Sending commands to DISCOS

The DISCOSClient provides a simple interface to send remote commands to the telescope control software.

Command interface

If the client is correctly authenticated, it exposes a command() method. This method allows you to send a command name along with any required arguments.

To send a simple command:

>>> answer = SRT.command("setupKKG")
>>> print(answer)
{'executed': True, 'command': 'setupKKG'}

To send a command with arguments:

>>> answer = SRT.command("goTo", 180, 45)
>>> print(answer)
{'executed': True, 'command': 'goTo'}

Client authentication

In order for a client to be able to send commands to DISCOS, it has to authenticate itself to the server. The authentication mechanism uses CurveZMQ, an authentication and encryption protocol for ZeroMQ based on secure elliptic-curve cryptography. The DISCOSClient package comes with an utility script capable of generating a pair of CurveZMQ keys and store them in the default DISCOSClient configuration directory.

How to generate the keys

The generation process: 1. Creates a configuration directory in the standard user path. 2. Generates a public key (identity.key) and a secret key (identity.key_secret). 3. Sets appropriate file permissions (644 for public, 600 for secret) on POSIX systems.

Usage

You can run the generator from your terminal:

discos-keygen [options]

  • --overwrite: Replace existing keys.

  • --show-only: Prints the current public key and its path without generating new ones.

Warning

Never share your secret key! Only the identity.key file should be shared. The identity.key_secret file must remain private.

Authorization Process

To be authorized to send commands to any of the telescopes:

  1. Generate your keys with discos-keygen.

  2. Locate your identity.key file.

  3. Send a copy of the identity.key file to the DISCOS team, asking for authorization for the desired telescopes. Your request will be reviewed and you will hear back from the team.

Server public key selection

To send commands, the client must know the public key of the RPC server.

For telescope-specific clients, or when using DISCOSClient with the telescope parameter, the default server public key bundled with the package is used.

If needed, this default can be overridden by passing server_public_key_file to DISCOSClient. This is especially useful for development environments, local simulators, or custom deployments using a different server key.