boulder/cmd/shell.go

125 lines
2.8 KiB
Go

// Copyright 2014 ISRG. All rights reserved
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This package provides utilities that underlie the specific commands.
// The idea is to make the specific command files very small, e.g.:
//
// func main() {
// app := cmd.NewAppShell("command-name")
// app.Action = func(c cmd.Config) {
// // command logic
// }
// app.Run()
// }
//
// All commands share the same invocation pattern. They take a single
// parameter "-config", which is the name of a JSON file containing
// the configuration for the app. This JSON file is unmarshalled into
// a Config object, which is provided to the app.
package cmd
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"github.com/codegangsta/cli"
"github.com/letsencrypt/boulder/rpc"
"github.com/streadway/amqp"
)
// Config stores configuration parameters that applications
// will need. For simplicity, we just lump them all into
// one struct, and use encoding/json to read it from a file.
//
// Note: NO DEFAULTS are provided.
type Config struct {
// General
AMQPServer string
WFE struct {
BaseURL string
ListenAddress string
}
CA struct {
Server string
AuthKey string
Profile string
}
SA struct {
DBDriver string
DBName string
}
}
type AppShell struct {
Action func(Config)
app *cli.App
}
func NewAppShell(name string) (shell *AppShell) {
app := cli.NewApp()
app.Name = name
app.Version = "0.0.0"
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "config",
Value: "config.json",
EnvVar: "BOULDER_CONFIG",
},
}
return &AppShell{app: app}
}
func (as *AppShell) Run() {
as.app.Action = func(c *cli.Context) {
configFileName := c.GlobalString("config")
configJSON, err := ioutil.ReadFile(configFileName)
FailOnError(err, "Unable to read config file")
var config Config
err = json.Unmarshal(configJSON, &config)
as.Action(config)
}
err := as.app.Run(os.Args)
FailOnError(err, "Failed to run application")
}
// Exit and print error message if we encountered a problem
func FailOnError(err error, msg string) {
if err != nil {
fmt.Fprintf(os.Stderr, "%s: %s\n", msg, err)
os.Exit(1)
}
}
// This is the same as amqpConnect in boulder, but with even
// more aggressive error dropping
func AmqpChannel(url string) (ch *amqp.Channel) {
conn, err := amqp.Dial(url)
FailOnError(err, "Unable to connect to AMQP server")
ch, err = conn.Channel()
FailOnError(err, "Unable to establish channel to AMQP server")
return
}
// Start the server and wait around
func RunForever(server *rpc.AmqpRPCServer) {
forever := make(chan bool)
server.Start()
fmt.Fprintf(os.Stderr, "Server running...\n")
<-forever
}