simple AWS Lambda -> Firehose -> JSON record -> S3

index.js

import { FirehoseClient, PutRecordCommand } from "@aws-sdk/client-firehose"

const streamName = process.env.AWS_FIREHOSE_LOG_EVENT_STREAM

const client = new FirehoseClient({})

export const logEvent = (type: string, data: Object) => {
  try {
    const record = Buffer.from(
      JSON.stringify({
        ts: Math.floor(Date.now() / 1000),
        type,
        data,
      }) + "\n"
    )

    if (!streamName) {
      console.log(`Not logging event:`, record)
      return
    }

    setImmediate(async () => {
      try {
        await client.send(
          new PutRecordCommand({
            DeliveryStreamName: streamName,
            Record: { Data: record },
          })
        )
      } catch (err) {
        console.error(`Error: Failed to log event: ${err}`)
        console.error(`Not logging event:`, record)
      }
    })
  } catch (err) {
    console.error(`Error while logging event: ${err.stack || err}`)
    console.error(`Not logging event:`, data)
  }
}