🗄️ Back up a postgres database running inside a docker container to S3

backup.sh

#!/bin/bash

set -e
set -o pipefail

GENERATION_DATE=$(date -u +"%Y-%m-%dT%H-%M-%SZ")
GENERATED_BACKUP_FILE="backup-$GENERATION_DATE.dump"

if [ -e .env ]; then
  read -ra env < <(xargs < .env)
  export "${env[@]}"
fi

[[ -z "$DATABASE_CONTAINER" ]] && { errecho "DATABASE_CONTAINER is empty" ; exit 1; }
[[ -z "$DATABASE_URL" ]] && { errecho "DATABASE_URL is empty" ; exit 1; }
[[ -z "$AWS_ACCESS_KEY_ID" ]] && { errecho "AWS_ACCESS_KEY_ID is empty" ; exit 1; }
[[ -z "$AWS_SECRET_ACCESS_KEY" ]] && { errecho "AWS_SECRET_ACCESS_KEY is empty" ; exit 1; }
[[ -z "$AWS_DEFAULT_REGION" ]] && { errecho "AWS_DEFAULT_REGION is empty" ; exit 1; }
[[ -z "$AWS_BUCKET_NAME" ]] && { errecho "AWS_BUCKET_NAME is empty" ; exit 1; }
[[ -z "$AWS_BACKUP_FOLDER" ]] && { errecho "AWS_BACKUP_FOLDER is empty" ; exit 1; }

docker exec "$DATABASE_CONTAINER" pg_dump -Fc --dbname="$DATABASE_URL" |
  gzip - --best |
  docker run \
    --rm -i \
    --env AWS_ACCESS_KEY_ID \
    --env AWS_SECRET_ACCESS_KEY \
    --env AWS_DEFAULT_REGION \
    amazon/aws-cli s3 cp - "s3://$AWS_BUCKET_NAME/$AWS_BACKUP_FOLDER/$GENERATED_BACKUP_FILE.gz"

You might want to use this along with crontab and s3 expiration policies. Also don't forget to add in an .env file or pass them in explicitly.