lmcache--lmcache/docs/source/internal_api_server/common_apis.rst

.. _common_apis:

Common APIs
===========

.. warning::

   This page documents the behavior of LMCache's in-process mode (deprecated). Please consider using :doc:`LMCache MP mode </mp/index>` for better feature support and performance. For the MP mode equivalent of this page, see :doc:`/mp/http_api`.


Common APIs are available across all components (scheduler, worker, controller).

.. contents:: Endpoints
   :local:
   :depth: 2


``GET /env`` — Environment Variables
-------------------------------------

Get all environment variables of the running process.

- **Method**: ``GET``
- **Path**: ``/env``
- **Parameters**: None
- **Response**: ``application/json`` — JSON object of all environment variables (sorted by key).

.. code-block:: bash

    curl http://localhost:7000/env

**Example Response**:

.. code-block:: json

    {
      "HOME": "/root",
      "PATH": "/usr/local/bin:/usr/bin",
      "PYTHONPATH": "/app"
    }


``GET /loglevel`` — Log Level Management
------------------------------------------

Get or set the log level for Python loggers. Behavior depends on query parameters:

- **No parameters**: List all loggers and their levels.
- **``logger_name`` only**: Get the level of the specified logger.
- **``logger_name`` and ``level``**: Set the level of the specified logger (including all its handlers).

- **Method**: ``GET``
- **Path**: ``/loglevel``
- **Parameters**:

  =============== ======== ============================================
  Name            Type     Description
  =============== ======== ============================================
  ``logger_name`` str      (Optional) Logger name to query or set
  ``level``       str      (Optional) Log level to set (e.g. ``DEBUG``, ``INFO``, ``WARNING``, ``ERROR``)
  =============== ======== ============================================

- **Response**: ``text/plain``

.. code-block:: bash

    # List all loggers
    curl http://localhost:7000/loglevel

    # Get a specific logger level
    curl "http://localhost:7000/loglevel?logger_name=lmcache.v1.cache_engine"

    # Set a specific logger level
    curl "http://localhost:7000/loglevel?logger_name=lmcache.v1.cache_engine&level=DEBUG"

**Example Response** (list all):

.. code-block:: text

    === Loggers and Levels ===
    lmcache.v1.cache_engine: WARNING
    lmcache.v1.storage_backend: INFO

**Example Response** (get):

.. code-block:: text

    lmcache.v1.cache_engine: WARNING

**Example Response** (set):

.. code-block:: text

    Set lmcache.v1.cache_engine level to DEBUG (including all handlers)

**Error Response** (invalid level, HTTP 400):

.. code-block:: text

    Invalid log level: INVALID_LEVEL


``GET /metrics`` — Prometheus Metrics
--------------------------------------

Get Prometheus metrics data in the standard exposition format.

- **Method**: ``GET``
- **Path**: ``/metrics``
- **Parameters**: None
- **Response**: ``text/plain`` — Prometheus text-based exposition format.

.. code-block:: bash

    curl http://localhost:7000/metrics


``POST /metrics/reset`` — Reset Prometheus Metrics
----------------------------------------------------

Reset all Prometheus metrics to their initial state.

- **Method**: ``POST``
- **Path**: ``/metrics/reset``
- **Parameters**: None
- **Response**: ``text/plain`` — ``"ok"`` on success.

.. code-block:: bash

    curl -X POST http://localhost:7000/metrics/reset


``GET /threads`` — Thread Information
--------------------------------------

Get information about active threads with optional filtering.

- **Method**: ``GET``
- **Path**: ``/threads``
- **Parameters**:

  ============== ======= ===========================================
  Name           Type    Description
  ============== ======= ===========================================
  ``name``       str     (Optional) Filter by thread name (fuzzy match, case-insensitive)
  ``thread_id``  int     (Optional) Filter by thread ID
  ============== ======= ===========================================

- **Response**: ``text/plain`` — Thread info with stack traces and summary.

.. code-block:: bash

    # Get all threads
    curl http://localhost:7000/threads

    # Filter by name
    curl "http://localhost:7000/threads?name=api-server"

    # Filter by thread ID
    curl "http://localhost:7000/threads?thread_id=12345"


``GET /periodic-threads`` — Periodic Thread Status
----------------------------------------------------

Get information about registered periodic threads.

- **Method**: ``GET``
- **Path**: ``/periodic-threads``
- **Parameters**:

  ================ ======= =============================================
  Name             Type    Description
  ================ ======= =============================================
  ``level``        str     (Optional) Filter by thread level: ``critical``, ``high``, ``medium``, ``low``
  ``running_only`` bool    (Optional) Only show running threads (default: ``false``)
  ``active_only``  bool    (Optional) Only show active threads (default: ``false``)
  ================ ======= =============================================

- **Response**: ``application/json``

.. code-block:: bash

    # Get all periodic threads
    curl http://localhost:7000/periodic-threads

    # Filter by level
    curl "http://localhost:7000/periodic-threads?level=critical"

    # Only running threads
    curl "http://localhost:7000/periodic-threads?running_only=true"

**Example Response**:

.. code-block:: json

    {
      "summary": {
        "total_count": 5,
        "running_count": 3,
        "active_count": 3,
        "by_level": {
          "critical": {"total": 1, "running": 1, "active": 1},
          "high": {"total": 2, "running": 1, "active": 1}
        }
      },
      "threads": [
        {
          "name": "heartbeat",
          "level": "critical",
          "is_running": true,
          "is_active": true,
          "last_run_time": "2025-01-01T00:00:00",
          "interval": 10.0
        }
      ]
    }

**Error Response** (invalid level, HTTP 400):

.. code-block:: json

    {
      "error": "Invalid level: unknown. Valid values: critical, high, medium, low"
    }


``GET /periodic-threads/{thread_name}`` — Single Periodic Thread
------------------------------------------------------------------

Get detailed information about a specific periodic thread by name.

- **Method**: ``GET``
- **Path**: ``/periodic-threads/{thread_name}``
- **Path Parameters**:

  ================ ======= =============================================
  Name             Type    Description
  ================ ======= =============================================
  ``thread_name``  str     Name of the periodic thread
  ================ ======= =============================================

- **Response**: ``application/json``

.. code-block:: bash

    curl http://localhost:7000/periodic-threads/heartbeat

**Error Response** (not found, HTTP 404):

.. code-block:: json

    {
      "error": "Thread not found: heartbeat"
    }


``GET /periodic-threads-health`` — Periodic Thread Health Check
-----------------------------------------------------------------

Quick health check for periodic threads. Returns healthy status if all
``critical`` and ``high`` level threads are active.

- **Method**: ``GET``
- **Path**: ``/periodic-threads-health``
- **Parameters**: None
- **Response**: ``application/json``

.. code-block:: bash

    curl http://localhost:7000/periodic-threads-health

**Example Response** (healthy):

.. code-block:: json

    {
      "healthy": true,
      "unhealthy_count": 0,
      "unhealthy_threads": []
    }

**Example Response** (unhealthy):

.. code-block:: json

    {
      "healthy": false,
      "unhealthy_count": 1,
      "unhealthy_threads": [
        {
          "name": "heartbeat",
          "level": "critical",
          "last_run_ago": 120.5,
          "interval": 10.0
        }
      ]
    }


``POST /run_script`` — Run Script
-----------------------------------

Upload and execute a Python script in a restricted sandbox environment.
The script has access to ``app`` (the FastAPI application instance) and
a limited set of builtins. Import is restricted to modules configured
in ``script_allowed_imports``.

- **Method**: ``POST``
- **Path**: ``/run_script``
- **Content-Type**: ``multipart/form-data``
- **Parameters**:

  ============ ======== =============================================
  Name         Type     Description
  ============ ======== =============================================
  ``script``   file     Python script file to execute
  ============ ======== =============================================

- **Response**: ``text/plain`` — The ``result`` variable from the script, or
  ``"Script executed successfully"`` if no ``result`` is set.

.. code-block:: bash

    curl -X POST http://localhost:7000/run_script \
      -F "script=@/path/to/scratch.py"

**Example Script** (``scratch.py``):

.. code-block:: python

    lmcache_engine = app.state.lmcache_adapter.lmcache_engine

    result = {
        "is_first_rank": lmcache_engine.metadata.is_first_rank(),
        "model_version": lmcache_engine.metadata.kv_shape,
    }

**Example Response**:

.. code-block:: text

    {'is_first_rank': True, 'model_version': (27, 1, 64, 1, 576)}

**Error Response** (no script, HTTP 400):

.. code-block:: text

    No script file provided

**Error Response** (execution error, HTTP 500):

.. code-block:: text

    Error executing script: Import of 'os' is not allowed