initial commit

Dockerfile

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+FROM alpine:3.13
+
+RUN apk add --no-cache --update openssh-client
+CMD ssh \ 
+    -o StrictHostKeyChecking=no \
+    -N ${TUNNEL_HOST} \
+    -L ${FORWARD_DSN}
+

README.md

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+# SSH tunnel in Docker
+
+Use case: allow your Docker containers to use SSH tunnels
+to get into those hard to reach places like corporate resources,
+firewalled APIs etc.
+
+## Usage with Docker Compose
+
+```yaml
+services:
+    # your reglar services
+
+    ssh-tunnel:
+        image: sigwinhq/ssh-tunnel:latest
+        environment:
+            # if the key is password-protected
+            SSH_AUTH_SOCK: "/ssh-agent"
+            # the host via which we tunnel
+            TUNNEL_HOST: "[email protected]"
+            # what do we want to proxy to?
+            FORWARD_DSN: "*:443:firewalled-api.example.com:443"
+        volumes:
+            # your key is now usable by the tunnel
+            - $HOME/.ssh:/root/ssh:ro
+            # if the key is password-protected
+            - $SSH_AUTH_SOCK:/ssh-agent
+        # this part is to make the tunnel transparent to others
+        networks:
+            default:
+                aliases:
+                    - firewalled-api.example.com
+```
+
+After doing this, your other services should now have access
+to the firewalled API as if it's available directly,
+without even knowing about the proxy.