feat: Add Overlaybd API server configuration and notification handling

Author: pakkah

docs/BUILDING.md

@@ -37,7 +37,12 @@ sudo mkdir /etc/overlaybd-snapshotter
 sudo cat <<-EOF | sudo tee /etc/overlaybd-snapshotter/config.json
 {
     "root": "/var/lib/overlaybd/",
-    "address": "/run/overlaybd-snapshotter/overlaybd.sock"
+    "address": "/run/overlaybd-snapshotter/overlaybd.sock",
+    "experimental": {
+        "enabled": false,
+        "preAuth": true,
+        "overlaybdApiServer": "http://127.0.0.1:9862"
+    }
 }
 EOF
 ```

docs/DOCKER.md

@@ -31,7 +31,12 @@ Edit `/etc/overlaybd-snapshotter/config.json`:
     "verbose": "info",
     "logReportCaller": false,
     "autoRemoveDev": true,
-    "mirrorRegistry": []
+    "mirrorRegistry": [],
+    "experimental": {
+        "enabled": false,
+        "preAuth": true,
+        "overlaybdApiServer": "http://127.0.0.1:9862"
+    }
 }
 ```
 

docs/QUICKSTART.md

@@ -78,7 +78,12 @@ The config file is `/etc/overlaybd-snapshotter/config.json`. Please create the f
             "host": "registry-1.docker.io",
             "insecure": false
         }
-    ]
+    ],
+    "experimental": {
+        "enabled": false,
+        "preAuth": true,
+        "overlaybdApiServer": "http://127.0.0.1:9862"
+    }
 }
 ```
 | Field | Description |
@@ -93,6 +98,9 @@ The config file is `/etc/overlaybd-snapshotter/config.json`. Please create the f
 | `exporterConfig.enable` | whether or not create a server to show Prometheus metrics |
 | `exporterConfig.uriPrefix` | URI prefix for export metrics, default `/metrics` |
 | `exporterConfig.port` | port for http server to show metrics, default `9863` |
+| `experimental.enabled` | enable experimental features |
+| `experimental.preAuth` | enable overlaybd API server pre-auth notification |
+| `experimental.overlaybdApiServer` | overlaybd API server address, default `http://127.0.0.1:9862` |
 | `mirrorRegistry` | an arrary of mirror registries |
 | `mirrorRegistry.host` | host address, eg. `registry-1.docker.io`` |
 | `mirrorRegistry.insecure` | `true` or `false` |

pkg/snapshot/docker.go

@@ -85,6 +85,8 @@ func (o *snapshotter) prepareDockerInitLayer(ctx context.Context, s storage.Snap
 			}
 		}
 
+		o.notifyOverlaybdAPIServer(o.overlaybdConfPath(parentID))
+
 		// Attach and mount overlaybd device at parent's mountpoint (readonly)
 		if err := o.attachAndMountBlockDevice(ctx, parentID, RoDir, fsType, false); err != nil {
 			return nil, fmt.Errorf("failed to attach overlaybd for docker init layer: %w", err)

pkg/snapshot/overlay.go

@@ -22,6 +22,9 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"io"
+	"net/http"
+	"net/url"
 	"os"
 	"os/exec"
 	"path"
@@ -86,6 +89,12 @@ type Registry struct {
 	Insecure bool   `json:"insecure"`
 }
 
+type ExperimentalConfig struct {
+	Enabled            bool   `json:"enabled"`
+	PreAuth            bool   `json:"preAuth"`
+	OverlaybdApiServer string `json:"overlaybdApiServer"`
+}
+
 type BootConfig struct {
 	AsyncRemove       bool                   `json:"asyncRemove"`
 	Address           string                 `json:"address"`
@@ -102,6 +111,7 @@ type BootConfig struct {
 	Tenant            int                    `json:"tenant"`      // do not set this if only a single snapshotter service in the host
 	TurboFsType       []string               `json:"turboFsType"`
 	RuntimeType       string                 `json:"runtimeType"` // "containerd" (default) or "docker"
+	Experimental      ExperimentalConfig     `json:"experimental"`
 }
 
 func DefaultBootConfig() *BootConfig {
@@ -126,6 +136,11 @@ func DefaultBootConfig() *BootConfig {
 			"ext4",
 		},
 		RuntimeType: "containerd",
+		Experimental: ExperimentalConfig{
+			Enabled:            false,
+			PreAuth:            true,
+			OverlaybdApiServer: "http://127.0.0.1:9862",
+		},
 	}
 }
 
@@ -206,6 +221,7 @@ type snapshotter struct {
 	turboFsType       []string
 	asyncRemove       bool
 	runtimeType       string
+	experimental      ExperimentalConfig
 
 	quotaDriver *diskquota.PrjQuotaDriver
 	quotaSize   string
@@ -270,6 +286,7 @@ func NewSnapshotter(bootConfig *BootConfig, opts ...Opt) (snapshots.Snapshotter,
 		turboFsType:       bootConfig.TurboFsType,
 		tenant:            bootConfig.Tenant,
 		quotaSize:         bootConfig.RootfsQuota,
+		experimental:      bootConfig.Experimental,
 		quotaDriver: &diskquota.PrjQuotaDriver{
 			QuotaIDs: make(map[uint32]struct{}),
 		},
@@ -434,6 +451,61 @@ func (o *snapshotter) lockSnapshotID(id string) func() {
 	}
 }
 
+func (o *snapshotter) preAuthEnabled() bool {
+	return o.experimental.Enabled && o.experimental.PreAuth
+}
+
+func (o *snapshotter) notifyOverlaybdAPIServer(configPath string) {
+	if !o.preAuthEnabled() || configPath == "" {
+		return
+	}
+
+	go func() {
+		address := strings.TrimSpace(o.experimental.OverlaybdApiServer)
+		if address == "" {
+			log.L.Warn("overlaybd api server address is empty")
+			return
+		}
+
+		authBase, err := url.Parse(address)
+		if err != nil {
+			log.L.WithError(err).Warnf("failed to parse overlaybd api server address %q", address)
+			return
+		}
+
+		authURL := authBase.ResolveReference(&url.URL{Path: "/auth"})
+		query := authURL.Query()
+		query.Set("config", configPath)
+		authURL.RawQuery = query.Encode()
+
+		log.L.Infof("overlaybd api request: %s", authURL.String())
+
+		reqCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		defer cancel()
+
+		req, err := http.NewRequestWithContext(reqCtx, http.MethodGet, authURL.String(), nil)
+		if err != nil {
+			log.L.WithError(err).Warnf("failed to create overlaybd api request for %s", authURL.String())
+			return
+		}
+
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			log.L.WithError(err).Warnf("overlaybd api request failed: %s", authURL.String())
+			return
+		}
+		defer resp.Body.Close()
+
+		body, err := io.ReadAll(resp.Body)
+		if err != nil {
+			log.L.WithError(err).Warnf("failed to read overlaybd api response from %s", authURL.String())
+			return
+		}
+
+		log.L.Infof("overlaybd api response: url=%s status=%s body=%s", authURL.String(), resp.Status, strings.TrimSpace(string(body)))
+	}()
+}
+
 func (o *snapshotter) cleanupFailedPrepare(ctx context.Context, key, id string) {
 	// TODO: recover half-done prepare state after process crash. This path only
 	// cleans up failures observed in-process after metadata has been committed.
@@ -757,6 +829,7 @@ func (o *snapshotter) createMountPoint(ctx context.Context, kind snapshots.Kind,
 				// concurrent Prepare/Mounts/Remove operating on the same parent snapshot.
 				unlockObd = o.lockSnapshotID(obdID)
 			}
+			o.notifyOverlaybdAPIServer(o.overlaybdConfPath(obdID))
 			if err = o.attachAndMountBlockDevice(ctx, obdID, writeType, fsType, parent == ""); err != nil {
 				unlockObd()
 				log.G(ctx).Errorf("%v", err)

pkg/snapshot/overlay_test.go

@@ -38,6 +38,62 @@ func newSnapshotterWithOpts(opts ...Opt) testsuite.SnapshotterFunc {
 	}
 }
 
+func TestDefaultBootConfigExperimental(t *testing.T) {
+	cfg := DefaultBootConfig()
+
+	if cfg.Experimental.Enabled {
+		t.Fatal("expected experimental to be disabled by default")
+	}
+	if !cfg.Experimental.PreAuth {
+		t.Fatal("expected preAuth to be enabled by default")
+	}
+	if cfg.Experimental.OverlaybdApiServer != "http://127.0.0.1:9862" {
+		t.Fatalf("unexpected overlaybd api server address %q", cfg.Experimental.OverlaybdApiServer)
+	}
+}
+
+func TestPreAuthEnabled(t *testing.T) {
+	tests := []struct {
+		name         string
+		experimental ExperimentalConfig
+		want         bool
+	}{
+		{
+			name: "experimental disabled",
+			experimental: ExperimentalConfig{
+				Enabled: false,
+				PreAuth: true,
+			},
+			want: false,
+		},
+		{
+			name: "preAuth disabled",
+			experimental: ExperimentalConfig{
+				Enabled: true,
+				PreAuth: false,
+			},
+			want: false,
+		},
+		{
+			name: "experimental and preAuth enabled",
+			experimental: ExperimentalConfig{
+				Enabled: true,
+				PreAuth: true,
+			},
+			want: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sn := &snapshotter{experimental: tt.experimental}
+			if got := sn.preAuthEnabled(); got != tt.want {
+				t.Fatalf("preAuthEnabled() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
 func TestBasicSnapshotterOnOverlayFS(t *testing.T) {
 	testutil.RequiresRoot(t)
 	testsuite.SnapshotterSuite(t, "overlaybd-on-overlayFS", newSnapshotterWithOpts())

script/config.json

@@ -6,5 +6,10 @@
     "runtimeType": "containerd",
     "logReportCaller": false,
     "autoRemoveDev": false,
-    "mirrorRegistry": []
+    "mirrorRegistry": [],
+    "experimental": {
+        "enabled": false,
+        "preAuth": true,
+        "overlaybdApiServer": "http://127.0.0.1:9862"
+    }
 }