fix(amazonq): Reduce plugin start-up latency

Author: tsmithsz

packages/amazonq/src/extension.ts

@@ -3,7 +3,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { Auth, AuthUtils, CredentialsStore, LoginManager, initializeAuth } from 'aws-core-vscode/auth'
+import { AuthUtils, CredentialsStore, LoginManager, initializeAuth } from 'aws-core-vscode/auth'
 import { activate as activateCodeWhisperer, shutdown as shutdownCodeWhisperer } from 'aws-core-vscode/codewhisperer'
 import { makeEndpointsProvider, registerGenericCommands } from 'aws-core-vscode'
 import { CommonAuthWebview } from 'aws-core-vscode/login'
@@ -44,7 +44,6 @@ import * as vscode from 'vscode'
 import { registerCommands } from './commands'
 import { focusAmazonQPanel } from 'aws-core-vscode/codewhispererChat'
 import { activate as activateAmazonqLsp } from './lsp/activation'
-import { activate as activateInlineCompletion } from './app/inline/activation'
 import { hasGlibcPatch } from './lsp/client'
 
 export const amazonQContextPrefix = 'amazonq'
@@ -126,17 +125,11 @@ export async function activateAmazonQCommon(context: vscode.ExtensionContext, is
 
     // This contains every lsp agnostic things (auth, security scan, code scan)
     await activateCodeWhisperer(extContext as ExtContext)
-    if (
-        (Experiments.instance.get('amazonqLSP', true) || Auth.instance.isInternalAmazonUser()) &&
-        (!isAmazonLinux2() || hasGlibcPatch())
-    ) {
-        // start the Amazon Q LSP for internal users first
-        // for AL2, start LSP if glibc patch is found
+
+    if (!isAmazonLinux2() || hasGlibcPatch()) {
+        // Activate Amazon Q LSP for everyone unless they're using AL2 without the glibc patch
         await activateAmazonqLsp(context)
     }
-    if (!Experiments.instance.get('amazonqLSPInline', true)) {
-        await activateInlineCompletion()
-    }
 
     // Generic extension commands
     registerGenericCommands(context, amazonQContextPrefix)

packages/core/src/codewhisperer/commands/basicCommands.ts

@@ -634,6 +634,12 @@ const registerToolkitApiCallbackOnce = once(() => {
 export const registerToolkitApiCallback = Commands.declare(
     { id: 'aws.amazonq.refreshConnectionCallback' },
     () => async (toolkitApi?: any) => {
+        // Early return if already registered to avoid duplicate work
+        if (_toolkitApi) {
+            getLogger().debug('Toolkit API callback already registered, skipping')
+            return
+        }
+
         // While the Q/CW exposes an API for the Toolkit to register callbacks on auth changes,
         // we need to do it manually here because the Toolkit would have been unable to call
         // this API if the Q/CW extension started afterwards (and this code block is running).

packages/core/src/codewhisperer/region/regionProfileManager.ts

@@ -77,7 +77,7 @@ export class RegionProfileManager {
                         result: undefined,
                     },
                 },
-                { timeout: 15000, interval: 1500, truthy: true }
+                { timeout: 15000, interval: 500, truthy: true }
             )
         }
 

packages/core/src/shared/featureConfig.ts

@@ -55,6 +55,9 @@ export const featureDefinitions = new Map<FeatureName, FeatureContext>([
 
 export class FeatureConfigProvider {
     private featureConfigs = new Map<string, FeatureContext>()
+    private fetchPromise: Promise<void> | undefined = undefined
+    private lastFetchTime = 0
+    private readonly minFetchInterval = 5000 // 5 seconds minimum between fetches
 
     static #instance: FeatureConfigProvider
 
@@ -123,6 +126,28 @@ export class FeatureConfigProvider {
             return
         }
 
+        // Debounce multiple concurrent calls
+        const now = performance.now()
+        if (this.fetchPromise && now - this.lastFetchTime < this.minFetchInterval) {
+            getLogger().debug('amazonq: Debouncing feature config fetch')
+            return this.fetchPromise
+        }
+
+        if (this.fetchPromise) {
+            return this.fetchPromise
+        }
+
+        this.lastFetchTime = now
+        this.fetchPromise = this._fetchFeatureConfigsInternal()
+
+        try {
+            await this.fetchPromise
+        } finally {
+            this.fetchPromise = undefined
+        }
+    }
+
+    private async _fetchFeatureConfigsInternal(): Promise<void> {
         getLogger().debug('amazonq: Fetching feature configs')
         try {
             const response = await this.listFeatureEvaluations()

packages/core/src/shared/utilities/resourceCache.ts

@@ -60,6 +60,21 @@ export abstract class CachedResource<V> {
     abstract resourceProvider(): Promise<V>
 
     async getResource(): Promise<V> {
+        // Check cache without locking first
+        const quickCheck = this.readCacheOrDefault()
+        if (quickCheck.resource.result && !quickCheck.resource.locked) {
+            const duration = now() - quickCheck.resource.timestamp
+            if (duration < this.expirationInMilli) {
+                logger.debug(
+                    `cache hit (fast path), duration(%sms) is less than expiration(%sms), returning cached value: %s`,
+                    duration,
+                    this.expirationInMilli,
+                    this.key
+                )
+                return quickCheck.resource.result
+            }
+        }
+
         const cachedValue = await this.tryLoadResourceAndLock()
         const resource = cachedValue?.resource