jmglov's blog
A blog about stuff but also things.
A blog about stuff but also things.
When last we left the epic tale of me trying to use a thing that I made myself and then being outraged at how poorly made the thing was, I had just gotten dependencies stuffed in a lambda layer and proved that it worked by deploying a lambda that listed some files from an S3 bucket. Hurrah!
Of course, I ended that post by complaining about the incredibly bad UX of the thing I had built, and a vague promise to make it less incredibly bad (never let good be the enemy of less bad!). Since last we spoke, I did just that. Check it out!
So I create a directory called my-lambda, then add a bb.edn like this:
{:deps {net.jmglov/blambda
#_"You use the newest SHA here:"
{:git/url "https://github.com/jmglov/blambda.git"
:git/sha "2453e15cf75c03b2b02de5ca89c76081bba40251"}}
:tasks
{:requires ([blambda.cli :as blambda])
blambda {:doc "Controls Blambda runtime and layers"
:task (blambda/dispatch)}}}
This is enough to let me use Blambda:
$ bb blambda
Usage: bb blambda <subcommand> <options>
All subcommands support the options:
--target-dir <dir> target Build output directory
--work-dir <dir> .work Working directory
Subcommands:
build-runtime-layer: Builds Blambda custom runtime layer
--bb-version <version> 0.9.161 Babashka version
--bb-arch <arch> Architecture to target (use amd64 if you don't care)
build-deps-layer: Builds dependencies layer from bb.edn or deps.edn
--deps-path <path> Path to bb.edn or deps.edn containing lambda deps
deploy-runtime-layer: Deploys Blambda custom runtime layer
--aws-region <region> eu-west-1 AWS region
--runtime-layer-name <name> blambda Name of custom runtime layer in AWS
--bb-arch <arch> amd64 Architecture to target
deploy-deps-layer: Deploys dependencies layer
--aws-region <region> eu-west-1 AWS region
--deps-layer-name <name> Name of dependencies layer in AWS
clean: Removes work and target folders
I can create a Blambda runtime:
$ bb blambda build-runtime-layer --help
Usage: bb blambda build-runtime-layer <options>
Options:
--target-dir <dir> target Build output directory
--work-dir <dir> .work Working directory
--bb-version <version> 0.9.161 Babashka version
--bb-arch <arch> Architecture to target
$ bb blambda build-runtime-layer --bb-arch arm64
Downloading https://github.com/babashka/babashka/releases/download/v0.9.161/babashka-0.9.161-linux-aarch64-static.tar.gz
Decompressing .work/babashka-0.9.161-linux-aarch64-static.tar.gz to .work
Adding file bootstrap
Adding file bootstrap.clj
Compressing custom runtime layer: ~/my-lambda/target/bb.zip
And deploy it:
$ bb blambda deploy-runtime-layer --bb-arch arm64
Publishing layer version for layer blambda
Published layer arn:aws:lambda:eu-west-1:289341159200:layer:blambda:1
Now, let's say I want my lambda to do S3 stuff using awyeah-api. I'll create a src directory and drop a bb.edn in there:
{:paths ["."]
:deps {com.cognitect.aws/endpoints {:mvn/version "1.1.12.206"}
com.cognitect.aws/s3 {:mvn/version "822.2.1109.0"}
com.grzm/awyeah-api {:git/url "https://github.com/grzm/awyeah-api"
:git/sha "0fa7dd51f801dba615e317651efda8c597465af6"}
org.babashka/spec.alpha {:git/url "https://github.com/babashka/spec.alpha"
:git/sha "433b0778e2c32f4bb5d0b48e5a33520bee28b906"}}}
I can now use Blambda to create a lambda layer containing all my dependencies:
$ bb blambda build-deps-layer
Missing required arguments: --deps-path
Usage: bb blambda build-deps-layer <options>
Options:
--target-dir <dir> target Build output directory
--work-dir <dir> .work Working directory
--deps-path <path> Path to bb.edn or deps.edn containing lambda deps
Oops! Looks like I forgot the --deps-path argument. Let's try that again:
$ bb blambda build-deps-layer --deps-path src/bb.edn
Cloning: https://github.com/grzm/awyeah-api
Downloading: com/cognitect/aws/endpoints/1.1.12.206/endpoints-1.1.12.206.pom from central
Downloading: org/clojure/clojure/1.11.1/clojure-1.11.1.pom from central
Downloading: com/cognitect/aws/s3/822.2.1109.0/s3-822.2.1109.0.pom from central
Checking out: https://github.com/grzm/awyeah-api at 0fa7dd51f801dba615e317651efda8c597465af6
Cloning: https://github.com/babashka/spec.alpha
Checking out: https://github.com/babashka/spec.alpha at 433b0778e2c32f4bb5d0b48e5a33520bee28b906
Downloading: org/clojure/spec.alpha/0.3.218/spec.alpha-0.3.218.pom from central
Downloading: org/clojure/core.specs.alpha/0.2.62/core.specs.alpha-0.2.62.pom from central
Downloading: org/clojure/pom.contrib/1.1.0/pom.contrib-1.1.0.pom from central
Downloading: com/cognitect/aws/endpoints/1.1.12.206/endpoints-1.1.12.206.jar from central
Downloading: com/cognitect/aws/s3/822.2.1109.0/s3-822.2.1109.0.jar from central
Downloading: org/clojure/spec.alpha/0.3.218/spec.alpha-0.3.218.jar from central
Downloading: org/clojure/clojure/1.11.1/clojure-1.11.1.jar from central
Downloading: org/clojure/core.specs.alpha/0.2.62/core.specs.alpha-0.2.62.jar from central
Classpath before transforming: src:~/my-lambda/.work/m2-repo/com/cognitect/aws/endpoints/1.1.12.206/endpoints-1.1.12.206.jar:...
Classpath after transforming: src:/opt/m2-repo/com/cognitect/aws/endpoints/1.1.12.206/endpoints-1.1.12.206.jar:...
Compressing custom runtime layer: ~/my-lambda/target/deps.zip
What that wall of text (sorry about that!) is saying is that Blambda is downloading all of the dependencies my lambda has declared in bb.edn and zipping them up into a layer, which I can deploy like this:
$ bb blambda deploy-deps-layer --deps-layer-name my-lambda-deps
Publishing layer version for layer my-lambda-deps
Published layer arn:aws:lambda:eu-west-1:289341159200:layer:my-lambda-deps:1
It is a little annoying to have to remember those arguments every time, so let's see what we can do about that. If I go back to my top-level bb.edn, I can specify some defaults for my lambda:
{:deps {net.jmglov/blambda
#_"You use the newest SHA here:"
{:git/url "https://github.com/jmglov/blambda.git"
:git/sha "2453e15cf75c03b2b02de5ca89c76081bba40251"}}
:tasks
{:requires ([blambda.cli :as blambda])
:init (def opts {:deps-path "src/bb.edn"
:deps-layer-name "my-lambda-deps"
:bb-arch "arm64"})
blambda {:doc "Controls Blambda runtime and layers"
:task (blambda/dispatch opts)}}}
By adding the opts there, I've saved myself the trouble of typing --bb-arch, --deps-path, and --deps-layer-name:
$ bb blambda build-deps-layer
Classpath before transforming: src:~/my-lambda/.work/m2-repo/com/cognitect/aws/endpoints/1.1.12.206/endpoints-1.1.12.206.jar:...
Classpath after transforming: src:/opt/m2-repo/com/cognitect/aws/endpoints/1.1.12.206/endpoints-1.1.12.206.jar:...
Compressing custom runtime layer: ~/my-lambda/target/deps.zip
I can now create a lambda in the AWS console that uses Blambda and my deps layer.
Now I need to add the custom runtime layer:
And the deps layer:
Looks nice! Now how about some Clojure code that does something exciting?
We can delete the files that AWS has put there and replace them with a my_lambda.clj that looks like this:
(ns my-lambda
(:require [cheshire.core :as json]))
(defn handler [event _context]
(let [body {:msg "Lambda handler invoked"
:data {:event event}}]
(prn body)
{:status 200
:body (json/generate-string body)}))
The Cheshire JSON library is included free of charge by Babashka, so we can play with JSON despite not mentioning it in our src/bb.edn. Amazing!
We also need to change Runtime settings > Handler to my-lambda/handler, then click the Deploy button to get our lambda out there in the world!
After deploying, we excitedly click the Test button, only to be told that we need to configure a test event! 😭 No matter, we'll just go with the hello-world template and hope for the best.
Now that we have a test event configured, let's click Test again... and celebrate a job well done! 🎉
I had actually intended to explain the CLI stuff in this post, but this is already a bit long and my dog is starting to give me meaningful looks, so I'd better end this thrilling instalment of Dogfooding Blambda here and take him out for a walk.