youtubebeat/vendor/github.com/elastic/beats/libbeat/autodiscover/appender.go

108 lines
3 KiB
Go

// Licensed to Elasticsearch B.V. under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Elasticsearch B.V. licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
package autodiscover
import (
"fmt"
"strings"
"github.com/elastic/beats/libbeat/common"
"github.com/elastic/beats/libbeat/common/bus"
"github.com/elastic/beats/libbeat/logp"
)
// Appender provides an interface by which extra configuration can be added into configs
type Appender interface {
// Append takes a processed event and add extra configuration
Append(event bus.Event)
}
// Appenders is a list of Appender objects
type Appenders []Appender
// AppenderBuilder is a func used to generate a Appender object
type AppenderBuilder func(*common.Config) (Appender, error)
// AddBuilder registers a new AppenderBuilder
func (r *registry) AddAppender(name string, appender AppenderBuilder) error {
r.lock.Lock()
defer r.lock.Unlock()
if name == "" {
return fmt.Errorf("appender name is required")
}
_, exists := r.appenders[name]
if exists {
return fmt.Errorf("appender '%s' is already registered", name)
}
if appender == nil {
return fmt.Errorf("appender '%s' cannot be registered with a nil factory", name)
}
r.appenders[name] = appender
logp.Debug(debugK, "Appender registered: %s", name)
return nil
}
// GetAppender returns the appender with the giving name, nil if it doesn't exist
func (r *registry) GetAppender(name string) AppenderBuilder {
r.lock.RLock()
defer r.lock.RUnlock()
name = strings.ToLower(name)
return r.appenders[name]
}
// BuildAppender reads provider configuration and instantiate one
func (r *registry) BuildAppender(c *common.Config) (Appender, error) {
var config AppenderConfig
err := c.Unpack(&config)
if err != nil {
return nil, err
}
appender := r.GetAppender(config.Type)
if appender == nil {
return nil, fmt.Errorf("unknown autodiscover appender %s", config.Type)
}
return appender(c)
}
// Append uses all initialized appenders to modify generated bus.Events.
func (a Appenders) Append(event bus.Event) {
for _, appender := range a {
appender.Append(event)
}
}
// NewAppenders instances and returns the given list of appenders.
func NewAppenders(aConfigs []*common.Config) (Appenders, error) {
var appenders Appenders
for _, acfg := range aConfigs {
appender, err := Registry.BuildAppender(acfg)
if err != nil {
return nil, err
}
appenders = append(appenders, appender)
}
return appenders, nil
}