haproxy.go

// Copyright © 2018 Tuenti Technologies S.L.
//
// Licensed 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 main

import (
	"fmt"
	"os/exec"
)

const (
	StateIdle = iota
	StateReloading
	StateWaiting
)

type HaproxyServer interface {
	Start() error
	Stop() error
	Reload() error
	IsRunning() bool
}

func NewHaproxyServer(path, pidFile, configFile, mode string) (HaproxyServer, error) {
	switch mode {
	case "daemon":
		return &HaproxyServerDaemon{
			path:       path,
			pidFile:    pidFile,
			configFile: configFile,
		}, nil
	case "master-worker":
		return &HaproxyServerMasterWorker{
			path:       path,
			pidFile:    pidFile,
			configFile: configFile,
		}, nil
	default:
		return nil, fmt.Errorf("unknown haproxy mode: %s", mode)
	}
}

// A HaproxyConfigValidator can be used to validate haproxy's configuration
// to ensure haproxy will be able to reload successfully.
type HaproxyConfigValidator interface {
	// Validate returns an error if haproxy has an unusable configuration.
	Validate() error
}

// HaproxyDashC validates haproxy configuration by running haproxy -c.
type HaproxyDashC struct {
	path       string
	configFile string
}

// NewHaproxyDashC implements HaproxyConfigValidator by running haproxy -c to
// to validate haproxy config.
func NewHaproxyDashC(path, configFile string) *HaproxyDashC {
	return &HaproxyDashC{path: path, configFile: configFile}
}

// Validate returns an error if haproxy has an unusable configuration.
func (v *HaproxyDashC) Validate() error {
	args := []string{"-c", "-q", "-f", v.configFile}
	command := exec.Command(v.path, args...)
	if out, err := command.CombinedOutput(); err != nil {
		return fmt.Errorf("%v:\n%s", err, out)
	}
	return nil
}