made AWS credentials optional

Dockerfile

@@ -1,6 +1,6 @@
 FROM ubuntu:18.04
 
-RUN apt-get update && apt-get install -y --no-install-recommends curl cron awscli
+RUN apt-get update && apt-get install -y --no-install-recommends curl cron awscli less vim
 RUN rm -rf /var/lib/apt/lists/*
 
 # https://docs.docker.com/engine/installation/linux/docker-ce/ubuntu/#install-using-the-convenience-script

README.md

@@ -149,8 +149,8 @@ Variable | Default | Notes
 `BACKUP_WAIT_SECONDS` | `0` | The backup script will sleep this many seconds between re-starting stopped containers, and proceeding with archiving/uploading the backup. This can be useful if you don't want the load/network spike of a large upload immediately after the load/network spike of container startup.
 `BACKUP_HOSTNAME` | `$(hostname)` | Name of the host (i.e. Docker container) in which the backup runs. Mostly useful if you want a specific hostname to be associated with backup metrics (see InfluxDB support).
 `AWS_S3_BUCKET_NAME` |  | When provided, the resulting backup file will be uploaded to this S3 bucket after the backup has ran.
-`AWS_ACCESS_KEY_ID` |  | Required when using `AWS_S3_BUCKET_NAME`.
-`AWS_SECRET_ACCESS_KEY` |  | Required when using `AWS_S3_BUCKET_NAME`.
+`AWS_ACCESS_KEY_ID` |  | Optional when using `AWS_S3_BUCKET_NAME`. Allows you to provide credentials for AWS authentication.
+`AWS_SECRET_ACCESS_KEY` |  | Optional when using `AWS_S3_BUCKET_NAME`. Allows you to provide credentials for AWS authentication.
 `AWS_DEFAULT_REGION` |  | Optional when using `AWS_S3_BUCKET_NAME`. Allows you to override the AWS CLI default region. Usually not needed.
 `INFLUXDB_URL` |  | When provided, backup metrics will be sent to an InfluxDB instance at this URL, e.g. `https://influxdb.example.com`.
 `INFLUXDB_DB` |  | Required when using `INFLUXDB_URL`; e.g. `my_database`.

src/entrypoint.sh

@@ -8,7 +8,7 @@ cat <<EOF > env.sh
 BACKUP_SOURCES="${BACKUP_SOURCES:-/backup}"
 BACKUP_CRON_EXPRESSION="${BACKUP_CRON_EXPRESSION:-@daily}"
 AWS_S3_BUCKET_NAME="${AWS_S3_BUCKET_NAME:-}"
-BACKUP_FILENAME="$(date +"${BACKUP_FILENAME:-backup-%Y-%m-%dT%H-%M-%S.tar.gz}")"
+BACKUP_FILENAME="\$(date +"${BACKUP_FILENAME:-backup-%Y-%m-%dT%H-%M-%S.tar.gz}")"
 BACKUP_ARCHIVE="${BACKUP_ARCHIVE:-/archive}"
 BACKUP_WAIT_SECONDS="${BACKUP_WAIT_SECONDS:-0}"
 BACKUP_HOSTNAME="${BACKUP_HOSTNAME:-$(hostname)}"
@@ -22,11 +22,13 @@ source env.sh
 
 # Configure AWS CLI
 mkdir -p .aws
+if [ ! -z "$AWS_ACCESS_KEY_ID" ]; then
 cat <<EOF > .aws/credentials
 [default]
 aws_access_key_id = ${AWS_ACCESS_KEY_ID}
 aws_secret_access_key = ${AWS_SECRET_ACCESS_KEY}
 EOF
+fi
 if [ ! -z "$AWS_DEFAULT_REGION" ]; then
 cat <<EOF > .aws/config
 [default]
@@ -37,6 +39,11 @@ fi
 # Add our cron entry, and direct stdout & stderr to Docker commands stdout
 echo "Installing cron.d entry: docker-volume-backup"
 echo "$BACKUP_CRON_EXPRESSION root /root/backup.sh > /proc/1/fd/1 2>&1" > /etc/cron.d/docker-volume-backup
+echo -e "\n" >> /etc/cron.d/docker-volume-backup
+
+# Remove line from PAM config because cron won't run otherwise on AWS EC2 Linux
+echo "Editing /etc/pam.d/cron"
+sed -i '/session    required     pam_loginuid.so/c\#session    required   pam_loginuid.so' /etc/pam.d/cron
 
 # Let cron take the wheel
 echo "Starting cron in foreground with expression: $BACKUP_CRON_EXPRESSION"