【编者的话】containerd v1.0.0的源码分析，以docker-containerd --config /var/run/docker/containerd/containerd.toml为入口，看大神们如何组织Go语言代码
containerd.io
github: containerd v1.0.0
准备:
go get -v github.com/containerd/containerd
cd $GOPATH/src/github.com/containerd/containerd
git checkout v1.0.0 -b v1.0.0
分析
命令行
- 位置：
cmd/containerd/main.go - 作用：定义containerd 命令行相关参数与配置文件
- 依赖：github.com/urfave/cli
package main
import (
"fmt"
"os"
"github.com/containerd/containerd/version"
"github.com/urfave/cli"
)
const usage = `
__ _ __
_________ ____ / /_____ _(_)___ ___ _________/ /
/ ___/ __ \/ __ \/ __/ __ ` + "`" + `/ / __ \/ _ \/ ___/ __ /
/ /__/ /_/ / / / / /_/ /_/ / / / / / __/ / / /_/ /
\___/\____/_/ /_/\__/\__,_/_/_/ /_/\___/_/ \__,_/
high performance container runtime
`
func main() {
app := cli.NewApp()
app.Name = "containerd"
app.Version = version.Version
app.Usage = usage
app.Flags = []cli.Flag{
cli.StringFlag{
Name: "config,c",
Usage: "path to the configuration file",
Value: defaultConfigPath,
},
}
app.Commands = []cli.Command{}
app.Action = func(context *cli.Context) error {
return nil
}
if err := app.Run(os.Args); err != nil {
fmt.Fprintf(os.Stderr, "containerd: %s\n", err)
os.Exit(1)
}
}
配置文件解析
- 位置：
server/config.go - 作用：解析配置文件相关参数
- 依赖：
github.com/BurntSushi/toml
github.com/pkg/errors
// LoadConfig loads the containerd server config from the provided path
func LoadConfig(path string, v *Config) error {
if v == nil {
return errors.Wrapf(errdefs.ErrInvalidArgument, "argument v must not be nil")
}
md, err := toml.DecodeFile(path, v)
if err != nil {
return err
}
v.md = md
return nil
}
添加参数
- 位置：
cmd/containerd/main.go - 作用：应用参数到相关配置
func applyFlags(context *cli.Context, config *server.Config) error {
// the order for config vs flag values is that flags will always override
// the config values if they are set
if err := setLevel(context, config); err != nil {
return err
}
for _, v := range []struct {
name string
d *string
}{
{
name: "root",
d: &config.Root,
},
{
name: "state",
d: &config.State,
},
{
name: "address",
d: &config.GRPC.Address,
},
} {
if s := context.GlobalString(v.name); s != "" {
*v.d = s
}
}
return nil
}
日志
- 位置：
log/context.go - 作用：应用日志
- 依赖： github.com/sirupsen/logrus
...
var ctx = log.WithModule(gocontext.Background(), "containerd")
...
log.G(ctx).WithFields(logrus.Fields{
"version": version.Version,
"revision": version.Revision,
}).Info("starting containerd")
...
# log/context.go
func WithModule(ctx context.Context, module string) context.Context {
parent := GetModulePath(ctx)
if parent != "" {
if path.Base(parent) == module {
return ctx
}
module = path.Join(parent, module)
}
ctx = WithLogger(ctx, GetLogger(ctx).WithField("module", module))
return context.WithValue(ctx, moduleKey{}, module)
}
