Serverless MongoDB Docker Lambda Import/Export Sync

bootstrap.sh

#!/bin/sh

set -euo pipefail

# Initialization - load function handler
source $LAMBDA_TASK_ROOT/"$(echo $_HANDLER | cut -d. -f1).sh"

# Processing
while true
do
  HEADERS="$(mktemp)"
  # Get an event. The HTTP request will block until one is received
  EVENT_DATA=$(curl -s --show-error -LD "$HEADERS" -X GET "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/next")

  # Extract request ID by scraping response headers received above
  REQUEST_ID=$(grep -Fi Lambda-Runtime-Aws-Request-Id "$HEADERS" | tr -d '[:space:]' | cut -d: -f2)

  # Run the handler function from the script
  RESPONSE=$($(echo "$_HANDLER" | cut -d. -f2) "$EVENT_DATA")

  # Send the response
  curl -s --show-error -X POST "http://${AWS_LAMBDA_RUNTIME_API}/2018-06-01/runtime/invocation/$REQUEST_ID/response" -d "$RESPONSE"
done

Dockerfile

# Ref: https://gallery.ecr.aws/lambda/provided
# + https://docs.aws.amazon.com/lambda/latest/dg/runtimes-images.html
# + https://aws.amazon.com/blogs/aws/new-for-aws-lambda-container-image-support/
FROM public.ecr.aws/lambda/provided:al2

COPY bootstrap.sh ${LAMBDA_RUNTIME_DIR}/bootstrap
COPY function.sh ${LAMBDA_TASK_ROOT}

# Ref https://www.mongodb.com/docs/v6.0/tutorial/install-mongodb-on-amazon/
SHELL ["/bin/bash", "-c"]
RUN echo $'[mongodb-org-6.0] \n\
name=MongoDB Repository \n\
baseurl=https://repo.mongodb.org/yum/amazon/2/mongodb-org/6.0/x86_64/ \n\
gpgcheck=1 \n\
enabled=1 \n\
gpgkey=https://www.mongodb.org/static/pgp/server-6.0.asc \n\
' > /etc/yum.repos.d/mongodb-org-6.0.repo
RUN yum install -y mongodb-mongosh mongodb-org-tools

CMD ["function.handler"]

function.sh

#!/bin/sh

function export_import_collections() {
  for collection_name in ${collection_names}
  do
    file="/tmp/${collection_name}.json"
    echo "Exporting ${source_database_name}.${collection_name} to ${file}..."
    mongoexport --db "${source_database_name}" --collection "${collection_name}" --uri "${source_connection_url}" --out $file
    ls -lah "${file}"
    echo "Importing from file ${file} to ${target_database_name}.${collection_name}..."
    mongoimport --db "${target_database_name}" --collection "${collection_name}" --mode "upsert" --uri "${target_connection_url}" --file $file
    echo "Finished collection ${collection_name}."
  done
}

function handler () {
  EVENT_DATA=$1
  echo "$EVENT_DATA" 1>&2;

  export_import_collections

  RESPONSE="Success!"

  echo $RESPONSE
}

serverless.yml

# Ref: https://www.serverless.com/framework/docs/providers/aws/guide/serverless.yml
# + https://www.serverless.com/blog/container-support-for-lambda
service: serverless-docker
frameworkVersion: '3'

provider:
  name: aws
  stage: prod
  region: eu-west-1
#  architecture: arm64
  ecr:
    images:
      some-image:
        path: ./some-image

functions:
  some-function:
    events: # 5 minutes past midnight UTC every day
      - schedule: cron(05 00 * * ? *)
    environment:
      source_connection_url: "mongodb://source"
      source_database_name: "sourceDb"
      collection_names: "col1 col2"
      target_connection_url: "mongodb://target"
      target_database_name: "targetDb"
    image:
      name: some-image