Golang utils.CheckLocalDns函數代碼示例

func (daemon *Daemon) checkLocaldns() error {
	resolvConf, err := resolvconf.Get()
	if err != nil {
		return err
	}
	if len(daemon.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		log.Printf("Local (127.0.0.1) DNS resolver found in resolv.conf and containers can't use it. Using default external servers : %v\n", DefaultDns)
		daemon.config.Dns = DefaultDns
	}
	return nil
}

func (runtime *Runtime) checkLocaldns() error {
	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return err
	}
	if len(runtime.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		log.Printf("Local (127.0.0.1) DNS resolver found in resolv.conf and containers can't use it. Using default external servers : %v\n", DefaultDns)
		runtime.config.Dns = DefaultDns
	}
	return nil
}

func postContainersCreate(srv *Server, version float64, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	config := &Config{}
	out := &APIRun{}

	if err := json.NewDecoder(r.Body).Decode(config); err != nil {
		return err
	}

	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return err
	}

	if len(config.Dns) == 0 && len(srv.runtime.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		out.Warnings = append(out.Warnings, fmt.Sprintf("Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns))
		config.Dns = defaultDns
	}

	id, err := srv.ContainerCreate(config)
	if err != nil {
		return err
	}
	out.ID = id

	if config.Memory > 0 && !srv.runtime.capabilities.MemoryLimit {
		log.Println("WARNING: Your kernel does not support memory limit capabilities. Limitation discarded.")
		out.Warnings = append(out.Warnings, "Your kernel does not support memory limit capabilities. Limitation discarded.")
	}
	if config.Memory > 0 && !srv.runtime.capabilities.SwapLimit {
		log.Println("WARNING: Your kernel does not support swap limit capabilities. Limitation discarded.")
		out.Warnings = append(out.Warnings, "Your kernel does not support memory swap capabilities. Limitation discarded.")
	}

	if !srv.runtime.capabilities.IPv4Forwarding {
		log.Println("Warning: IPv4 forwarding is disabled.")
		out.Warnings = append(out.Warnings, "IPv4 forwarding is disabled.")
	}

	b, err := json.Marshal(out)
	if err != nil {
		return err
	}
	w.WriteHeader(http.StatusCreated)
	writeJSON(w, b)
	return nil
}

func (runtime *Runtime) setupContainerDns(container *Container, config *runconfig.Config) error {
	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return err
	}
	if len(config.Dns) == 0 && len(runtime.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		runtime.config.Dns = DefaultDns
	}

	// If custom dns exists, then create a resolv.conf for the container
	if len(config.Dns) > 0 || len(runtime.config.Dns) > 0 || len(config.DnsSearch) > 0 || len(runtime.config.DnsSearch) > 0 {
		var (
			dns       = utils.GetNameservers(resolvConf)
			dnsSearch = utils.GetSearchDomains(resolvConf)
		)
		if len(config.Dns) > 0 {
			dns = config.Dns
		} else if len(runtime.config.Dns) > 0 {
			dns = runtime.config.Dns
		}
		if len(config.DnsSearch) > 0 {
			dnsSearch = config.DnsSearch
		} else if len(runtime.config.DnsSearch) > 0 {
			dnsSearch = runtime.config.DnsSearch
		}
		container.ResolvConfPath = path.Join(container.root, "resolv.conf")
		f, err := os.Create(container.ResolvConfPath)
		if err != nil {
			return err
		}
		defer f.Close()
		for _, dns := range dns {
			if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
				return err
			}
		}
		if len(dnsSearch) > 0 {
			if _, err := f.Write([]byte("search " + strings.Join(dnsSearch, " ") + "\n")); err != nil {
				return err
			}
		}
	} else {
		container.ResolvConfPath = "/etc/resolv.conf"
	}
	return nil
}

func postContainersCreate(srv *Server, version float64, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if err := parseForm(r); err != nil {
		return nil
	}
	out := &APIRun{}
	job := srv.Eng.Job("create", r.Form.Get("name"))
	if err := job.DecodeEnv(r.Body); err != nil {
		return err
	}
	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return err
	}
	if !job.GetenvBool("NetworkDisabled") && len(job.Getenv("Dns")) == 0 && len(srv.runtime.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		out.Warnings = append(out.Warnings, fmt.Sprintf("Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns))
		job.SetenvList("Dns", defaultDns)
	}
	// Read container ID from the first line of stdout
	job.StdoutParseString(&out.ID)
	// Read warnings from stderr
	job.StderrParseLines(&out.Warnings, 0)
	if err := job.Run(); err != nil {
		return err
	}
	if job.GetenvInt("Memory") > 0 && !srv.runtime.capabilities.MemoryLimit {
		log.Println("WARNING: Your kernel does not support memory limit capabilities. Limitation discarded.")
		out.Warnings = append(out.Warnings, "Your kernel does not support memory limit capabilities. Limitation discarded.")
	}
	if job.GetenvInt("Memory") > 0 && !srv.runtime.capabilities.SwapLimit {
		log.Println("WARNING: Your kernel does not support swap limit capabilities. Limitation discarded.")
		out.Warnings = append(out.Warnings, "Your kernel does not support memory swap capabilities. Limitation discarded.")
	}

	if !job.GetenvBool("NetworkDisabled") && srv.runtime.capabilities.IPv4ForwardingDisabled {
		log.Println("Warning: IPv4 forwarding is disabled.")
		out.Warnings = append(out.Warnings, "IPv4 forwarding is disabled.")
	}

	return writeJSON(w, http.StatusCreated, out)
}

//.........這裏部分代碼省略.........
	var args []string
	var entrypoint string

	if len(config.Entrypoint) != 0 {
		entrypoint = config.Entrypoint[0]
		args = append(config.Entrypoint[1:], config.Cmd...)
	} else {
		entrypoint = config.Cmd[0]
		args = config.Cmd[1:]
	}

	container := &Container{
		// FIXME: we should generate the ID here instead of receiving it as an argument
		ID:              id,
		Created:         time.Now(),
		Path:            entrypoint,
		Args:            args, //FIXME: de-duplicate from config
		Config:          config,
		Image:           img.ID, // Always use the resolved image id
		NetworkSettings: &NetworkSettings{},
		// FIXME: do we need to store this in the container?
		SysInitPath: sysInitPath,
		Name:        name,
	}
	container.root = runtime.containerRoot(container.ID)
	// Step 1: create the container directory.
	// This doubles as a barrier to avoid race conditions.
	if err := os.Mkdir(container.root, 0700); err != nil {
		return nil, nil, err
	}

	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return nil, nil, err
	}

	if len(config.Dns) == 0 && len(runtime.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		//"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns
		runtime.config.Dns = defaultDns
	}

	// If custom dns exists, then create a resolv.conf for the container
	if len(config.Dns) > 0 || len(runtime.config.Dns) > 0 {
		var dns []string
		if len(config.Dns) > 0 {
			dns = config.Dns
		} else {
			dns = runtime.config.Dns
		}
		container.ResolvConfPath = path.Join(container.root, "resolv.conf")
		f, err := os.Create(container.ResolvConfPath)
		if err != nil {
			return nil, nil, err
		}
		defer f.Close()
		for _, dns := range dns {
			if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
				return nil, nil, err
			}
		}
	} else {
		container.ResolvConfPath = "/etc/resolv.conf"
	}

	// Step 2: save the container json
	if err := container.ToDisk(); err != nil {
		return nil, nil, err
	}

	// Step 3: if hostname, build hostname and hosts files
	container.HostnamePath = path.Join(container.root, "hostname")
	ioutil.WriteFile(container.HostnamePath, []byte(container.Config.Hostname+"\n"), 0644)

	hostsContent := []byte(`
127.0.0.1	localhost
::1		localhost ip6-localhost ip6-loopback
fe00::0		ip6-localnet
ff00::0		ip6-mcastprefix
ff02::1		ip6-allnodes
ff02::2		ip6-allrouters
`)

	container.HostsPath = path.Join(container.root, "hosts")

	if container.Config.Domainname != "" {
		hostsContent = append([]byte(fmt.Sprintf("::1\t\t%s.%s %s\n", container.Config.Hostname, container.Config.Domainname, container.Config.Hostname)), hostsContent...)
		hostsContent = append([]byte(fmt.Sprintf("127.0.0.1\t%s.%s %s\n", container.Config.Hostname, container.Config.Domainname, container.Config.Hostname)), hostsContent...)
	} else {
		hostsContent = append([]byte(fmt.Sprintf("::1\t\t%s\n", container.Config.Hostname)), hostsContent...)
		hostsContent = append([]byte(fmt.Sprintf("127.0.0.1\t%s\n", container.Config.Hostname)), hostsContent...)
	}

	ioutil.WriteFile(container.HostsPath, hostsContent, 0644)

	// Step 4: register the container
	if err := runtime.Register(container); err != nil {
		return nil, nil, err
	}
	return container, warnings, nil
}

//.........這裏部分代碼省略.........

	// Generate default hostname
	// FIXME: the lxc template no longer needs to set a default hostname
	if config.Hostname == "" {
		config.Hostname = id[:12]
	}

	var args []string
	var entrypoint string

	if len(config.Entrypoint) != 0 {
		entrypoint = config.Entrypoint[0]
		args = append(config.Entrypoint[1:], config.Cmd...)
	} else {
		entrypoint = config.Cmd[0]
		args = config.Cmd[1:]
	}

	container := &Container{
		// FIXME: we should generate the ID here instead of receiving it as an argument
		ID:              id,
		Created:         time.Now().UTC(),
		Path:            entrypoint,
		Args:            args, //FIXME: de-duplicate from config
		Config:          config,
		hostConfig:      &runconfig.HostConfig{},
		Image:           img.ID, // Always use the resolved image id
		NetworkSettings: &NetworkSettings{},
		Name:            name,
		Driver:          runtime.driver.String(),
		ExecDriver:      runtime.execDriver.Name(),
	}
	container.root = runtime.containerRoot(container.ID)
	// Step 1: create the container directory.
	// This doubles as a barrier to avoid race conditions.
	if err := os.Mkdir(container.root, 0700); err != nil {
		return nil, nil, err
	}

	initID := fmt.Sprintf("%s-init", container.ID)
	if err := runtime.driver.Create(initID, img.ID); err != nil {
		return nil, nil, err
	}
	initPath, err := runtime.driver.Get(initID)
	if err != nil {
		return nil, nil, err
	}
	defer runtime.driver.Put(initID)

	if err := setupInitLayer(initPath); err != nil {
		return nil, nil, err
	}

	if err := runtime.driver.Create(container.ID, initID); err != nil {
		return nil, nil, err
	}
	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return nil, nil, err
	}

	if len(config.Dns) == 0 && len(runtime.config.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		//"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns
		runtime.config.Dns = defaultDns
	}

	// If custom dns exists, then create a resolv.conf for the container
	if len(config.Dns) > 0 || len(runtime.config.Dns) > 0 {
		var dns []string
		if len(config.Dns) > 0 {
			dns = config.Dns
		} else {
			dns = runtime.config.Dns
		}
		container.ResolvConfPath = path.Join(container.root, "resolv.conf")
		f, err := os.Create(container.ResolvConfPath)
		if err != nil {
			return nil, nil, err
		}
		defer f.Close()
		for _, dns := range dns {
			if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
				return nil, nil, err
			}
		}
	} else {
		container.ResolvConfPath = "/etc/resolv.conf"
	}

	// Step 2: save the container json
	if err := container.ToDisk(); err != nil {
		return nil, nil, err
	}

	// Step 3: register the container
	if err := runtime.Register(container); err != nil {
		return nil, nil, err
	}
	return container, warnings, nil
}

// Create creates a new container from the given configuration.
func (runtime *Runtime) Create(config *Config) (*Container, error) {
	// Lookup image
	img, err := runtime.repositories.LookupImage(config.Image)
	if err != nil {
		return nil, err
	}

	if img.Config != nil {
		MergeConfig(config, img.Config)
	}

	if len(config.Entrypoint) != 0 && config.Cmd == nil {
		config.Cmd = []string{}
	} else if config.Cmd == nil || len(config.Cmd) == 0 {
		return nil, fmt.Errorf("No command specified")
	}

	// Generate id
	id := GenerateID()
	// Generate default hostname
	// FIXME: the lxc template no longer needs to set a default hostname
	if config.Hostname == "" {
		config.Hostname = id[:12]
	}

	var args []string
	var entrypoint string

	if len(config.Entrypoint) != 0 {
		entrypoint = config.Entrypoint[0]
		args = append(config.Entrypoint[1:], config.Cmd...)
	} else {
		entrypoint = config.Cmd[0]
		args = config.Cmd[1:]
	}

	container := &Container{
		// FIXME: we should generate the ID here instead of receiving it as an argument
		ID:              id,
		Created:         time.Now(),
		Path:            entrypoint,
		Args:            args, //FIXME: de-duplicate from config
		Config:          config,
		Image:           img.ID, // Always use the resolved image id
		NetworkSettings: &NetworkSettings{},
		// FIXME: do we need to store this in the container?
		SysInitPath: sysInitPath,
	}
	container.root = runtime.containerRoot(container.ID)
	// Step 1: create the container directory.
	// This doubles as a barrier to avoid race conditions.
	if err := os.Mkdir(container.root, 0700); err != nil {
		return nil, err
	}

	resolvConf, err := utils.GetResolvConf()
	if err != nil {
		return nil, err
	}

	if len(config.Dns) == 0 && len(runtime.Dns) == 0 && utils.CheckLocalDns(resolvConf) {
		//"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns
		runtime.Dns = defaultDns
	}

	// If custom dns exists, then create a resolv.conf for the container
	if len(config.Dns) > 0 || len(runtime.Dns) > 0 {
		var dns []string
		if len(config.Dns) > 0 {
			dns = config.Dns
		} else {
			dns = runtime.Dns
		}
		container.ResolvConfPath = path.Join(container.root, "resolv.conf")
		f, err := os.Create(container.ResolvConfPath)
		if err != nil {
			return nil, err
		}
		defer f.Close()
		for _, dns := range dns {
			if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
				return nil, err
			}
		}
	} else {
		container.ResolvConfPath = "/etc/resolv.conf"
	}

	// Step 2: save the container json
	if err := container.ToDisk(); err != nil {
		return nil, err
	}

	// Step 3: if hostname, build hostname and hosts files
	container.HostnamePath = path.Join(container.root, "hostname")
	ioutil.WriteFile(container.HostnamePath, []byte(container.Config.Hostname+"\n"), 0644)

	hostsContent := []byte(`
127.0.0.1	localhost
//.........這裏部分代碼省略.........

func (builder *Builder) Create(config *Config) (*Container, error) {
	// Lookup image
	img, err := builder.repositories.LookupImage(config.Image)
	if err != nil {
		return nil, err
	}

	if img.Config != nil {
		MergeConfig(config, img.Config)
	}

	if config.Cmd == nil || len(config.Cmd) == 0 {
		return nil, fmt.Errorf("No command specified")
	}

	// Generate id
	id := GenerateID()
	// Generate default hostname
	// FIXME: the lxc template no longer needs to set a default hostname
	if config.Hostname == "" {
		config.Hostname = id[:12]
	}

	var args []string
	var entrypoint string

	if len(config.Entrypoint) != 0 {
		entrypoint = config.Entrypoint[0]
		args = append(config.Entrypoint[1:], config.Cmd...)
	} else {
		entrypoint = config.Cmd[0]
		args = config.Cmd[1:]
	}

	container := &Container{
		// FIXME: we should generate the ID here instead of receiving it as an argument
		ID:              id,
		Created:         time.Now(),
		Path:            entrypoint,
		Args:            args, //FIXME: de-duplicate from config
		Config:          config,
		Image:           img.ID, // Always use the resolved image id
		NetworkSettings: &NetworkSettings{},
		// FIXME: do we need to store this in the container?
		SysInitPath: sysInitPath,
	}
	container.root = builder.runtime.containerRoot(container.ID)
	// Step 1: create the container directory.
	// This doubles as a barrier to avoid race conditions.
	if err := os.Mkdir(container.root, 0700); err != nil {
		return nil, err
	}

	// create the 'rw' directory in case a container is commited without being started
	if err := os.Mkdir(path.Join(container.root, "rw"), 0755); err != nil {
		return nil, err
	}

	if len(config.Dns) == 0 && len(builder.runtime.Dns) == 0 && utils.CheckLocalDns() {
		//"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns
		builder.runtime.Dns = defaultDns
	}

	// If custom dns exists, then create a resolv.conf for the container
	if len(config.Dns) > 0 || len(builder.runtime.Dns) > 0 {
		var dns []string
		if len(config.Dns) > 0 {
			dns = config.Dns
		} else {
			dns = builder.runtime.Dns
		}
		container.ResolvConfPath = path.Join(container.root, "resolv.conf")
		f, err := os.Create(container.ResolvConfPath)
		if err != nil {
			return nil, err
		}
		defer f.Close()
		for _, dns := range dns {
			if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
				return nil, err
			}
		}
	} else {
		container.ResolvConfPath = "/etc/resolv.conf"
	}

	// Step 2: save the container json
	if err := container.ToDisk(); err != nil {
		return nil, err
	}
	// Step 3: register the container
	if err := builder.runtime.Register(container); err != nil {
		return nil, err
	}
	return container, nil
}