How do I add trigger to an AWS Lambda function using AWS CLI?

Question

Any way of doing this using AWS CLI?

Answer 1

I was able to add SNS trigger for lambda using below AWS CLI

aws lambda add-permission \
  --function-name {{LAMBDA-FUNCTION-NAME}} \
  --statement-id {{UNIQUE-ID}} \
  --action "lambda:InvokeFunction" \
  --principal sns.amazonaws.com \
  --source-arn arn:aws:sns:us-east-1:77889900:{{SNS-TOPIC-ARN}}

The SNS topic can also be from other region.
Hope this helps.

Answer 2

As @user1292364 mentioned we need to use add-permission to the lambda.

Only issue with it is that you need to make sure that lambda to sns subscription is added also. Otherwise this error will occur

A subscription for arn:aws:lambda:eu-west-1:276xxxxxx:function:HourlyLambdaFunction on the topic HourlyLambdaFunction could not be found.

I would prefer to use it over AWS CLI in this way:

#!/usr/bin/env bash

# Add Lambda to SNS as subscription
aws sns subscribe \
    --topic-arn arn:aws:sns:eu-west-1:276xxxxxx:HourlyLambdaFunction \
    --protocol lambda \
    --notification-endpoint arn:aws:lambda:eu-west-1:276xxxxxx:function:HourlyLambdaFunction

# Give permissions to Lambda to access that subscription i.e. Add it through triggers
aws lambda add-permission \
    --function-name HourlyLambdaFunction \
    --statement-id 276xxxxxx\
    --action "lambda:InvokeFunction" \
    --principal sns.amazonaws.com \
    --source-arn arn:aws:sns:eu-west-1:276xxxxxx:HourlyLambdaFunction

# Send message to publish and trigger lamda
aws sns publish \
    --topic-arn arn:aws:sns:eu-west-1:276xxxxxx:HourlyLambdaFunction \
    --subject "HourlyLambdaFunction" \
    --message "{datawarehouse:banana_wh, database:banana_db, schema:banana. query:'select count(*) from banana.banana_loads;'}"

ps: \ in the code is new line for bash script (if anyone wonders)

Logs of the lambda function can be found on Cloudwatch