containers.c

// Unless explicitly stated otherwise all files in this repository are licensed
// under the Apache License Version 2.0.
// This product includes software developed at Datadog (https://www.datadoghq.com/).
// Copyright 2019-present Datadog, Inc.
#include "containers.h"

#include <stringutils.h>

// these must be set by the Agent
static cb_is_excluded_t cb_is_excluded = NULL;

// forward declarations
static PyObject *is_excluded(PyObject *self, PyObject *args);

static PyMethodDef methods[] = {
    { "is_excluded", (PyCFunction)is_excluded, METH_VARARGS,
      "Returns whether a container is excluded per name, image and namespace." },
    { NULL, NULL } // guards
};

#ifdef DATADOG_AGENT_THREE
static struct PyModuleDef module_def = { PyModuleDef_HEAD_INIT, CONTAINERS_MODULE_NAME, NULL, -1, methods };

PyMODINIT_FUNC PyInit_containers(void)
{
    return PyModule_Create(&module_def);
}
#elif defined(DATADOG_AGENT_TWO)
// in Python2 keep the object alive for the program lifetime
static PyObject *module;

void Py2_init_containers()
{
    module = Py_InitModule(CONTAINERS_MODULE_NAME, methods);
}
#endif

void _set_is_excluded_cb(cb_is_excluded_t cb)
{
    cb_is_excluded = cb;
}

/*! \fn PyObject *is_excluded(PyObject *self, PyObject *args)
    \brief Method to determine whether a container is excluded from metric
    collection or not.
    \param self A PyObject* pointer to the containers module.
    \param args A PyObject* pointer to the python args, typically expected to
    contain the container name, the image name and an optional namespace as strings.
    \return a PyObject * pointer, typically a boolean reflecting if the container
    should be excluded and None, if the callback has not been defined.

    This method will let us know if a container is excluded and calls the cgo-bound
    cb_is_excluded callback. The cgo callback is not expected to have any memory side
    effects and so no additional cleanup is necessary after invoking it.
*/
PyObject *is_excluded(PyObject *self, PyObject *args)
{
    // callback must be set
    if (cb_is_excluded == NULL) {
        Py_RETURN_NONE;
    }

    char *name;
    char *image;
    char *namespace = NULL;
    if (!PyArg_ParseTuple(args, "ss|s", &name, &image, &namespace)) {
        return NULL;
    }

    int result = cb_is_excluded(name, image, namespace);

    if (result > 0) {
        Py_RETURN_TRUE;
    }
    Py_RETURN_FALSE;
}