fix: Stop and finalize build on exec termination

src/commands/exec.ts

@@ -1,4 +1,4 @@
-import {flags} from '@oclif/command'
+import { flags } from '@oclif/command'
 import * as spawn from 'cross-spawn'
 import { DEFAULT_CONFIGURATION } from '../configuration/configuration'
 import ConfigurationService from '../services/configuration-service'
@@ -32,12 +32,13 @@ export default class Exec extends PercyCommand {
     }),
   }
 
+  // helps prevent exiting before the agent service has stopped
+  private exiting = false
+
   async run() {
     await super.run()
 
-    const {argv} = this.parse(Exec)
-    const {flags} = this.parse(Exec)
-
+    const { argv, flags } = this.parse(Exec)
     const command = argv.shift()
 
     if (!command) {
@@ -54,14 +55,23 @@ export default class Exec extends PercyCommand {
     }
 
     // Even if Percy will not run, continue to run the subprocess
-    const spawnedProcess = spawn(command, argv, {stdio: 'inherit'})
+    const spawnedProcess = spawn(command, argv, { stdio: 'inherit' })
+    spawnedProcess.on('exit', (code) => this.stop(code))
+
+    // Receiving any of these events should stop the agent and exit
+    process.on('SIGHUP', () => this.stop())
+    process.on('SIGINT', () => this.stop())
+    process.on('SIGTERM', () => this.stop())
+  }
 
-    spawnedProcess.on('exit', async (code: any) => {
-      if (this.percyWillRun()) {
-        await this.agentService.stop()
-      }
+  private async stop(exitCode?: number | null) {
+    if (this.exiting) { return }
+    this.exiting = true
+
+    if (this.percyWillRun()) {
+      await this.agentService.stop()
+    }
 
-      process.exit(code)
-    })
+    process.exit(exitCode || 0)
   }
 }

src/commands/percy-command.ts

@@ -22,7 +22,7 @@ export default class PercyCommand extends Command {
   }
 
   async run() {
-    if (this.percyEnabled && !this.percyTokenPresent()) {
+    if (this.percyEnabled() && !this.percyTokenPresent()) {
       this.warn('Skipping visual tests. PERCY_TOKEN was not provided.')
     }
   }

test/commands/percy-command.test.ts

@@ -14,15 +14,13 @@ describe('percy-command', () => {
     .stub(process, 'env', {PERCY_ENABLE: '0', PERCY_TOKEN: ''})
     .stderr()
     .command(['percy-command'])
-    .do((output) => expect(output.stderr).to.contain(
-      'Warning: Skipping visual tests. PERCY_TOKEN was not provided.',
-    ))
-    .it('warns about PERCY_TOKEN to be set')
+    .do((output) => expect(output.stderr).to.eql(''))
+    .it('outputs no warnings when PERCY_ENABLED is 0')
 
   test
-    .stub(process, 'env', {PERCY_ENABLE: '0', PERCY_TOKEN: 'ABC'})
+    .stub(process, 'env', {PERCY_TOKEN: 'ABC'})
     .stderr()
     .command(['percy-command'])
     .do((output) => expect(output.stderr).to.eql(''))
-    .it('outputs no errors')
+    .it('outputs no errors when PERCY_TOKEN is set')
 })