCtx, } cap, err := a.plugin.Capabilities() if err == nil { a.capabilities = cap } stream, err := openPluginStream(a) if err != nil { return nil, err } a.stream = stream a.enc = logdriver.NewLogEntryEncoder(a.stream) if err := l.StartLogging(strings.TrimPrefix(a.fifoPath, basePath), logCtx); err != nil { return nil, errors.Wrapf(err, "error creating logger") } if cap.ReadLogs { return &pluginAdapterWithRead{a}, nil } return a, nil } }