PSI_K API

This project presents a REST-HTTP API to PSI_K, a portable batch job submission interface.

To setup and run:

1. Install the rc shell and psik_api (from the site you intend to use):

     module load python/3
     python3 -m venv
     getrc.sh venv # https://github.com/frobnitzem/rcrc
     VIRTUAL_ENV=/full/path/to/venv
     PATH=$VIRTUAL_ENV/bin:$PATH
   
     pip install git+https://github.com/frobnitzem/psik_api.git

2. Setup a psik_api config file. This file is a key-value store mapping machine names to psik config files -- one for each scheduler configuration.

   Be careful with the psik_path and rc_path options here. These paths must be accessible during the execution of the job, and on the host running psik_api.

   Note that the PSIK_CONFIG environment variable does not influence the server running psik_api.

   Create a config file at $PSIK_API_CONFIG (defaults to $VIRTUAL_ENV/etc/psik_api.json) like,

   { "backends": {
       "default": {
         "prefix": "/tmp/psik_jobs",
         "backend": { "type": "local"}
       }
     }
   }
   

   or

   { "backends": {
       "default": {
         "prefix": "/ccs/proj/prj123/uname/frontier",
         "psik_path": "/ccs/proj/prj123/uname/frontier/bin/psik",
         "rc_path": "/ccs/proj/prj123/uname/frontier/bin/rc",
         "backend": {
           "type": "slurm",
           "project_name": "prj123",
           "attributes": {
           "---gpu-bind": "closest"
           }
         }
       }
     }
   }
   

3. Start the server. This can be done either directly by ssh-tunneling to a login node, or indirectly by starting a long-running containerized service.

   The ssh-tunnel method is simplest,

    ssh frontier -L 127.0.0.1:8000:/ccs/home/uname/psik_api.sock
    activate /ccs/proj/prj123/frontier
    uvicorn psik_api.main:app --log-level info --uds $HOME/psik_api.sock

Note that using a UNIX socket in `$HOME` is secure as long as
only your user can read/write from it.

For a more secure environment, use the `certified` package with:

    ssh frontier -L 8000:localhost:4433
    activate /ccs/proj/prj123/frontier
    certified serve psik_api.main:app https://127.0.0.1:4433

`certified` is a dependency of psik_api, so should already
be available if you have installed psik.

4. Browse / access the API at:

   http://127.0.0.1:8000/

5. Send a test job:

    curl -X POST \
      http://127.0.0.1:8000/v1/jobs \
      -H 'accept: application/json' \
      -H 'Content-Type: application/json' \
      -d '{
      "name": "show system info",
      "script": "cat /proc/cpuinfo; cat /proc/meminfo; rocm-smi; echo $nodes; $mpirun hostname",
      "resources": {
        "process_count": 8,
        "cpu_cores_per_process": 7,
        "duration": 2,
        "gpu_cores_per_process": 1
      }
    }'

    curl -X GET \
      'http://127.0.0.1:8000/v1/jobs \
      -H 'accept: application/json'

    # replace 1693992878.203 with your job's jobid
    curl -X GET \
      'http://127.0.0.1:8000/v1/jobs/1693992878.203/logs' \
      -H 'accept: application/json'

6. Create a job without submitting it, then send input files, then submit

    # full JobSpec must be present at this point,
    # but it will not run until later
    curl -X POST \
      http://127.0.0.1:8000/v1/jobs/new \
      -H 'accept: application/json' \
      -H 'Content-Type: application/json' \
      -d '{
      "script": "cat data.txt",
    }'

    # replace 1693992878.203 with your job's jobid below
    # Upload files
    curl -X POST \
      'http://127.0.0.1:8000/v1/jobs/1693992878.203/files/ \
      -H 'accept: application/json' \
      --upload-file data.txt

    # start the job
    curl -X POST \
      'http://127.0.0.1:8000/v1/jobs/1693992878.203/start' \
      -H 'accept: application/json'

Authorization and Authentication

The server has 3 modes of operation:

1. local -- when specifically requested with configuration setting "authz"="local". In this mode, only requests originating from the localhost IP (either v4 or v6) will be served. Also, this mode is the only way to serve the full API through a UNIX domain socket.

2. insecure -- when Request.transport is not available (started without certified serve). In this case the user name is taken as 'addr:' -- based on the client's address. Psik_api will refuse to issue tokens (hence no access to secured routes) in this case.

3. TLS -- when started with certified serve

In local mode, the system sees all jobs as owned by user local:psik_api.

In TLS mode, the user value is read from a biscuit token that the client provides on each request. This should be present in a header like, Authorization: bearer b64-encoded-biscuit-value=. If no biscuit is provided with the request, then one is auto-generated for that request by reading the client's TLS certificate.

Note, a biscuit can also be generated with user == client by visiting the /token endpoint.

A database tracks the owner of each job and grants GET/POST permissions only to a job's owner. This way, a user can delegate access permissions to a job to another user or an automated agent.

Note that biscuits allow tokens to be attenuated by enforcing additional checks. For example, by checking mode=GET, they can confer a token that grants read-only access.

Sites may customize the job access policy above by implementing a custom authz class -- replacing psik_api.authz:BaseAuthz in their Config.authz setting.