dotcloud/docker

package logger // import "github.com/docker/docker/daemon/logger"

import (
    "fmt"
    "sort"
    "sync"

    containertypes "github.com/docker/docker/api/types/container"
    "github.com/docker/docker/pkg/plugingetter"
    units "github.com/docker/go-units"
    "github.com/pkg/errors"
)

// Creator builds a logging driver instance with given context.
type Creator func(Info) (Logger, error)

// LogOptValidator checks the options specific to the underlying
// logging implementation.
type LogOptValidator func(cfg map[string]string) error

type logdriverFactory struct {
    registry     map[string]Creator
    optValidator map[string]LogOptValidator
    m            sync.Mutex
}

func (lf *logdriverFactory) list() []string {
    ls := make([]string, 0, len(lf.registry))
    lf.m.Lock()
    for name := range lf.registry {
        ls = append(ls, name)
    }
    lf.m.Unlock()
    sort.Strings(ls)
    return ls
}

// ListDrivers gets the list of registered log driver names
func ListDrivers() []string {
    return factory.list()
}

func (lf *logdriverFactory) register(name string, c Creator) error {
    registered, err := lf.driverRegistered(name)
    if err != nil {
        return err
    }
    if registered {
        return fmt.Errorf("logger: log driver named '%s' is already registered", name)
    }

    lf.m.Lock()
    lf.registry[name] = c
    lf.m.Unlock()
    return nil
}

func (lf *logdriverFactory) driverRegistered(name string) (bool, error) {
    lf.m.Lock()
    _, ok := lf.registry[name]
    lf.m.Unlock()
    if !ok {
        if pluginGetter != nil { // this can be nil when the init functions are running
            l, err := getPlugin(name, plugingetter.Lookup)
            if err != nil {
                return false, err
            }
            if l != nil {
                return true, nil
            }
        }
    }
    return ok, nil
}

func (lf *logdriverFactory) registerLogOptValidator(name string, l LogOptValidator) error {
    lf.m.Lock()
    defer lf.m.Unlock()

    if _, ok := lf.optValidator[name]; ok {
        return fmt.Errorf("logger: log validator named '%s' is already registered", name)
    }
    lf.optValidator[name] = l
    return nil
}

func (lf *logdriverFactory) get(name string) (Creator, error) {
    lf.m.Lock()
    defer lf.m.Unlock()

    c, ok := lf.registry[name]
    if ok {
        return c, nil
    }

    c, err := getPlugin(name, plugingetter.Acquire)
    return c, errors.Wrapf(err, "logger: no log driver named '%s' is registered", name)
}

func (lf *logdriverFactory) getLogOptValidator(name string) LogOptValidator {
    lf.m.Lock()
    defer lf.m.Unlock()

    c := lf.optValidator[name]
    return c
}

var factory = &logdriverFactory{registry: make(map[string]Creator), optValidator: make(map[string]LogOptValidator)} // global factory instance

// RegisterLogDriver registers the given logging driver builder with given logging
// driver name.
func RegisterLogDriver(name string, c Creator) error {
    return factory.register(name, c)
}

// RegisterLogOptValidator registers the logging option validator with
// the given logging driver name.
func RegisterLogOptValidator(name string, l LogOptValidator) error {
    return factory.registerLogOptValidator(name, l)
}

// GetLogDriver provides the logging driver builder for a logging driver name.
func GetLogDriver(name string) (Creator, error) {
    return factory.get(name)
}

var builtInLogOpts = map[string]bool{
    "mode":            true,
    "max-buffer-size": true,
}

// ValidateLogOpts checks the options for the given log driver. The
// options supported are specific to the LogDriver implementation.
func ValidateLogOpts(name string, cfg map[string]string) error {
    if name == "none" {
        return nil
    }

    switch containertypes.LogMode(cfg["mode"]) {
    case containertypes.LogModeBlocking, containertypes.LogModeNonBlock, containertypes.LogModeUnset:
    default:
        return fmt.Errorf("logger: logging mode not supported: %s", cfg["mode"])
    }

    if s, ok := cfg["max-buffer-size"]; ok {
        if containertypes.LogMode(cfg["mode"]) != containertypes.LogModeNonBlock {
            return fmt.Errorf("logger: max-buffer-size option is only supported with 'mode=%s'", containertypes.LogModeNonBlock)
        }
        if _, err := units.RAMInBytes(s); err != nil {
            return errors.Wrap(err, "error parsing option max-buffer-size")
        }
    }

    if err := validateExternal(cfg); err != nil {
        return err
    }

    registered, err := factory.driverRegistered(name)
    if err != nil {
        return err
    }
    if !registered {
        return fmt.Errorf("logger: no log driver named '%s' is registered", name)
    }

    filteredOpts := make(map[string]string, len(builtInLogOpts))
    for k, v := range cfg {
        if !builtInLogOpts[k] {
            filteredOpts[k] = v
        }
    }

    validator := factory.getLogOptValidator(name)
    if validator != nil {
        return validator(filteredOpts)
    }
    return nil
}