如何在Javascript / Nodejs Lambda函数中获取AWS区域：

Question

How do I identify the region from within a Nodejs/Javascript AWS Lambda function?

The AWS_DEFAULT_REGION environment variable gives a ReferenceError (See here , which is for Java, not Node/Javascript.)

I realize I can get the "invokedFunctionArn" from the context object and parse it for the region, but it seems like there should be a more direct way.

Answer 1

Use the environment variable:

process.env.AWS_REGION

Source: http://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html#lambda-environment-variables

Answer 2

You can take a look at the context that is passed in. There maybe more goodies to discover there.

exports.handler = function(event, context) {
    console.log('Function name:', context.functionName);
    context.succeed();
};

I don't know anything that simply tells you the region. An ugly hack would be exec-ing something in the containing OS (linux) and hoping for the info to show up. uname -a perhaps.

I'm just curious. What do you need it for? Some kind of debugging info?

Answer 3

There just doesn't seem to be a more direct way to identify the region in a running lambda function, other than using context.invokedFunctionArn property.

Here's what I ended up doing:

exports.handler = (event,context, callback) => {
    var arnList = (context.invokedFunctionArn).split(":");
    var lambdaRegion = arnList[3] //region is the fourth element in a lambda function arn


    //more code
}