serverless/docs/providers/aliyun/guide/functions.md

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Alibaba Cloud - Functions

If you are using Alibaba Cloud Function Compute as a provider, all functions inside the service are Alibaba Cloud Function Compute functions.

Configuration

All of the Alibaba Cloud Function Compute in your serverless service can be found in serverless.yml under the functions property.

# serverless.yml
service: my-aliyun-service

provider:
  name: aliyun

plugins:
  - serverless-aliyun-function-compute

functions:
  first:
    handler: index.hello
    events:
      - http:
          path: /foo
          method: get

Handler

The handler property should be the function name you've exported in your entrypoint file.

When you e.g. export a function with the name hello in index.js your handler should be handler: index.hello.

// index.js
exports.hello = (event, context, callback) => {};

Memory size and timeout

The memorySize and timeout for the functions can be specified on the provider or function level. The provider wide definition causes all functions to share this config, whereas the function wide definition means that this configuration is only valid for the function.

The default memorySize is 128 MB and the default timeout is 30s if not specified.

# serverless.yml

provider:
  memorySize: 512
  timeout: 90s

functions:
  first:
    handler: first
  second:
    handler: second
    memorySize: 256
    timeout: 120s

Handler signatures

The signature of an event handler is:

function (event, context, callback) { }

event

If the function is triggered by a HTTP event without the bodyFormat specified, the event passed to the handler will be:

// event
{
  type: 'Buffer',
  // A buffer containing a JSON string of data about the incoming request
  data: [ ... ]
}

// `JSON.parse(Buffer.from(event.data).toString())`
// would yield an object similar to the one below (with `bodyFormat` specified)

If the bodyFormat is specified, the event passed to the handler will be something like this:

// event
{
  body: '',
  headers: { ... },
  httpMethod: 'GET',
  isBase64Encoded: false,
  path: '/test',
  pathParameters: { ... },
  queryParameters: { ... }
}

If the function is triggered by an OSS event, then the event would be a JSON string containing data about the event:

// JSON.parse(event)
{
  events: [{
    eventName: 'ObjectCreated:PostObject',
    eventSource: 'acs:oss',
    eventTime: '2017-09-15T03:23:17.000Z',
    eventVersion: '1.0',
    oss: {
      bucket: {
        arn: 'acs:oss:cn-shanghai:xxx:my-service-resource',
        name: 'my-service-resource',
        ownerIdentity: 'xxx',
        virtualBucket: ''
      },
      object: {
        deltaSize: 585,
        eTag: '...',
        key: 'source/some.object',
        size: 585
      },
      ossSchemaVersion: '1.0',
      ruleId: '...'
    },
    region: 'cn-shanghai',
    requestParameters: { ... },
    responseElements: { ... },
    userIdentity: { ... }
  }]
}

context

The context argument contains information about the function and the service. The credentials in context.credentials can be used to access other Alibaba Cloud resources.

{
  requestId: '...',
  credentials: {
    accessKeyId: '...',
    accessKeySecret: '...',
    securityToken: '...'
  },
  function: {
    name: '...'
    handler: '...'
    memory: 128,
    timeout: 30
  }
}

callback

The callback argument is a callback taking an error and a response:

exports.http = (event, context, callback) => {
  const response = {
    statusCode: 200,
    body: JSON.stringify({ message: 'Hello World!' }),
  };

  callback(null, response);
};