Add s3cmd scheduling for automatic backup

s3cmd/Dockerfile

@@ -1,9 +1,13 @@
-FROM alpine:3.1
+FROM alpine:3.7
 LABEL maintainer="Johannes Schickling <schickling.j@gmail.com>"
 
 ADD install.sh install.sh
 RUN sh install.sh && rm install.sh
 
+ENV SCHEDULE **None**
+
+ADD run.sh /opt/s3cmd/run.sh
+
 WORKDIR /s3
 
-ENTRYPOINT ["s3cmd"]
+ENTRYPOINT ["/opt/s3cmd/run.sh"]

s3cmd/README.md

@@ -1,12 +1,21 @@
 # s3cmd
 Lightweight wrapper around s3cmd
 
-## Usage
+## Basic usage
 
 ```sh
 $ docker run -v $(pwd):/s3 schickling/s3cmd sync . s3://my-bucket
 ```
 
+## Environment variables
+
+- SCHEDULE backup schedule time, see explainatons below
+
+## Automatic Periodic Backups
+
+You can additionally set the SCHEDULE environment variable like -e SCHEDULE="@daily" to run the backup automatically.
+More information about the scheduling can be found [here](http://godoc.org/github.com/robfig/cron#hdr-Predefined_schedules).
+
 ### `s3cmd` documentation
 
 See [here](http://s3tools.org/usage) for the documentation.

s3cmd/install.sh

@@ -5,12 +5,16 @@ set -e
 
 # install s3cmd
 apk update
-apk add python py-pip py-setuptools git ca-certificates
+apk add --no-cache python py-pip py-setuptools git ca-certificates
 pip install python-magic
 git clone https://github.com/s3tools/s3cmd.git /tmp/s3cmd
 cd /tmp/s3cmd
 python setup.py install
-
-# cleanup
 apk del git
-rm -rf /var/cache/apk/* /tmp/s3cmd
+rm -rf /tmp/s3cmd
+
+# install go-cron
+apk add --no-cache curl
+curl -L --insecure https://github.com/odise/go-cron/releases/download/v0.0.6/go-cron-linux.gz | zcat > /usr/local/bin/go-cron
+chmod u+x /usr/local/bin/go-cron
+apk del curl

s3cmd/run.sh

@@ -0,0 +1,11 @@
+#! /bin/sh
+
+set -e
+
+echo "Running s3cmd ..."
+
+if [ "${SCHEDULE}" = "**None**" ]; then
+  s3cmd "$@"
+else
+  exec go-cron "$SCHEDULE" s3cmd "$@"
+fi