Serverless deployed lambda callbacks extremely slow

Serverless Framework
1

All my lambdas with callbacks deployed by serverless when invoked have durations around 5960ms. (Lambda timeout set to 6 seconds… peculiar)
The same code written in the AWS lambda inline editor, has the normal duration 100ms etc.

This is only if module.exports.handler has a callback and is not async.
So I’m just converting my handler functions to async which I should have already done.

Has anyone else experienced this? Not too worried about getting this resolved, just curious.

Chur

2

Would have to see the handler code, but what appears to be the most common cause is failure to call the callback at the end of the function.

3 
const AWS = require('aws-sdk');
const dynamodb = new AWS.DynamoDB({ region: "us-east-1",napiVersion: "2012-08-10"});

exports.handler = (event, context, callback) => {
  const userToMarkInactive = event.userToMarkInactive;
  const params = {
    ExpressionAttributeNames: {
      "#AT": "active"
    },
    ExpressionAttributeValues: {
      ":t": {
        BOOL: false
      }
    },
    Key: {
      Username: {
        S: "" + userToMarkInactive
      }
    },
    ReturnValues: "ALL_NEW",
    TableName: process.env.UsersTable,
    UpdateExpression: "SET #AT = :t"
  };
  dynamodb.updateItem(params, function(err, data) {
    if (err) {
      console.log(err);
      callback(err);
    } else {
      console.log(data);
      callback(null, data);
    }
  });
};
4

Hmm… I don’t see any issues.
To confirm I went ahead and whipped up a simple service with your code and it’s returning as expected:

First invocation:
REPORT RequestId: 4b88f946-3c65-4ba6-aaca-8a27bff70320 Duration: 128.67 ms Billed Duration: 200 ms Memory Size: 1024 MB Max Memory Used: 77 MB Init Duration: 205.88 ms

Subsequent invocations:

REPORT RequestId: 95f041dd-6a19-40c3-9e65-d1153c8b422a  Duration: 27.90 ms      Billed Duration: 100 ms Memory Size: 1024 MB    Max Memory Used: 77 MB
REPORT RequestId: 4d607472-2e11-40ec-8ce7-bf6423f95411  Duration: 27.52 ms      Billed Duration: 100 ms Memory Size: 1024 MB    Max Memory Used: 77 MB
REPORT RequestId: d0348c35-c8f3-4fad-a071-409c4e030b9b  Duration: 27.25 ms      Billed Duration: 100 ms Memory Size: 1024 MB    Max Memory Used: 77 MB

Invocation command:
sls invoke -s brett -f hello -d '{"userToMarkInactive":"joe"}' -l

Here’s my serverless.yml:

service: simple

plugins:
  - serverless-pseudo-parameters

provider:
  name: aws
  runtime: nodejs8.10
  stage: brett
  region: ${opt:region, 'us-west-2'}

  environment:
    UsersTable: ${self:provider.stage}-users

  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:*
      Resource:
        - arn:aws:dynamodb:#{AWS::Region}:#{AWS::AccountId}:table/${self:provider.stage}-users

functions:
  hello:
    handler: handler.handler

resources:
  Resources:
    UserTable:
      Type: AWS::DynamoDB::Table
      DeletionPolicy: Delete
      Properties:
        AttributeDefinitions:
          - AttributeName: Username
            AttributeType: S
        BillingMode: PAY_PER_REQUEST
        KeySchema:
          - AttributeName: Username
            KeyType: HASH
        TableName: ${self:provider.stage}-users

and the handler function:

const AWS = require('aws-sdk');
const dynamodb = new AWS.DynamoDB({ region: "us-west-2", napiVersion: "2012-08-10"});

exports.handler = (event, context, callback) => {
  const userToMarkInactive = event.userToMarkInactive;
  const params = {
    ExpressionAttributeNames: {
      "#AT": "active"
    },
    ExpressionAttributeValues: {
      ":t": {
        BOOL: false
      }
    },
    Key: {
      Username: {
        S: "" + userToMarkInactive
      }
    },
    ReturnValues: "ALL_NEW",
    TableName: process.env.UsersTable,
    UpdateExpression: "SET #AT = :t"
  };
  dynamodb.updateItem(params, function(err, data) {
    if (err) {
      console.log(err);
      callback(err);
    } else {
      console.log(data);
      callback(null, data);
    }
  })
}

Built and deployed with Serverless 1.53.0