prevent parallel builds on the same template

Author: mbfreder

packages/core/src/shared/sam/build.ts

@@ -25,6 +25,9 @@ import {
     getSamCliPathAndVersion,
     getTerminalFromError,
     isDotnetRuntime,
+    registerTemplateBuild,
+    throwIfTemplateIsBeingBuilt,
+    unregisterTemplateBuild,
     updateRecentResponse,
 } from './utils'
 import { getConfigFileUri, validateSamBuildConfig } from './config'
@@ -207,6 +210,9 @@ export async function runBuild(arg?: TreeNode): Promise<SamBuildResult> {
         throw new CancellationError('user')
     }
 
+    throwIfTemplateIsBeingBuilt(params.template.uri.path)
+    await registerTemplateBuild(params.template.uri.path)
+
     const projectRoot = params.projectRoot
 
     const defaultFlags: string[] = ['--cached', '--parallel', '--save-params', '--use-container']
@@ -242,10 +248,13 @@ export async function runBuild(arg?: TreeNode): Promise<SamBuildResult> {
         // Run SAM build in Terminal
         await runInTerminal(buildProcess, 'build')
 
+        await unregisterTemplateBuild(params.template.uri.path)
+
         return {
             isSuccess: true,
         }
     } catch (error) {
+        await unregisterTemplateBuild(params.template.uri.path)
         throw ToolkitError.chain(error, 'Failed to build SAM template', {
             details: { terminal: getTerminalFromError(error), ...resolveBuildArgConflict(buildFlags) },
             code: getErrorCode(error),

packages/core/src/shared/sam/utils.ts

@@ -108,6 +108,35 @@ export async function updateRecentResponse(
         getLogger().warn(`sam: unable to save response at key "${key}": %s`, err)
     }
 }
+
+const buildProcessMementoRootKey = 'samcli.build.processes'
+
+/**
+ * Returns true if there's an ongoing build process for the provided template, false otherwise
+ * @Param templatePath The path to the template.yaml file
+ */
+function isBuildInProgress(templatePath: string): boolean {
+    return getRecentResponse(buildProcessMementoRootKey, 'global', templatePath) !== undefined
+}
+
+/**
+ * Throws an error if there's a build in progress for the provided template
+ * @Param templatePath The path to the template.yaml file
+ */
+export function throwIfTemplateIsBeingBuilt(templatePath: string) {
+    if (isBuildInProgress(templatePath)) {
+        throw new ToolkitError('Build in progress', { code: 'BuildInProgress' })
+    }
+}
+
+export async function registerTemplateBuild(templatePath: string) {
+    await updateRecentResponse(buildProcessMementoRootKey, 'global', templatePath, 'true')
+}
+
+export async function unregisterTemplateBuild(templatePath: string) {
+    await updateRecentResponse(buildProcessMementoRootKey, 'global', templatePath, undefined)
+}
+
 export function getSamCliErrorMessage(stderr: string): string {
     // Split the stderr string by newline, filter out empty lines, and get the last line
     const lines = stderr