Failure building an AWS Lambda custom runtime for Typescript with Deno

Now AWS Lambda supports custom runtime. And there is TypeScript runtime called Deno. Is it possible to run ‘.ts’ in Lambda using Deno? Let’s try it. Never mind the title.

What is Deno

Deno is a secure JavaScript / TypeScript runtime built on V8. It is led by Ryan Dahl who created Node.js. If you are interested in Deno, check his presentation at JSConf EU 2018.

What is a custom runtime

Simply, you can also run a function in any language that is not provided by AWS. A runtime is a program that runs a Lambda function. You can build your own runtime to run some other languages.

Building a custom runtime

Download Deno from Github repository, unzip it, and rename deno_linux_x64 to deno.

.
└─ deno

According to Custom AWS Lambda runtimes, the runtime is responsible for jobs including getting an event and a context, invoking the function, and handling the response or errors. Instead of implementing them, I forked lambci/node-custom-lambda and migrate bootstrap.js code to runtime.ts for Deno. Here is runtime.ts.

.
├─ deno
└─ runtime.ts

A custom runtime’s entry point is an executable file named bootstrap. Make a shell script file named bootstrap invoking runtime.ts.

bootstrap
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#!/usr/bin/env bash
/opt/deno --allow-all /opt/runtime.ts
.
├─ bootstrap
├─ deno
└─ runtime.ts

Zip these files and create a Lambda layer. If you don’t have aws-cli, install it

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$ zip -r layer.zip bootstrap deno runtime.ts
$ aws lambda publish-layer-version \
    --layer-name deno_027 \
    --description "Deno v0.2.7" \
    --compatible-runtimes provided \
    --license-info MIT \
    --zip-file fileb://layer.zip

Add new file named function.ts, zip it, and create a lambda function. Replace ARNs to yours in below snippet.

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$ echo "export const handler = () => ({ Hello: 'World!' })" >> function.ts
$ zip -r function.zip function.ts
$ aws lambda create-function \
    --function-name deno-test \
    --runtime provided \
    --role arn:aws:iam::xxxxxxxxxxxx:role/lambda-role \
    --handler function.handler \
    --layers arn:aws:lambda:ap-northeast-2:xxxxxxxxxxxx:layer:deno_027:1 \
    --zip-file fileb://function.zip

Now it is time to try.

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$ aws lambda invoke --function-name deno-test response.txt

See the response.txt. Fail…

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{
  "errorType": "Runtime.ExitError",
  "errorMessage": "RequestId: c25b323a-c386-44c6-b147-9273deee0ab9 Error: Runtime exited with error: exit status 1"
}

On the CloudWatch log, I see this message.

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/opt/deno: /lib64/libc.so.6: version `GLIBC_2.18' not found (required by /opt/deno)

Deno requires GLIBC_2.18 which is not included in Lambda container environment. There is no way to install it to Lambda container environment.

I think ts-node might be a custom runtime, but I’m not attracted to that than Deno.