APL interpreter runtime for AWS lambda

Note: Dyalog APL interpreter license

   Dyalog interpreter used in this project part of Dyalog docker image  dyalog/dyalog on Linux and
   THAT IS NON COMMERCIAL VERSION OF DYALOG INTERPRETER.
   Please, check the Dyalog APL interpreter license with Dyalog ltd at http://wwww.dyalog.com

In example the Dyalog binaries are at: ./dyalog/opt/mdyalog The files can be extracted as describe at How to get Dyalog Linux binaries from Dyalog image . Dyalog will make general available NON COMMERCIAL version of interpreter.

How to use APL lambda

Develop your APL code on desktop

Save as aplHandler.apl:

  res←aplHandler arg;event;context;deadline
  event context←arg
  ⎕←'Hi from APL (handler) on AWS Lambda!'
  deadline←⍎⊃context.deadlineMs
  myFn ⍝ Call to another function from MyLib.dws
  ⎕←'There is '(#.AplLambdaNsName.getRemainingTimeInMillis deadline ⎕TS)' ms remaining.'
  res←event

Save as index.package.json:

  {
    "DyalogFiles" : ["AplHandler.aplf"],
    "DwsFiles" : []
  }

This is package information as in AWS lambda placing of files must be defined explicitly.

Then bundle up into a zipfile – this is your function bundle:

  zip -yr lambda.zip aplHandler.dyalog index.package.json 

There can be also DWS files with library to zip file.

The code for example could found in ./18.0.0/test folder.

Lets go to Cloud

You should have account on Amazon AWS cloud at https://aws.amazon.com/ .

Open the Lambda console .

Within this project is provided Lambda layer at ./17.1.0/layer.zip . It includes APL interpreter too. This layer might be used in next step.

Add layer to AWS Lambda:

Result will be:

Create a new Lambda function and choose the custom runtime option.

Do not forget: Select your index.zip as the "Function code" and change the handler form "index.handler" to "index.aplHandler".

Then click on Layers and choose "Add a layer", and "Provide a layer version ARN" and enter the following ARN:

arn:aws:lambda:us-east-2:882298957436:layer:Dyalog_APL_17_0:1

Then save your lambda (press Save button) and test it with a test event!

Current Version ARNs

Version	ARN	Description
1	arn:aws:lambda:us-east-2:882298957436:layer:Dyalog_APL_17_0:1	Dyalog APL runtime

Create Dyalog APL AWS lambda layer

Build APL code DWS code

In order to build APL code to dws file How to get Dyalog Linux binaries from Dyalog image

Build layer.zip

To build layer.zip use build.sh

To test layer local

To test use test.sh

Error message

On error JSON error message is created:

{
  "errorType": "6",
  "errorMessage": " VALUE ERROR\\n aplHandler[7] aæa\u0026∇ ⍺ ⍵⌶⌸⌸⍠⎕⍞⍤.⍨⍉⌽⍴⍴⍀∪∊⍒⍋æsæd\\n                                          ∧\\n
Undefined name: æsæd",
  "stackTrace": [
    "#.AplLambdaNsName.lambdaexec2019916212526435198.aplHandler[7]",
    "#.AplLambdaNsName.callHandler[26]",
    "#.AplLambdaNsName.processEvents[47]",
    "#.AplLambdaNsName.start[3]",
    "#.AplLambdaNsName.aplLambdaBootstrap[57]",
    "#.loadAplLambda[6]"
  ]
} 

To decode UTF-8 value error message can be used:

  'UTF-8' ⎕UCS  ⎕UCS errorMessage

Unicode encode and decode the data

The layer implements encode and decode of data as:

encode to ANSI

   ⎕UCS 'UTF-8' ⎕UCS errorMessage

decode to UTF-8

  'UTF-8' ⎕UCS  ⎕UCS errorMessage

Environment variables

APLASYNC - Async/Await on of

Setting APLASYNC to 1 are used async await model. Using this can be overhead, therefore default value for APLASYNC is 0.

APLLOG - Logging flag

There are 5 levels of logging and integer value of APLLOG enables logging level:

1. [ERROR] - Error
2. [WARN] - Warring
3. [INFO] - Information
4. [DEBUG] - Debug

• any other value - [MISC] - Miscellaneous

Notes:

1. The event body should be esaped in the test: '{"name":"vale"}'
2. The shell (sh) scripts likes LF instead CRLF. That can be issues if you run it from powershell with Linux subsystem.

See

1. Dyalog APL interpret home http://www.dyalog.com
2. AWS Lambda Custom runtime https://docs.aws.amazon.com/lambda/latest/dg/runtimes-custom.html
3. Some custom runtime https://github.com/mthenw/awesome-layers
4. https://github.com/lambci/docker-lambda
5. https://github.com/lambci/node-custom-lambda