// Copyright 2018 Google Inc. // // 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. // Helper tool to configure Docker daemon. package main import ( "encoding/json" "fmt" "io/ioutil" "log" "os" "context" "flag" "github.com/google/subcommands" ) var ( configFile = flag.String("config_file", "/etc/docker/daemon.json", "path to Docker daemon config file") ) func main() { subcommands.Register(subcommands.HelpCommand(), "") subcommands.Register(subcommands.FlagsCommand(), "") subcommands.Register(&runtimeAdd{}, "") subcommands.Register(&runtimeRemove{}, "") // All subcommands must be registered before flag parsing. flag.Parse() exitCode := subcommands.Execute(context.Background()) os.Exit(int(exitCode)) } type runtime struct { Path string `json:"path,omitempty"` RuntimeArgs []string `json:"runtimeArgs,omitempty"` } // runtimeAdd implements subcommands.Command. type runtimeAdd struct { } // Name implements subcommands.Command.Name. func (*runtimeAdd) Name() string { return "runtime-add" } // Synopsis implements subcommands.Command.Synopsis. func (*runtimeAdd) Synopsis() string { return "adds a runtime to docker daemon configuration" } // Usage implements subcommands.Command.Usage. func (*runtimeAdd) Usage() string { return `runtime-add [flags] <name> <path> [args...] -- if provided, args are passed as arguments to the runtime ` } // SetFlags implements subcommands.Command.SetFlags. func (*runtimeAdd) SetFlags(*flag.FlagSet) { } // Execute implements subcommands.Command.Execute. func (r *runtimeAdd) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus { if f.NArg() < 2 { f.Usage() return subcommands.ExitUsageError } name := f.Arg(0) path := f.Arg(1) runtimeArgs := f.Args()[2:] fmt.Printf("Adding runtime %q to file %q\n", name, *configFile) c, err := readConfig(*configFile) if err != nil { log.Fatalf("Error reading config file %q: %v", *configFile, err) } var rts map[string]interface{} if i, ok := c["runtimes"]; ok { rts = i.(map[string]interface{}) } else { rts = make(map[string]interface{}) c["runtimes"] = rts } rts[name] = runtime{Path: path, RuntimeArgs: runtimeArgs} if err := writeConfig(c, *configFile); err != nil { log.Fatalf("Error writing config file %q: %v", *configFile, err) } return subcommands.ExitSuccess } // runtimeRemove implements subcommands.Command. type runtimeRemove struct { } // Name implements subcommands.Command.Name. func (*runtimeRemove) Name() string { return "runtime-rm" } // Synopsis implements subcommands.Command.Synopsis. func (*runtimeRemove) Synopsis() string { return "removes a runtime from docker daemon configuration" } // Usage implements subcommands.Command.Usage. func (*runtimeRemove) Usage() string { return `runtime-rm [flags] <name> ` } // SetFlags implements subcommands.Command.SetFlags. func (*runtimeRemove) SetFlags(*flag.FlagSet) { } // Execute implements subcommands.Command.Execute. func (r *runtimeRemove) Execute(_ context.Context, f *flag.FlagSet, args ...interface{}) subcommands.ExitStatus { if f.NArg() != 1 { f.Usage() return subcommands.ExitUsageError } name := f.Arg(0) fmt.Printf("Removing runtime %q from file %q\n", name, *configFile) c, err := readConfig(*configFile) if err != nil { log.Fatalf("Error reading config file %q: %v", *configFile, err) } var rts map[string]interface{} if i, ok := c["runtimes"]; ok { rts = i.(map[string]interface{}) } else { log.Fatalf("runtime %q not found", name) } if _, ok := rts[name]; !ok { log.Fatalf("runtime %q not found", name) } delete(rts, name) if err := writeConfig(c, *configFile); err != nil { log.Fatalf("Error writing config file %q: %v", *configFile, err) } return subcommands.ExitSuccess } func readConfig(path string) (map[string]interface{}, error) { configBytes, err := ioutil.ReadFile(path) if err != nil && !os.IsNotExist(err) { return nil, err } c := make(map[string]interface{}) if len(configBytes) > 0 { if err := json.Unmarshal(configBytes, &c); err != nil { return nil, err } } return c, nil } func writeConfig(c map[string]interface{}, path string) error { b, err := json.MarshalIndent(c, "", " ") if err != nil { return err } if err := os.Rename(path, path+"~"); err != nil && !os.IsNotExist(err) { return fmt.Errorf("error renaming config file %q: %v", path, err) } if err := ioutil.WriteFile(path, b, 0644); err != nil { return fmt.Errorf("error writing config file %q: %v", path, err) } return nil }