reduce background network access

Skip the UpstreamHealthProviderCheck if the window is not focused, and try again when the window becomes focused again. Some users have OS firewalls that make periodic background network access annoying for users. See https://linear.app/sourcegraph/issue/CODY-3745/codys-background-periodic-network-access-causes-2fa.

This check is used to gather latency information to properly measure actual latency for autocomplete. As long as the user has VS Code focused for slightly more than 10 seconds, it will still gather the necessary latency information for these calculations.

Fixes https://linear.app/sourcegraph/issue/CODY-3745/codys-background-periodic-network-access-causes-2fa

vscode/src/services/UpstreamHealthProvider.ts

@@ -10,7 +10,7 @@ import {
     wrapInActiveSpan,
 } from '@sourcegraph/cody-shared'
 import { fetch } from '@sourcegraph/cody-shared'
-import type * as vscode from 'vscode'
+import * as vscode from 'vscode'
 
 // We choose an interval that gives us a reasonable aggregate without causing
 // too many requests
@@ -27,12 +27,25 @@ class UpstreamHealthProvider implements vscode.Disposable {
     private lastUpstreamLatency?: number
     private lastGatewayLatency?: number
 
+    private disposables: vscode.Disposable[] = []
+
     private config: Pick<
         ClientConfigurationWithAccessToken,
         'serverEndpoint' | 'customHeaders' | 'accessToken'
     > | null = null
     private nextTimeoutId: NodeJS.Timeout | null = null
 
+    constructor() {
+        this.disposables.push(
+            vscode.window.onDidChangeWindowState(state => {
+                if (state.focused && this.lastMeasurementSkippedBecauseNotFocused) {
+                    this.lastMeasurementSkippedBecauseNotFocused = false
+                    this.enqueue(INITIAL_PING_DELAY_MS)
+                }
+            })
+        )
+    }
+
     public getUpstreamLatency(): number | undefined {
         if (!this.config) {
             return undefined
@@ -60,12 +73,18 @@ class UpstreamHealthProvider implements vscode.Disposable {
         // Enqueue the initial ping after a config change in 10 seconds. This
         // avoids running the test while the extension is still initializing and
         // competing with many other network requests.
+        this.enqueue(INITIAL_PING_DELAY_MS)
+    }
+
+    private enqueue(delay: number): void {
         if (this.nextTimeoutId) {
             clearTimeout(this.nextTimeoutId)
         }
-        this.nextTimeoutId = setTimeout(this.measure.bind(this), INITIAL_PING_DELAY_MS)
+        this.nextTimeoutId = setTimeout(this.measure.bind(this), delay)
     }
 
+    private lastMeasurementSkippedBecauseNotFocused = false
+
     private async measure() {
         if (this.nextTimeoutId) {
             clearTimeout(this.nextTimeoutId)
@@ -76,6 +95,15 @@ class UpstreamHealthProvider implements vscode.Disposable {
                 return
             }
 
+            if (!vscode.window.state.focused) {
+                // Skip if the window is not focused, and try again when the window becomes focused
+                // again. Some users have OS firewalls that make periodic background network access
+                // annoying for users, and this eliminates that annoyance. See
+                // https://linear.app/sourcegraph/issue/CODY-3745/codys-background-periodic-network-access-causes-2fa.
+                this.lastMeasurementSkippedBecauseNotFocused = true
+                return
+            }
+
             if (!this.config) {
                 throw new Error('UpstreamHealthProvider not initialized')
             }
@@ -140,17 +168,17 @@ class UpstreamHealthProvider implements vscode.Disposable {
             // We don't care about errors here, we just want to measure the latency
         } finally {
             // Enqueue a new ping
-            if (this.nextTimeoutId) {
-                clearTimeout(this.nextTimeoutId)
-            }
-            this.nextTimeoutId = setTimeout(this.measure.bind(this), PING_INTERVAL_MS)
+            this.enqueue(PING_INTERVAL_MS)
         }
     }
 
     public dispose(): void {
         if (this.nextTimeoutId) {
             clearTimeout(this.nextTimeoutId)
         }
+        for (const disposable of this.disposables) {
+            disposable.dispose()
+        }
     }
 }