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Clean runtime create and make it simple

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Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
This commit is contained in:
Michael Crosby 2014-04-07 12:20:23 -07:00
parent c987aa09d8
commit 1277885420
1 changed files with 103 additions and 53 deletions
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156
runtime/runtime.go
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@ -371,53 +371,86 @@ func (runtime *Runtime) restore() error {
// Create creates a new container from the given configuration with a given name.
func (runtime *Runtime) Create(config *runconfig.Config, name string) (*Container, []string, error) {
// Lookup image
var (
container *Container
warnings []string
)
img, err := runtime.repositories.LookupImage(config.Image)
if err != nil {
return nil, nil, err
}
if err := runtime.checkImageDepth(img); err != nil {
return nil, nil, err
}
if warnings, err = runtime.mergeAndVerifyConfig(config, img); err != nil {
return nil, nil, err
}
if container, err = runtime.newContainer(name, config, img); err != nil {
return nil, nil, err
}
if err := runtime.createRootfs(container, img); err != nil {
return nil, nil, err
}
if err := runtime.setupContainerDns(container, config); err != nil {
return nil, nil, err
}
if err := container.ToDisk(); err != nil {
return nil, nil, err
}
if err := runtime.Register(container); err != nil {
return nil, nil, err
}
return container, warnings, nil
}
func (runtime *Runtime) checkImageDepth(img *image.Image) error {
// We add 2 layers to the depth because the container's rw and
// init layer add to the restriction
depth, err := img.Depth()
if err != nil {
return nil, nil, err
return err
}
if depth+2 >= MaxImageDepth {
return nil, nil, fmt.Errorf("Cannot create container with more than %d parents", MaxImageDepth)
return fmt.Errorf("Cannot create container with more than %d parents", MaxImageDepth)
}
return nil
}
checkDeprecatedExpose := func(config *runconfig.Config) bool {
if config != nil {
if config.PortSpecs != nil {
for _, p := range config.PortSpecs {
if strings.Contains(p, ":") {
return true
}
func (runtime *Runtime) checkDeprecatedExpose(config *runconfig.Config) bool {
if config != nil {
if config.PortSpecs != nil {
for _, p := range config.PortSpecs {
if strings.Contains(p, ":") {
return true
}
}
}
return false
}
return false
}
func (runtime *Runtime) mergeAndVerifyConfig(config *runconfig.Config, img *image.Image) ([]string, error) {
warnings := []string{}
if checkDeprecatedExpose(img.Config) || checkDeprecatedExpose(config) {
if runtime.checkDeprecatedExpose(img.Config) || runtime.checkDeprecatedExpose(config) {
warnings = append(warnings, "The mapping to public ports on your host via Dockerfile EXPOSE (host:port:port) has been deprecated. Use -p to publish the ports.")
}
if img.Config != nil {
if err := runconfig.Merge(config, img.Config); err != nil {
return nil, nil, err
return nil, err
}
}
if len(config.Entrypoint) == 0 && len(config.Cmd) == 0 {
return nil, nil, fmt.Errorf("No command specified")
return nil, fmt.Errorf("No command specified")
}
return warnings, nil
}
// Generate id
id := utils.GenerateRandomID()
func (runtime *Runtime) generateIdAndName(name string) (string, string, error) {
var (
err error
id = utils.GenerateRandomID()
)
if name == "" {
name, err = generateRandomName(runtime)
@ -426,47 +459,51 @@ func (runtime *Runtime) Create(config *runconfig.Config, name string) (*Containe
}
} else {
if !validContainerNamePattern.MatchString(name) {
return nil, nil, fmt.Errorf("Invalid container name (%s), only %s are allowed", name, validContainerNameChars)
return "", "", fmt.Errorf("Invalid container name (%s), only %s are allowed", name, validContainerNameChars)
}
}
if name[0] != '/' {
name = "/" + name
}
// Set the enitity in the graph using the default name specified
if _, err := runtime.containerGraph.Set(name, id); err != nil {
if !graphdb.IsNonUniqueNameError(err) {
return nil, nil, err
return "", "", err
}
conflictingContainer, err := runtime.GetByName(name)
if err != nil {
if strings.Contains(err.Error(), "Could not find entity") {
return nil, nil, err
return "", "", err
}
// Remove name and continue starting the container
if err := runtime.containerGraph.Delete(name); err != nil {
return nil, nil, err
return "", "", err
}
} else {
nameAsKnownByUser := strings.TrimPrefix(name, "/")
return nil, nil, fmt.Errorf(
return "", "", fmt.Errorf(
"Conflict, The name %s is already assigned to %s. You have to delete (or rename) that container to be able to assign %s to a container again.", nameAsKnownByUser,
utils.TruncateID(conflictingContainer.ID), nameAsKnownByUser)
}
}
return id, name, nil
}
func (runtime *Runtime) generateHostname(id string, config *runconfig.Config) {
// 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
func (runtime *Runtime) getEntrypointAndArgs(config *runconfig.Config) (string, []string) {
var (
entrypoint string
args []string
)
if len(config.Entrypoint) != 0 {
entrypoint = config.Entrypoint[0]
args = append(config.Entrypoint[1:], config.Cmd...)
@ -474,6 +511,21 @@ func (runtime *Runtime) Create(config *runconfig.Config, name string) (*Containe
entrypoint = config.Cmd[0]
args = config.Cmd[1:]
}
return entrypoint, args
}
func (runtime *Runtime) newContainer(name string, config *runconfig.Config, img *image.Image) (*Container, error) {
var (
id string
err error
)
id, name, err = runtime.generateIdAndName(name)
if err != nil {
return nil, err
}
runtime.generateHostname(id, config)
entrypoint, args := runtime.getEntrypointAndArgs(config)
container := &Container{
// FIXME: we should generate the ID here instead of receiving it as an argument
@ -490,42 +542,50 @@ func (runtime *Runtime) Create(config *runconfig.Config, name string) (*Containe
ExecDriver: runtime.execDriver.Name(),
}
container.root = runtime.containerRoot(container.ID)
return container, nil
}
func (runtime *Runtime) createRootfs(container *Container, img *image.Image) error {
// 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
return err
}
initID := fmt.Sprintf("%s-init", container.ID)
if err := runtime.driver.Create(initID, img.ID, ""); err != nil {
return nil, nil, err
return err
}
initPath, err := runtime.driver.Get(initID)
if err != nil {
return nil, nil, err
return err
}
defer runtime.driver.Put(initID)
if err := graph.SetupInitLayer(initPath); err != nil {
return nil, nil, err
return err
}
if err := runtime.driver.Create(container.ID, initID, ""); err != nil {
return nil, nil, err
return err
}
return nil
}
func (runtime *Runtime) setupContainerDns(container *Container, config *runconfig.Config) error {
resolvConf, err := utils.GetResolvConf()
if err != nil {
return nil, nil, err
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 {
dns := utils.GetNameservers(resolvConf)
dnsSearch := utils.GetSearchDomains(resolvConf)
var (
dns = utils.GetNameservers(resolvConf)
dnsSearch = utils.GetSearchDomains(resolvConf)
)
if len(config.Dns) > 0 {
dns = config.Dns
} else if len(runtime.config.Dns) > 0 {
@ -539,33 +599,23 @@ func (runtime *Runtime) Create(config *runconfig.Config, name string) (*Containe
container.ResolvConfPath = path.Join(container.root, "resolv.conf")
f, err := os.Create(container.ResolvConfPath)
if err != nil {
return nil, nil, err
return err
}
defer f.Close()
for _, dns := range dns {
if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
return nil, nil, err
return err
}
}
if len(dnsSearch) > 0 {
if _, err := f.Write([]byte("search " + strings.Join(dnsSearch, " ") + "\n")); err != nil {
return nil, nil, err
return 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
return nil
}
// Commit creates a new filesystem image from the current state of a container.