Lambda Layers not installing with Serverless - aws-lambda

Question

Currently getting the following error with MongoDB:
no saslprep library specified. Passwords will not be sanitized
We are using Webpack so simply installing the module doesn't work (Webpack just ignores it). I found this thread which talks about how to exclude it from Webpack compilations, but then I have to manually load it into every Lambda function which led me to Lambda Layers.
Following the Serverless guide on using Lambda layers allowed me to get my layer published to AWS and included in all of my functions, but for some reason, it doesn't install the modules. If I download the layer using the AWS GUI, I get a folder with just the package.json and package-lock.json files.
My file structure is:
my-project
|_ layers
|_ saslprep
|_ package.json
and my serverless.yml is:
layers:
saslprep:
path: layers/saslprep
compatibleRuntimes:
- nodejs14.x

Answer 1

This is not my preferred solution as I'd like to use 256, but the way I got around this error/warning was by changing the authMechanism from SCRAM-SHA-256 to SCRAM-SHA-1 in the connection string. The serverless-bundle most likely needs to add this dependency into their package to enable support for Mongo 4.0 SHA256 (my best guess!).
You can specify this authentication mechanism by setting the authMechanism parameter to the value SCRAM-SHA-1 in the connection string as shown in the following sample code.
const { MongoClient } = require("mongodb");
// Replace the following with values for your environment.
const username = encodeURIComponent("<username>");
const password = encodeURIComponent("<password>");
const clusterUrl = "<MongoDB cluster url>";
const authMechanism = "SCRAM-SHA-1";
// Replace the following with your MongoDB deployment's connection string.
const uri =
`mongodb+srv://${username}:${password}#${clusterUrl}/?authMechanism=${authMechanism}`;
// Create a new MongoClient
const client = new MongoClient(uri);
// Function to connect to the server
async function run() {
try {
// Connect the client to the server
await client.connect();
// Establish and verify connection
await client.db("admin").command({ ping: 1 });
console.log("Connected successfully to server");
} finally {
// Ensures that the client will close when you finish/error
await client.close();
}
}
run().catch(console.dir);