enhance: split config from server package

The github.com/containerd/containerd/services/server has a lot of
dependencies, like content, snapshots services implementation and
docker-metrics.

For the client side, it uses the config struct from server package
to start up the containerd in background. It will import a lot of
useless packages which might be conflict with existing vendor's package.

It makes integration easier with single config package.

Signed-off-by: Wei Fu <fuweid89@gmail.com>

services/server/config/config.go

@@ -14,7 +14,7 @@
    limitations under the License.
 */
 
-package server
+package config
 
 import (
 	"github.com/BurntSushi/toml"

services/server/server.go

@@ -40,6 +40,7 @@ import (
 	"github.com/containerd/containerd/metadata"
 	"github.com/containerd/containerd/pkg/dialer"
 	"github.com/containerd/containerd/plugin"
+	srvconfig "github.com/containerd/containerd/services/server/config"
 	"github.com/containerd/containerd/snapshots"
 	ssproxy "github.com/containerd/containerd/snapshots/proxy"
 	metrics "github.com/docker/go-metrics"
@@ -50,7 +51,7 @@ import (
 )
 
 // New creates and initializes a new containerd server
-func New(ctx context.Context, config *Config) (*Server, error) {
+func New(ctx context.Context, config *srvconfig.Config) (*Server, error) {
 	switch {
 	case config.Root == "":
 		return nil, errors.New("root must be specified")
@@ -149,7 +150,7 @@ func New(ctx context.Context, config *Config) (*Server, error) {
 type Server struct {
 	rpc     *grpc.Server
 	events  *exchange.Exchange
-	config  *Config
+	config  *srvconfig.Config
 	plugins []*plugin.Plugin
 }
 
@@ -211,7 +212,7 @@ func (s *Server) Stop() {
 
 // LoadPlugins loads all plugins into containerd and generates an ordered graph
 // of all plugins.
-func LoadPlugins(ctx context.Context, config *Config) ([]*plugin.Registration, error) {
+func LoadPlugins(ctx context.Context, config *srvconfig.Config) ([]*plugin.Registration, error) {
 	// load all plugins into containerd
 	if err := plugin.Load(filepath.Join(config.Root, "plugins")); err != nil {
 		return nil, err

services/server/server_linux.go

@@ -22,12 +22,13 @@ import (
 
 	"github.com/containerd/cgroups"
 	"github.com/containerd/containerd/log"
+	srvconfig "github.com/containerd/containerd/services/server/config"
 	"github.com/containerd/containerd/sys"
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 )
 
 // apply sets config settings on the server process
-func apply(ctx context.Context, config *Config) error {
+func apply(ctx context.Context, config *srvconfig.Config) error {
 	if config.OOMScore != 0 {
 		log.G(ctx).Debugf("changing OOM score to %d", config.OOMScore)
 		if err := sys.SetOOMScore(os.Getpid(), config.OOMScore); err != nil {

services/server/server_solaris.go

@@ -16,8 +16,12 @@
 
 package server
 
-import "context"
+import (
+	"context"
 
-func apply(_ context.Context, _ *Config) error {
+	srvconfig "github.com/containerd/containerd/server/config"
+)
+
+func apply(_ context.Context, _ *srvconfig.Config) error {
 	return nil
 }

services/server/server_test.go

@@ -20,13 +20,14 @@ import (
 	"context"
 	"testing"
 
+	srvconfig "github.com/containerd/containerd/services/server/config"
 	"gotest.tools/assert"
 	is "gotest.tools/assert/cmp"
 )
 
 func TestNewErrorsWithSamePathForRootAndState(t *testing.T) {
 	path := "/tmp/path/for/testing"
-	_, err := New(context.Background(), &Config{
+	_, err := New(context.Background(), &srvconfig.Config{
 		Root:  path,
 		State: path,
 	})

services/server/server_unsupported.go

@@ -18,8 +18,12 @@
 
 package server
 
-import "context"
+import (
+	"context"
 
-func apply(_ context.Context, _ *Config) error {
+	srvconfig "github.com/containerd/containerd/services/server/config"
+)
+
+func apply(_ context.Context, _ *srvconfig.Config) error {
 	return nil
 }

services/server/server_windows.go

@@ -20,8 +20,10 @@ package server
 
 import (
 	"context"
+
+	srvconfig "github.com/containerd/containerd/services/server/config"
 )
 
-func apply(_ context.Context, _ *Config) error {
+func apply(_ context.Context, _ *srvconfig.Config) error {
 	return nil
 }