Implement a '#/incremental-prebuild/' manual prefix

components/dashboard/src/start/StartWorkspace.tsx

@@ -149,7 +149,7 @@ export default class StartWorkspace extends React.Component<StartWorkspaceProps,
 
     // Successfully stopped and headless: the prebuild is done, let's try to use it!
     if (!error && workspaceInstance.status.phase === 'stopped' && this.state.workspace?.type !== 'regular') {
-      const contextUrl = this.state.workspace?.contextURL.replace('prebuild/', '')!;
+      const contextUrl = this.state.workspace?.contextURL.replace('incremental-prebuild/', '').replace('prebuild/', '')!;
       this.redirectTo(gitpodHostUrl.withContext(contextUrl).toString());
     }
 

components/server/ee/src/container-module.ts

@@ -31,6 +31,7 @@ import { GitLabApp } from "./prebuilds/gitlab-app";
 import { BitbucketApp } from "./prebuilds/bitbucket-app";
 import { IPrefixContextParser } from "../../src/workspace/context-parser";
 import { StartPrebuildContextParser } from "./prebuilds/start-prebuild-context-parser";
+import { StartIncrementalPrebuildContextParser } from "./prebuilds/start-incremental-prebuild-context-parser";
 import { WorkspaceFactory } from "../../src/workspace/workspace-factory";
 import { WorkspaceFactoryEE } from "./workspace/workspace-factory";
 import { MonitoringEndpointsAppEE } from "./monitoring-endpoint-ee";
@@ -52,6 +53,7 @@ export const productionEEContainerModule = new ContainerModule((bind, unbind, is
     bind(PrebuildRateLimiter).toSelf().inSingletonScope();
     bind(PrebuildQueueMaintainer).toSelf().inSingletonScope();
     bind(IPrefixContextParser).to(StartPrebuildContextParser).inSingletonScope();
+    bind(IPrefixContextParser).to(StartIncrementalPrebuildContextParser).inSingletonScope();
     bind(GithubApp).toSelf().inSingletonScope();
     bind(GithubAppRules).toSelf().inSingletonScope();
     bind(PrebuildStatusMaintainer).toSelf().inSingletonScope();

components/server/ee/src/prebuilds/start-incremental-prebuild-context-parser.ts

@@ -0,0 +1,42 @@
+/**
+ * Copyright (c) 2021 Gitpod GmbH. All rights reserved.
+ * Licensed under the Gitpod Enterprise Source Code License,
+ * See License.enterprise.txt in the project root folder.
+ */
+
+import { User, WorkspaceContext, StartPrebuildContext, CommitContext } from "@gitpod/gitpod-protocol";
+import { inject, injectable } from "inversify";
+import { URL } from "url";
+import { Env } from '../../../src/env';
+import { HostContextProvider } from "../../../src/auth/host-context-provider";
+import { IPrefixContextParser } from "../../../src/workspace/context-parser";
+
+@injectable()
+export class StartIncrementalPrebuildContextParser implements IPrefixContextParser {
+    @inject(Env) protected env: Env;
+    @inject(HostContextProvider) protected readonly hostContextProvider: HostContextProvider;
+    static PREFIX = 'incremental-prebuild/';
+
+    findPrefix(user: User, context: string): string | undefined {
+        if (context.startsWith(StartIncrementalPrebuildContextParser.PREFIX)) {
+            return StartIncrementalPrebuildContextParser.PREFIX;
+        }
+    }
+
+    public async handle(user: User, prefix: string, context: WorkspaceContext): Promise<WorkspaceContext> {
+        if (!CommitContext.is(context)) {
+            throw new Error("can only start incremental prebuilds on a commit context")
+        }
+
+        const host = new URL(context.repository.cloneUrl).hostname;
+        const hostContext = this.hostContextProvider.get(host);
+        const maxDepth = this.env.incrementalPrebuildsCommitHistory;
+        const result: StartPrebuildContext = {
+            title: `Prebuild of "${context.title}"`,
+            actual: context,
+            commitHistory: await (hostContext?.contextParser?.fetchCommitHistory({}, user, context.repository.cloneUrl, context.revision, maxDepth) || [])
+        };
+        return result;
+    }
+
+}