Amplify-cli: Failed to start API Mock endpoint Typerror

[marlonmarcello]

Describe the bug
Trying to mock the API returns an error that is untraceable and not very unhelpful.
Failed to start API Mock endpoint TypeError: Cannot read property '0' of null

Amplify CLI Version
cli version: 4.21.0
amplify version: 3.0.11

To Reproduce
mkdir amplify-bug
cd amplify-bug
amplify init
amplify add auth <= default config
amplify add api <= graphql default config

Use the following schema:

type Project
  @model
  @auth(
    rules: [
      { allow: groups, groups: ["Reg", "Admin"] }
      { allow: groups, groupsField: "client", operations: [read] }
    ]
  )
  @key(name: "ByClient", fields: ["client"], queryField: "projectsByClient")
  @key(name: "BySlug", fields: ["slug"], queryField: "projectsBySlug") {
  id: ID!
  title: String!
  slug: String!
  client: ClientGroupEnum!
  description: String
  logo: S3Object
  concepts: [Concept]
    @connection(keyName: "byConcept", fields: ["id"], sortField: "createdAt")
}

enum ClientGroupEnum {
  Reg
  Aux
  Tyt
}

type Concept
  @model(queries: null)
  @key(name: "byConcept", fields: ["projectID"])
  @auth(
    rules: [
      {
        allow: groups
        groups: ["Admin", "Reg"]
        operations: [create, update, delete]
      }
    ]
  ) {
  id: ID!
  name: String!
  projectID: ID!
  moodboard: S3Object
  pages: [Page]
    @connection(keyName: "byPage", fields: ["id"], sortField: "createdAt")
}

type Page
  @model(queries: null)
  @key(name: "byPage", fields: ["conceptID"])
  @auth(
    rules: [
      {
        allow: groups
        groups: ["Admin", "Reg"]
        operations: [create, update, delete]
      }
    ]
  ) {
  id: ID!
  name: String!
  size: PageSizeEnum!
  conceptID: ID!
  image: S3Object!
}

type S3Object {
  key: String!
  identityId: String!
}

enum PageSizeEnum {
  Small
  Medium
  Large
}

Expected behavior
Mock API endpoint working

Desktop (please complete the following information):

• OS: Mac
• Node Version: v12.16.2

[ammarkarachi]

@marlonmarcello can you share your folder .graphqlconfig.yml contents? I am having trouble reproducing the issue with the schema your provided

[marlonmarcello]

It's on a private project, can I share that through email? Maybe dropbox or something?

[ammarkarachi]

Sure you can email [email protected] make sure you mention the issue number in the subject

[marlonmarcello]

Sent. Thank you @ammarkarachi

[ammarkarachi]

@marlonmarcello I was unable to reproduce but can you check if you have the necessary permissions on '/Volumes/projects/prototypes/amp-bug' ?

[marlonmarcello]

I do also that same issue is happening on another project on a different
place on my machine.
That is strange. I tried removing and installing the cli multiple times.

On Tue, May 26, 2020 at 3:40 PM Ammar [e-mail] wrote:

@marlonmarcello https://github.com/marlonmarcello I was unable to
reproduce but can you check if you have the necessary permissions on
'/Volumes/projects/prototypes/amp-bug' ?

—
You are receiving this because you were mentioned.
Reply to this email directly, view it on GitHub
https://github.com/aws-amplify/amplify-cli/issues/4375#issuecomment-634317946,
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[sambwest]

I'm getting the same error today - version 4.21.0

[benmj]

I also experienced this when running amplify mock on 4.21.0. I had made no changes to a schema that I was working on last week. The only change was the upgrade.

I downgraded to 4.20.0 and amplify mock now successfully starts the mock service.

Environment: MacOS 10.15.4 (Catalina)
Node version: 12.16.2

[marlonmarcello]

@benmj you are right. Reverting back to 4.20.x fixes this.
What else can I do to help @ammarkarachi ?

[ammarkarachi]

@marlonmarcello
I have the mock running with the following settings with your project are these the values you are using?

GraphQL schema compiled successfully.

Edit your schema at .....amp-bug/amplify/backend/api/ampbug/schema.graphql or place .graphql files in a directory at .../amp-bug/amplify/backend/api/ampbug/schema
Creating new table ProjectTable
Creating new table ConceptTable
Creating new table PageTable
Running GraphQL codegen
? Choose the code generation language target javascript
? Enter the file name pattern of graphql queries, mutations and subscriptions src/graphql/**/*.js
? Do you want to generate/update all possible GraphQL operations - queries, mutations and subscriptions Yes
? Enter maximum statement depth [increase from default if your schema is deeply nested] 2
✔ Generated GraphQL operations successfully and saved at src/graphql
AppSync Mock endpoint is running at http://localhost:20002

[marlonmarcello]

Yes. I have the default options as well.
I tried again but with no luck. v4.21 is broken for me.

[dwamianm]

Also experiencing this in 4.21.0

Downgrading to 4.20.0 fixed the issue

Here is additional information @ammarkarachi @marlonmarcello

^X^C(node:29546) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'stop' of undefined
    at APITest. (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:82:41)
    at Generator.next ()
    at /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:8:71
    at new Promise ()
    at __awaiter (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:4:12)
    at APITest.stop (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:66:16)
    at APITest. (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:36:32)
    at Generator.next ()
    at /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:8:71
    at new Promise ()
(node:29546) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 3)
(node:29546) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

[ammarkarachi]

@marlonmarcello Can you IM me on our discord community so I can reproduce this issue?
@dwamianm Can you share your schema?

[yuth]

@dwamianm this seems to be a different issue from the stack trace. Could you try clearing the ESM cache by deleting /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/.cache/esm and see if you still have the same issue

[marlonmarcello]

I think that link expired @ammarkarachi

[marlonmarcello]

@yuth when I do npm -g remove @aws-amplify/cli that folder is gone

[yuth]

@yuth when I do npm -g remove @aws-amplify/cli that folder is gone

THE ESM cache removal was one possible solution for this and not the original issue.

^X^C(node:29546) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'stop' of undefined
at APITest. (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:82:41)
at Generator.next ()
at /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:8:71
at new Promise ()
at __awaiter (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:4:12)
at APITest.stop (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:66:16)
at APITest. (/usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:36:32)
at Generator.next ()
at /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js:8:71
at new Promise ()
(node:29546) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 3)
(node:29546) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

The original issue has to do something with CFN parsing and it would make it easier if we could get the stack trace.

[marlonmarcello]

I removed the cli, deleted the project, cleared npm cache and removed all folders from the npm bin.

Then I proceeded to install the cli again, and start a new project with the schema above and I still got the same issue on 4.21
Failed to start API Mock endpoint TypeError: Cannot read property '0' of null

[dwamianm]

@yuth . I tried removing the cache as you recommended and then I removed the cli all together. I then generated a brand new project with minimal schema file. The issue continued to happen so I followed the output I posted earlier and found where things were failing.

The issue seems to be happening in the method checkJavaVersion. When I comment out the line yield index_1.checkJavaVersion(context); in the generated JS file /usr/local/lib/node_modules/@aws-amplify/cli/node_modules/amplify-util-mock/lib/api/api.js things worked. Which means it was failing at the Java version check.

I ended up digging up this related issue.

https://github.com/aws-amplify/amplify-cli/issues/3319

Since Java was already installed on my Mac, I ran brew cask reinstall java on my machine which seems to have fixed the issue.

@marlonmarcello @ammarkarachi FYI

[marlonmarcello]

That was it!
Thanks a lot @dwamianm !!

[darwinbatres]

just as fyi, Issue is still happening on amplify version 4.21.3 on Catalina 10.15.5,
brew cask reinstall java also fixed the issue for me