Merge pull request #1156 from balena-io/1072-v2-v3-delta-fixes

fix: ⬇️ Force a regular pull when moving from v2 to v3 deltas

package-lock.json

@@ -256,9 +256,9 @@
       "dev": true
     },
     "@types/dockerode": {
-      "version": "2.5.20",
-      "resolved": "https://registry.npmjs.org/@types/dockerode/-/dockerode-2.5.20.tgz",
-      "integrity": "sha512-g2eM9q+pur7iZc897K/OSq8sCL7VdVcCPzNkdeTukUokfvgl3TaP+nT7G8BMpnSSojrJFKl7VdTciP7hbVgfKA==",
+      "version": "2.5.21",
+      "resolved": "https://registry.npmjs.org/@types/dockerode/-/dockerode-2.5.21.tgz",
+      "integrity": "sha512-Y9kVV7Umw0SAOsGVp06VGjlAiZbjALNhDIw69NeWNEqfI++7nQijzjWsepOkUjKHr5CrJWgK4v++6a+Ms0G/6A==",
       "dev": true,
       "requires": {
         "@types/node": "*"

package.json

@@ -42,7 +42,7 @@
     "@types/chai": "^4.1.7",
     "@types/chai-as-promised": "^7.1.2",
     "@types/common-tags": "^1.8.0",
-    "@types/dockerode": "^2.5.20",
+    "@types/dockerode": "^2.5.21",
     "@types/event-stream": "^3.3.34",
     "@types/express": "^4.11.1",
     "@types/knex": "^0.14.14",

src/lib/docker-utils.ts

@@ -89,6 +89,20 @@ export class DockerUtils extends DockerToolbelt {
 			return await this.fetchImageWithProgress(imgDest, deltaOpts, onProgress);
 		}
 
+		// We need to make sure that we're not trying to apply a
+		// v3 delta on top of a v2 delta, as this will cause the
+		// update to fail, and we must fall back to a standard
+		// image pull
+		if (
+			deltaOpts.deltaVersion === 3 &&
+			(await DockerUtils.isV2DeltaImage(this, deltaOpts.deltaSourceId))
+		) {
+			logFn(
+				`Cannot create a delta from V2 to V3, falling back to regular pull`,
+			);
+			return await this.fetchImageWithProgress(imgDest, deltaOpts, onProgress);
+		}
+
 		// Since the supevisor never calls this function with a source anymore,
 		// this should never happen, but w ehandle it anyway
 		if (deltaOpts.deltaSource == null) {
@@ -317,6 +331,19 @@ export class DockerUtils extends DockerToolbelt {
 		return (await docker.getImage(deltaImg).inspect()).Id;
 	}
 
+	public static async isV2DeltaImage(
+		docker: DockerUtils,
+		imageName: string,
+	): Promise<boolean> {
+		const inspect = await docker.getImage(imageName).inspect();
+
+		// It's extremely unlikely that an image is valid if
+		// it's smaller than 40 bytes, but a v2 delta always is.
+		// For this reason, this is the method that we use to
+		// detect when an image is a v2 delta
+		return inspect.Size < 40 && inspect.VirtualSize < 40;
+	}
+
 	private getAuthToken = memoizee(
 		async (
 			srcInfo: ImageNameParts,

test/25-deltas.spec.ts

@@ -0,0 +1,106 @@
+import { expect } from 'chai';
+import { stub } from 'sinon';
+
+import DockerUtils from '../src/lib/docker-utils';
+
+const dockerUtils = new DockerUtils({});
+
+describe('Deltas', () => {
+	it('should correctly detect a V2 delta', async () => {
+		const imageStub = stub(dockerUtils, 'getImage').returns({
+			inspect: () => {
+				return Promise.resolve({
+					Id:
+						'sha256:34ec91fe6e08cb0f867bbc069c5f499d39297eb8e874bb8ce9707537d983bcbc',
+					RepoTags: [],
+					RepoDigests: [],
+					Parent: '',
+					Comment: '',
+					Created: '2019-12-05T10:20:51.516Z',
+					Container: '',
+					ContainerConfig: {
+						Hostname: '',
+						Domainname: '',
+						User: '',
+						AttachStdin: false,
+						AttachStdout: false,
+						AttachStderr: false,
+						Tty: false,
+						OpenStdin: false,
+						StdinOnce: false,
+						Env: null,
+						Cmd: null,
+						Image: '',
+						Volumes: null,
+						WorkingDir: '',
+						Entrypoint: null,
+						OnBuild: null,
+						Labels: null,
+					},
+					DockerVersion: '',
+					Author: '',
+					Config: {
+						Hostname: '7675a23f4fdc',
+						Domainname: '',
+						User: '',
+						AttachStdin: false,
+						AttachStdout: false,
+						AttachStderr: false,
+						Tty: false,
+						OpenStdin: false,
+						StdinOnce: false,
+						Env: [
+							'PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin',
+							'TINI_VERSION=0.14.0',
+							'LC_ALL=C.UTF-8',
+							'DEBIAN_FRONTEND=noninteractive',
+							'UDEV=on',
+							'container=docker',
+							'test=123',
+						],
+						Cmd: [
+							'/bin/sh',
+							'-c',
+							"while true; do echo 'hello'; sleep 10; done;",
+						],
+						ArgsEscaped: true,
+						Image:
+							'sha256:b24946093df7157727b20934d11a7287359d8de42d8a80030f51f46a73d645ec',
+						Volumes: {
+							'/sys/fs/cgroup': {},
+						},
+						WorkingDir: '',
+						Entrypoint: ['/usr/bin/entry.sh'],
+						OnBuild: [],
+						Labels: {
+							'io.resin.architecture': 'amd64',
+							'io.resin.device-type': 'intel-nuc',
+						},
+						StopSignal: '37',
+					},
+					Architecture: '',
+					Os: 'linux',
+					Size: 17,
+					VirtualSize: 17,
+					GraphDriver: {
+						Data: null,
+						Name: 'aufs',
+					},
+					RootFS: {
+						Type: 'layers',
+						Layers: [
+							'sha256:c6e6cd4f95ef00e62f5c9df5798393470c991ca0148cb1e434b28101ed4219d3',
+						],
+					},
+					Metadata: {
+						LastTagTime: '0001-01-01T00:00:00Z',
+					},
+				});
+			},
+		} as any);
+
+		expect(await DockerUtils.isV2DeltaImage(dockerUtils, 'test')).to.be.true;
+		expect(imageStub.callCount).to.equal(1);
+		imageStub.restore();
+	});
+});