From 09ba3b4d1dfb0cdac716aadd6865fb2df06f50a6 Mon Sep 17 00:00:00 2001
From: Alin Voinea <alin@eaudeweb.ro>
Date: Fri, 8 Apr 2016 17:15:46 +0300
Subject: [PATCH] Refs #71087 - Add rsync server/client support

---
 Dockerfile           |  5 ++++
 Readme.md            | 49 ++++++++++++++++++++++++++++---
 docker-entrypoint.sh | 68 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 118 insertions(+), 4 deletions(-)
 create mode 100755 docker-entrypoint.sh

diff --git a/Dockerfile b/Dockerfile
index 63e036d..6fd5624 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,3 +2,8 @@ FROM alpine:3.3
 MAINTAINER "EEA: IDM2 A-Team" <eea-edw-a-team-alerts@googlegroups.com>
 
 RUN apk add --no-cache --virtual .run-deps rsync openssh
+COPY docker-entrypoint.sh /
+
+VOLUME /root
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["sh"]
diff --git a/Readme.md b/Readme.md
index 9cd5a0f..a02f439 100644
--- a/Readme.md
+++ b/Readme.md
@@ -1,8 +1,49 @@
 # Simple rsync container based on alpine
 
-A simple rsync Docker image to easily rsync data within Docker volumes
+A simple rsync server/client Docker image to easily rsync data within Docker volumes
 
-## Usage
+## Simple Usage
 
-    $ docker run -it --rm -v blobstorage:/data/ eeacms/rsync \
-             rsync user@remote.server.domain.or.ip:/var/local/blobs/ /data/
+Get files from remote server within a `docker volume`:
+
+    $ docker run --rm -v blobstorage:/data/ eeacms/rsync \
+                 rsync -avz user@remote.server.domain.or.ip:/var/local/blobs/ /data/
+
+Get files from `remote server` to a `data container`:
+
+    $ docker run -d --name data -v /data busybox
+    $ docker run --rm --volumes-from=data eeacms/rsync \
+             rsync -avz user@remote.server.domain.or.ip:/var/local/blobs/ /data/
+
+## Advanced Usage
+
+### Client setup
+
+Start client to sync every night at 3AM:
+
+    $ docker run --name=rsync_client -v client_vol_to_sync:/data \
+                 -e CRON_TASK="0 3 * * * rsync -e 'ssh -p 2222 -o StrictHostKeyChecking=no' -avz root@foo.bar.com:/data/ /data/" \
+             eeacms/rsync client
+
+Copy the client SSH public key printed found in console
+
+### Server setup
+
+Start server on `foo.bar.com`
+
+    # docker run --name=rsync_server -d -p 2222:22 -v server_vol_to_sync:/data \
+                 -e SSH_AUTH_KEY="<SSH KEY FROM rsync_client>" \
+             eeacms/rsync server
+
+### Verify that it works
+
+Add `test` file on server:
+
+    $ docker exec -it rsync_server sh
+      $ touch /data/test
+
+Bring the `file` on client:
+
+    $ docker exec -it rsync_client sh
+      $ rsync -e 'ssh -p 2222 -o StrictHostKeyChecking=no' -avz root@foo.bar.com:/data/ /data/
+      $ ls -l /data/
diff --git a/docker-entrypoint.sh b/docker-entrypoint.sh
new file mode 100755
index 0000000..5749260
--- /dev/null
+++ b/docker-entrypoint.sh
@@ -0,0 +1,68 @@
+#!/bin/sh
+
+################################################################################
+# INIT
+################################################################################
+
+# Provide SSH AUTHORIZED KEY via environment variable
+if [ ! -z "$SSH_AUTH_KEY" ]; then
+  mkdir -p /root/.ssh
+  echo "$SSH_AUTH_KEY" > /root/.ssh/authorized_keys
+  chmod go-rwx /root/.ssh/authorized_keys
+  sed -i "s/#PasswordAuthentication yes/PasswordAuthentication no/g" /etc/ssh/sshd_config
+fi
+
+# Provide CRON_TASK via environment variable
+if [ ! -z "$CRON_TASK" ]; then
+  echo "$CRON_TASK" > /etc/crontabs/root
+  echo "root" > /etc/crontabs/cron.update
+fi
+
+# Generate host SSH keys
+if [ ! -e /etc/ssh/ssh_host_rsa_key.pub ]; then
+  ssh-keygen -A
+fi
+
+# Generate root SSH key
+if [ ! -e /root/.ssh/id_rsa.pub ]; then
+  ssh-keygen -q -N "" -f /root/.ssh/id_rsa
+fi
+
+################################################################################
+# START as SERVER
+################################################################################
+
+if [ "$1" == "server" ]; then
+  AUTH=`cat /root/.ssh/authorized_keys`
+  if [ -z "$AUTH" ]; then
+    echo "=================================================================================="
+    echo "ERROR: No SSH_AUTH_KEY provided, you'll not be able to connect to this container. "
+    echo "=================================================================================="
+    exit 1
+  fi
+
+  SSH_PARAMS="-D -e -p ${SSH_PORT:-22} $SSH_PARAMS"
+  echo "================================================================================"
+  echo "Running: /usr/sbin/sshd $SSH_PARAMS                                             "
+  echo "================================================================================"
+
+  exec /usr/sbin/sshd -D $SSH_PARAMS
+fi
+
+echo "Please add this ssh key to your server /home/user/.ssh/authorized_keys        "
+echo "================================================================================"
+echo "`cat /root/.ssh/id_rsa.pub`"
+echo "================================================================================"
+
+################################################################################
+# START as CLIENT via crontab
+################################################################################
+
+if [ "$1" == "client" ]; then
+  exec /usr/sbin/crond -f
+fi
+
+################################################################################
+# Anything else
+################################################################################
+exec "$@"