Articles, notes and random thoughts on Software Development and Technology
If you invoke a Lambda and include the —log-type Tail param, you’ll get a bunch of encoded output like:
{
"StatusCode": 200,
"LogResult": "MDIxLTA3LTE4IDAzOjAzOjU...
To decode it to readable output, you need to pipe it into a base64 util to decode, like:
aws lambda invoke local --region us-west-1 --function-name your-function-name --log-type Tail | base64 -d
This is covered in the docs here.
‘aws lambda list-functions’ returns function details in your current region, but the info is sometimes too verbose when you’re looking for a list of names:
{
"Functions": [
{
"FunctionName": "example1",
"FunctionArn": "arn:aws:lambda:us-west-2:111111111:function:example1",
"Runtime": "java8",
"Role": "arn:aws:iam::111111111:role/example-role",
"Handler": "package.YourHandler::myHandler",
"CodeSize": 3381385,
"Description": "",
"Timeout": 6,
"MemorySize": 1024,
"LastModified": "2021-01-13T08:18:33.727+0000",
"CodeSha256": "aaabbbccc=",
"Version": "$LATEST",
"TracingConfig": {
"Mode": "PassThrough"
},
"RevisionId": "aa-bb-cc-dd"
},
{
"FunctionName": "example2",
"FunctionArn": "arn:aws:lambda:us-west-2:111111111:function:example2",
"Runtime": "java8",
"Role": "arn:aws:iam::111111111:role/example-role",
"Handler": "package.YourHandler2::myHandler",
"CodeSize": 3381385,
"Description": "",
"Timeout": 6,
"MemorySize": 1024,
"LastModified": "2021-01-13T08:18:33.727+0000",
"CodeSha256": "aaabbbccc=",
"Version": "$LATEST",
"TracingConfig": {
"Mode": "PassThrough"
},
"RevisionId": "aa-bb-cc-dd"
}
]
}
Passing this into JQ you can filter to display any of the properties easily with patterns like:
aws lambda list-functions | jq '.Functions[].FunctionName
To configure an AWS Lambda to get triggered by a CloudWatch event, you can use the ‘schedule’ event in your config:
functions:
your-function-name:
handler: your.Handler
timeout: 30
events:
- schedule:
rate: rate(12 hours)
input:
puzzles : "2"
targetGivens : "20"
You can also pass parameters from the CloudWatch event when your Lambda is invoked by listing them under ‘input’ (this is optional if your Lambda doesn’t take any parameters).
There schedule config is covered in the docs here, but there doesn’t seem to be any official docs for input, but I found this in a reply to a question here.
If you deploy a Serverless Framework Java Lambda to AWS and attempt to call it locally while developing your frontend, you’ll run into a CORS error like this:
Access to XMLHttpRequest at 'https://abc.execute-api.us-west-1.amazonaws.com/some/api' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Posts suggest to set a cors option under the event in your serverless.yaml like this:
events:
- http:
path: handlerPath
method: post
cors:
origin: '*'
… but in current versions of Serverless this results in an error like this:
Serverless: at 'functions['example'].events[0].httpApi': unrecognized property 'cors'
From this post, it mentions the cors options has moved up into the provider section:
provider:
name: aws
runtime: java8
lambdaHashingVersion: 20201221
httpApi:
cors: true
This is in the docs here.
This works great!
What does this option do? It looks like it sets these options in API Gateway:
