From 308511a7a37c40654cbbd166fc932d14969f7899 Mon Sep 17 00:00:00 2001
From: Newnius <newnius.cn@gmail.com>
Date: Mon, 18 Feb 2019 15:14:12 +0800
Subject: [PATCH] add port forwarder

---
 port-forward/Dockerfile | 13 +++++++++++++
 port-forward/README.md  | 29 +++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 port-forward/Dockerfile
 create mode 100644 port-forward/README.md

diff --git a/port-forward/Dockerfile b/port-forward/Dockerfile
new file mode 100644
index 0000000..ad87135
--- /dev/null
+++ b/port-forward/Dockerfile
@@ -0,0 +1,13 @@
+FROM alpine:3.8
+
+MAINTAINER Newnius <docker@newnius.com>
+
+ARG DEF_REMOTE_PORT=80
+ARG DEF_LOCAL_PORT=80
+
+ENV REMOTE_PORT=$DEF_REMOTE_PORT
+ENV LOCAL_PORT=$DEF_LOCAL_PORT
+
+RUN apk add --no-cache socat
+
+CMD socat tcp-listen:$LOCAL_PORT,reuseaddr,fork tcp:$REMOTE_HOST:$REMOTE_PORT
diff --git a/port-forward/README.md b/port-forward/README.md
new file mode 100644
index 0000000..b00a62b
--- /dev/null
+++ b/port-forward/README.md
@@ -0,0 +1,29 @@
+port-forward
+==========================
+Forward your traffic behind NAT, expose certain services in containers etc.
+
+## Usage
+
+Define the following environment variables to configure port-forwarding.
+
+Variable | Description | Optional
+-------- | ----------- | --------
+REMOTE_HOST | IP or address of the host you want to forward traffic to | no
+REMOTE_PORT | Port on remote host to forward traffic to | yes (80)
+LOCAL_PORT | Port where container listens | yes (80)
+
+The `socat` process within the container will listen by default to port 80, use `-p`docker
+flag to map the port of the local machine where it will listen to traffic to be forwarded.
+
+
+```bash
+docker run \
+	--name port-forward \
+	-d \
+	--restart always \
+	--publish 81:80 \
+	--ENV REMOTE_HOST=example.com \
+	--ENV REMOTE_PORT=82 \
+	--ENV LOCAL_POST=80 \
+	newnius/port-forward
+```