How to use layers with Lambda functions?

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In this video we look at how to use layers with AWS Lambda functions. (with nodejs)
We look at a demo app which uses two npm modules (axios and image-size) which were installed using npm and are part of the bundle. We then extract these modules into a layer. We attach this layer to our function and import and use the modules we extracted.
It has 2 advantages:
it reduces the size of the bundle
it makes it possible to re-use the extracted code across several functions.
We also look at how to separate local files and extract them into a layer and then import them from the function.
If you would like to see an example of using layers, check out this video • How to use ImageMagick... in which we use a layer to install ImageMagick to resize images within a lambda function.
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#lambda #layers #nodejs

[@BiteSizeAcademy]

⚡️ NEW VIDEO: How to use versioning and aliases to deploy lambda functions? (/w API Gateway) th-cam.com/video/OGMaE63YgEU/w-d-xo.html

[@rohitkrishnan5456]

Hey BiteSize Academy, Great work! I have learnt a lot from your videos.. Can you make a video with a monorepo setup for deploying multiple lambdas (using lambda layers for common modules)? I think it a real world use case and might help a lot of people :)

[@nallibtala3800]

I will never understand...
why every time I have doubts, the official documentation is useless.
But forums and users explain really nice

[@niravarma]

Simple and straightforward. Really helpful.

[@nichenjie]

[6:48] If you put `util.js` file inside `node_modules/` folder in the layer, you can do `require('utils')` directly without hardcoding the `/opt` path.

[@cristhianvalencia5793]

I don't think is a good idea to put things inside the node_modules folder. Unless you have implemented a hook after npm install, the file will not be added automagically (usually the node_modules folder is not committed to the git repository)

[@rohitkrishnan5456]

@@cristhianvalencia5793 it can be done as part of the build step...maybe util.js lives in a lib folder and gets copied when the lambda layer is deployed

[@McMurdoStation]

Thanks. I was hoping such a thing was possible but hadn't learned how until this video.

[@colin-vandervoort]

Just the right amount of information, and great pacing, thanks!

[@eduardboiko7219]

Was instantly useful, thanks for the video!

[@adrianarizpe7397]

This was extremely helpful and simple. Thank you!

[@luvodlulisa7883]

This really helped me out, thanks bro.

[@AnhNguyen-vu7mc]

How do you do local testing for layer import? /Opt I assume is not the right path in local machine

[@deyvisonborges]

send to local /nodejs/node_modules/your_lib and referece in
tsconfig.json
paths: {
"/nodejs/node_modules/yourpackage": ["/nodejs/node_modules/yourpackage"]
}
import { item } from "/nodejs/node_modules/yourpackage"

[@GuillermoCervantes-v5v]

Do you know the structure of a layer in ES6 V3 for node22 or node20 with import statements. I follow this tutorial, and AWS guides. Mostly "package.json" has the element "type: "module". The modules are unzip and loaded, but the "opt/directory" or the JS files are not found.

[@testatestb]

Thanks! Its helpful :)

[@matthewhill3556]

Perfect explanation! Thanks a lot :)

[@RC-vr7fl]

Great succinct presentation. Many thanks.

[@in.hardikwts]

How youm put this file in function e.g. node_modules, package.json etc file which you remove at 6:35

[@ashil816]

Really appreciate if you can make a video in kinesis-data-stream and lambda function to consume the stream

[@lonewolf2547]

simple and straight to point

[@kfliden]

How would this work with CloudFormation or SAML can you specify a layer there as well? Great video!

[@chrismuh5337]

thank you very good video and well explained

[@ZacLow]

you mean, after creating the layer, the codes in the layer don't run anymore? which makes the bundle much faster?

[@karimfayed3050]

Great Video! It is really helpful. But I do have a question. If I use the layer to just have the node modules, would this be considered preloading dependencies and would make cold starts take less time?

[@guillaume5623]

really usefull, thank you

[@farooquitaha]

Thanks Sir!!

[@andrewcbuensalida]

@BiteSizeAcademy, during development on your local machine, require('/opt/utils') won't work. Would you just do require(process.env.NODE_ENV === 'production' ? '/opt/utils' : './utils') so that it automatically knows where to look for the utils folder?

[@paqliam]

so your utils file also import a node package (axios). How does it know to get that package from the nodejs folder

[@paqliam]

Actually I see captain jack comment, and I think that answers my question.

[@BiteSizeAcademy]

This video explains it in more detail: th-cam.com/video/RnFowJ130pc/w-d-xo.html (How to install npm modules in AWS Lambda?)

[@karlang2637]

At time 5:13, line 1 shows the import statement in utils.js. `const axios = require('./nodejs/node_modules/axios')`

[@kaushalendrapandey2662]

I followed the same steps but "/opt/secrets" is showing "Error: Cannot find module '/opt/secret'\

[@hgiangphan]

Silly question: Why using variable type "var" in "var sizeOf" and not "const"?

[@lautarovaleiras3623]

awesome

[@peterlau2076]

my life saver

[@sdbyrd56]

This would be better if you actually demonstrated calling a layer function from the index file. It's unclear from this that you don't have to add any directory structure; you just refer to the module as you would in a non-layered lambda function, but based on this video I tried prefixing 'opt' and then 'nodejs/node_modules', etc. until I realized you don't have to do anythingl.