Get ApiId or Table Name in custom handler

[godrimcom]

Environment information

System:
  OS: macOS 14.5
  CPU: (10) arm64 Apple M1 Pro
  Memory: 153.83 MB / 16.00 GB
  Shell: /bin/zsh
Binaries:
  Node: 20.12.0 - ~/.nvm/versions/node/v20.12.0/bin/node
  Yarn: undefined - undefined
  npm: 10.5.0 - ~/.nvm/versions/node/v20.12.0/bin/npm
  pnpm: undefined - undefined
NPM Packages:
  @aws-amplify/backend: 1.0.0
  @aws-amplify/backend-cli: 1.0.1
  aws-amplify: 6.3.8
  aws-cdk: 2.140.0
  aws-cdk-lib: 2.140.0
  typescript: 5.4.5
AWS environment variables:
  AWS_STS_REGIONAL_ENDPOINTS = regional
  AWS_NODEJS_CONNECTION_REUSE_ENABLED = 1
  AWS_SDK_LOAD_CONFIG = 1
No CDK environment variables

Description

I'm using amplify gen 2 and I added a custom handler in my schema:

deleteTickets: a
    .mutation()
    .arguments({
      ids: a.id().array(),
    })
    .returns(a.json())
    .authorization((allow) => [allow.authenticated()])
    .handler(
      a.handler.custom({
        dataSource: a.ref('Ticket'),
        entry: './handlers/tickets/deleteTickets.js',
      })
    ),

this is my handler:

export function request(ctx) {
  const { ids } = ctx.args

  return {
    operation: 'BatchDeleteItem',
    tables: {
      TABLE_NAME: ids.map((id) => util.dynamodb.toMapValues({ id })),
     // How can I access the table name? in ctx. This is the actual table name Ticket-ruzu7wa7dzcbflfe2qpamijr5a-NONE
    },
  }
}

export function response(ctx) {
  if (ctx.error) {
    util.error(ctx.error.message, ctx.error.type)
  }
  return ctx.result || {}
}

I just want to do a BatchDeleteItem operation. This should be a basic operation, please help

[ykethan]

Hey,👋 thanks for raising this! I'm going to transfer this over to our API repository for better assistance 🙂

[AnilMaktala]

Hey @godrimcom, Thank you for bringing this up. Could you please clarify if you have already reviewed the relevant documentation on this topic?

[chrisbonifacio]

Hi @godrimcom At the moment there is no way, at least that I'm aware of, to access and pass the table name to a resolver without incurring a "circular dependency" error. You may have to hard code the table name and pass it as an environment variable.

ex:

backend.data.resources.cfnResources.cfnGraphqlApi.environmentVariables = {
  TODO_TABLE:
    // replace with your own table name
    `Todo-md4n36jl7za7xi4mie3cs3wyey-NONE`,
};

in the resolver you'd access environment variables from the context:

import { util } from "@aws-appsync/utils";

export const request = (ctx) => {
  const todos = [];

  ctx.args.todos.forEach(({id}) => {
    todo.push(util.dynamodb.toMapValues({ id }));
  });

  return {
    operation: "BatchGetItem",
    tables: {
      [ctx.env.TODO_TABLE]: {
        keys: todos,
      },
    },
  };
};

export const response = (ctx) => {
  return ctx.result.data[ctx.env.TODO_TABLE];
};

we are working on a way to make the DDB tables accessible.

UPDATE: You can also compute the name of the table because it will be in the format <model>-<apiId>-<environment>.

I'm not sure what determines <environment>, in my sandbox environment it's set to NONE, hence the table name "Todo-md4n36jl7za7xi4mie3cs3wyey-NONE"

[andrew-clark-dev]

Hi @chrisbonifacio , just checking that you know you can access the table name from the data resources. So

const { tables } = backend.data.resources

backend.data.resources.cfnResources.cfnGraphqlApi.environmentVariables = {
  TODO_TABLE: tables['Todo'],
};