ssh-tail

This project is one of the problems that I generally face while debugging some system. When I am reproducing the issue on the machine i also want to tail the logs side-by-side to see the error. This becomes cumbersome when i need to fetch multiple log files or use them for future purpose or constantly hop between dashboards, script and machine for the session.

To solve this comes ssh-tail. It is a binary to tail log files from remote ssh machines and store them locally into your system for debugging or storage purpose. It is controlled by a JSON config which saves me time of creating multiple ssh-session either using a window managers or some bash script which does that for me. Logic for creating new filenames based on the unique flag.

It assumes that you have an unecrypted private key and present in your home folder inside an .ssh folder and ssh-agent is running on your machine.

To use ssh-tail you need to set and env variable while running the process SSH_TAIL_CONFIG which will pick the json config to use for the ssh session.

Sinks

Sinks are the interfaces which will be used to dump the data fetched from the ssh session running on the remote machine. These sinks can be local file system or an external service like S3. For now the implementation is only made for the local file system but later S3 or any plugin can be included.

Usage

SSH_TAIL_CONFIG="ssh_tunnel.json" make

Example cofig file:

{
  "host": "machine_ip",
  "port": int_port_number,
  "username": "username",
  "commands": [
    {
      "command": "command_1",
      "file": "file_1"
    },
    {
      "command": "command_2",
      "file": "file_2"
    }
    ...
  ]
}

For use with machines that are behind a proxy:

{
  "host": "target_machine_ip",
  "port": target_machine_port,
  "username": "username",
  "proxyConfig": {
    "host": "proxy_machine_ip / hop_ip",
    "port": proxy_jump_machine_port,
    "username": "proxy_jump_username"
  },
  "commands": [
    {
      "command": "command_1",
      "file": file_1
    }
    ...
  ]
}

Building locally

You can build the binary locally using the following command.

make build

This will generate build files for targets (windows, linux and darwin).

Development / Contribution

This is just a binary that i created for myself to ease my workflow. In case you also face similar issues or want to solve some existing issue, feel free to dive right in and send a patch my way. I would be happy to review your patch.

To test out the changes locally you can use the following command.

SSH_TAIL_CONFIG="ssh_tunnel.json" make