Merge pull request #112 from depot/cni

Only write CNI file if it doesn't exist

src/tasks/buildkit.ts

@@ -3,6 +3,7 @@ import {execa} from 'execa'
 import * as fsp from 'fs/promises'
 import {onShutdown, onShutdownError} from 'node-graceful-shutdown'
 import {RegisterMachineResponse, RegisterMachineResponse_BuildKitTask} from '../gen/ts/depot/cloud/v3/machine_pb'
+import {pathExists} from '../utils/common'
 import {ensureMounted, fstrim, mountExecutor, unmapBlockDevice, unmountDevice} from '../utils/mounts'
 import {reportHealth} from './health'
 import {reportUsage} from './usage'
@@ -102,7 +103,7 @@ keepBytes = ${cacheSizeBytes}
 `
   await fsp.writeFile('/etc/buildkit/buildkitd.toml', config, {mode: 0o644})
 
-  if (task.enableCni) {
+  if (task.enableCni && !(await pathExists('/etc/buildkit/cni.json'))) {
     const cniConfig = {
       cniVersion: '1.0.0',
       name: 'buildkit',

src/utils/common.ts

@@ -1,3 +1,5 @@
+import * as fsp from 'node:fs/promises'
+
 export async function promises<T extends Record<string, any>>(promises: T): Promise<{[K in keyof T]: Awaited<T[K]>}> {
   const entries = Object.entries(promises)
   const values = await Promise.all(
@@ -11,3 +13,12 @@ export const sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve
 export function assertNever(x: never): never {
   throw new Error('Unexpected value: ' + x)
 }
+
+export async function pathExists(path: string) {
+  try {
+    await fsp.access(path)
+    return true
+  } catch {
+    return false
+  }
+}