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Add post script functionality #45

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Add post script functionality #45

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15 changes: 15 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -259,6 +259,21 @@ Examples:

Additional details are available from [`ssh_config(5)`](https://linux.die.net/man/5/ssh_config)

#### SSH_POST_SCRIPT

When set, SSH_POST_SCRIPT will be the location of a shell script to execute after starting autossh.
This is useful to send some details to the server about the autossh client.
For example, if a random port is used, then it's useful for the server to know who is on this port.
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it's useful for the server to know who is on this port.

This does not make sense just reading it.

Do you mean to say you can associate a specific container/instance of autossh is using a specific port remotely? I'm a bit confused as to the usecase.

SSH_TUNNEL_PORT can be used in the post script like so:
```
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add another space, and don't forget to call out the specific language in the markdown. (e.g. '''sh, note the incorrect use of quotes because I couldn't easily figure out how to add in backticks). See line 112 of this file for an example.

FILE=/tmp/autossh.${SSH_CLIENT_ID}
echo "${SSH_TUNNEL_PORT}" > ${FILE}
scp ${FILE} ${SSH_REMOTE_USER}@${SSH_REMOTE_HOST}:/tmp
```
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add one blank line below codeblock.

In this example SSH_CLIENT_ID is set to some identifier that represents the client and the port is
set in a file. This could be useful when you have multiple client connections and you need to know
on the server which client to connect to. Mount the shell script in a docker volume.

#### Additional Environment variables

- [`autossh(1)`](https://linux.die.net/man/1/autossh)
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21 changes: 19 additions & 2 deletions rootfs/entrypoint.sh
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Expand Up @@ -62,5 +62,22 @@ COMMAND="autossh "\

echo "[INFO ] # ${COMMAND}"

# Run command
exec ${COMMAND}
# Run autossh command in background and save pid
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Please write a test for this in a new container, you may call it the local-post-script container if you'd like.

The test container should exit with 0 when you have proven the post_script ran successfully and return non-zero when the script failed to run.

exec ${COMMAND} &
pid=$!
sleep 1
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Why are we sleeping here? If we're just sleeping here to give time for the tunnel to instantiate, we should find a better way to confirm that.

Also, if that fails, we should exit() in some fashion.


# Export the Tunnel Port for post script to use
export SSH_TUNNEL_PORT=${SSH_TUNNEL_PORT}
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Is there any other interesting variables we can/should expose?


if [[ -e /proc/$pid ]] && [[ -n "${SSH_POST_SCRIPT}" ]]; then
if [[ -f "${SSH_POST_SCRIPT}" ]]; then
# Execute Post Script
echo "[INFO ] Executing ${SSH_POST_SCRIPT}"
/bin/sh "${SSH_POST_SCRIPT}"
else
echo "[WARN ] ${SSH_POST_SCRIPT} was not found"
fi
fi

wait $pid