src/python.c

   1 #include <Python.h>
   2 #include <structmember.h>
   3
   4 #include "collectd.h"
   5 #include "common.h"
   6
   7 #include "cpython.h"
   8
   9 typedef struct cpy_callback_s {
  10         char *name;
  11         PyObject *callback;
  12         PyObject *data;
  13         struct cpy_callback_s *next;
  14 } cpy_callback_t;
  15
  16 /* This is our global thread state. Python saves some stuff in thread-local
  17  * storage. So if we allow the interpreter to run in the background
  18  * (the scriptwriters might have created some threads from python), we have
  19  * to save the state so we can resume it later after shutdown. */
  20
  21 static PyThreadState *state;
  22
  23 static cpy_callback_t *cpy_config_callbacks;
  24 static cpy_callback_t *cpy_init_callbacks;
  25 static cpy_callback_t *cpy_shutdown_callbacks;
  26
  27 static void cpy_destroy_user_data(void *data) {
  28         cpy_callback_t *c = data;
  29         free(c->name);
  30         Py_DECREF(c->callback);
  31         Py_XDECREF(c->data);
  32         free(c);
  33 }
  34
  35 /* You must hold the GIL to call this function!
  36  * But if you managed to extract the callback parameter then you probably already do. */
  37
  38 static void cpy_build_name(char *buf, size_t size, PyObject *callback, const char *name) {
  39         const char *module;
  40         PyObject *mod = NULL, *n = NULL;
  41
  42         if (name != NULL && strchr(name, '.') != NULL) {
  43                 snprintf(buf, size, "python.%s", name);
  44                 return;
  45         }
  46
  47         mod = PyObject_GetAttrString(callback, "__module__"); /* New reference. */
  48         if (mod != NULL)
  49                 module = PyString_AsString(mod);
  50         else
  51                 module = "collectd";
  52         if (name != NULL) {
  53                 snprintf(buf, size, "python.%s.%s", module, name);
  54                 Py_XDECREF(mod);
  55                 return;
  56         }
  57
  58         n = PyObject_GetAttrString(callback, "__name__"); /* New reference. */
  59         if (n != NULL)
  60                 name = PyString_AsString(n);
  61
  62         if (name != NULL)
  63                 snprintf(buf, size, "python.%s.%s", module, name);
  64         else
  65                 snprintf(buf, size, "python.%s.%p", module, callback);
  66         Py_XDECREF(mod);
  67         Py_XDECREF(n);
  68 }
  69
  70 static int cpy_read_callback(user_data_t *data) {
  71         cpy_callback_t *c = data->data;
  72         PyObject *ret;
  73
  74         CPY_LOCK_THREADS
  75                 ret = PyObject_CallFunctionObjArgs(c->callback, c->data, (void *) 0); /* New reference. */
  76                 if (ret == NULL) {
  77                         /* FIXME */
  78                         PyErr_Print();
  79                 } else {
  80                         Py_DECREF(ret);
  81                 }
  82         CPY_RELEASE_THREADS
  83         return 0;
  84 }
  85
  86 static int cpy_write_callback(const data_set_t *ds, const value_list_t *value_list, user_data_t *data) {
  87         int i;
  88         cpy_callback_t *c = data->data;
  89         PyObject *ret, *v, *list;
  90
  91         CPY_LOCK_THREADS
  92                 list = PyList_New(value_list->values_len); /* New reference. */
  93                 if (list == NULL) {
  94                         PyErr_Print();
  95                         CPY_RETURN_FROM_THREADS 0;
  96                 }
  97                 for (i = 0; i < value_list->values_len; ++i) {
  98                         if (ds->ds->type == DS_TYPE_COUNTER) {
  99                                 if ((long) value_list->values[i].counter == value_list->values[i].counter)
 100                                         PyList_SetItem(list, i, PyInt_FromLong(value_list->values[i].counter));
 101                                 else
 102                                         PyList_SetItem(list, i, PyLong_FromUnsignedLongLong(value_list->values[i].counter));
 103                         } else if (ds->ds->type == DS_TYPE_GAUGE) {
 104                                 PyList_SetItem(list, i, PyFloat_FromDouble(value_list->values[i].gauge));
 105                         } else if (ds->ds->type == DS_TYPE_DERIVE) {
 106                                 if ((long) value_list->values[i].derive == value_list->values[i].derive)
 107                                         PyList_SetItem(list, i, PyInt_FromLong(value_list->values[i].derive));
 108                                 else
 109                                         PyList_SetItem(list, i, PyLong_FromLongLong(value_list->values[i].derive));
 110                         } else if (ds->ds->type == DS_TYPE_ABSOLUTE) {
 111                                 if ((long) value_list->values[i].absolute == value_list->values[i].absolute)
 112                                         PyList_SetItem(list, i, PyInt_FromLong(value_list->values[i].absolute));
 113                                 else
 114                                         PyList_SetItem(list, i, PyLong_FromUnsignedLongLong(value_list->values[i].absolute));
 115                         } else {
 116                                 ERROR("cpy_write_callback: Unknown value type %d.", ds->ds->type);
 117                                 Py_DECREF(list);
 118                                 CPY_RETURN_FROM_THREADS 0;
 119                         }
 120                         if (PyErr_Occurred() != NULL) {
 121                                 PyErr_Print();
 122                                 CPY_RETURN_FROM_THREADS 0;
 123                         }
 124                 }
 125                 v = PyObject_CallFunction((PyObject *) &ValuesType, "sOssssdi", value_list->type, list,
 126                                 value_list->plugin_instance, value_list->type_instance, value_list->plugin,
 127                                 value_list->host, (double) value_list->time, value_list->interval);
 128                 Py_DECREF(list);
 129                 ret = PyObject_CallFunctionObjArgs(c->callback, v, c->data, (void *) 0); /* New reference. */
 130                 if (ret == NULL) {
 131                         /* FIXME */
 132                         PyErr_Print();
 133                 } else {
 134                         Py_DECREF(ret);
 135                 }
 136         CPY_RELEASE_THREADS
 137         return 0;
 138 }
 139
 140 static void cpy_log_callback(int severity, const char *message, user_data_t *data) {
 141         cpy_callback_t * c = data->data;
 142         PyObject *ret;
 143
 144         CPY_LOCK_THREADS
 145         if (c->data == NULL)
 146                 ret = PyObject_CallFunction(c->callback, "is", severity, message); /* New reference. */
 147         else
 148                 ret = PyObject_CallFunction(c->callback, "isO", severity, message, c->data); /* New reference. */
 149
 150         if (ret == NULL) {
 151                 /* FIXME */
 152                 PyErr_Print();
 153         } else {
 154                 Py_DECREF(ret);
 155         }
 156         CPY_RELEASE_THREADS
 157 }
 158
 159 static PyObject *cpy_register_generic(cpy_callback_t **list_head, PyObject *args, PyObject *kwds) {
 160         cpy_callback_t *c;
 161         const char *name = NULL;
 162         PyObject *callback = NULL, *data = NULL, *mod = NULL;
 163         static char *kwlist[] = {"callback", "data", "name", NULL};
 164
 165         if (PyArg_ParseTupleAndKeywords(args, kwds, "O|Oz", kwlist, &callback, &data, &name) == 0) return NULL;
 166         if (PyCallable_Check(callback) == 0) {
 167                 PyErr_SetString(PyExc_TypeError, "callback needs a be a callable object.");
 168                 return NULL;
 169         }
 170         if (name == NULL) {
 171                 mod = PyObject_GetAttrString(callback, "__module__"); /* New reference. */
 172                 if (mod != NULL) name = PyString_AsString(mod);
 173                 if (name == NULL) {
 174                         Py_XDECREF(mod);
 175                         PyErr_SetString(PyExc_ValueError, "No module name specified and "
 176                                 "callback function does not have a \"__module__\" attribute.");
 177                         return NULL;
 178                 }
 179         }
 180         Py_INCREF(callback);
 181         Py_XINCREF(data);
 182         c = malloc(sizeof(*c));
 183         c->name = strdup(name);
 184         c->callback = callback;
 185         c->data = data;
 186         c->next = *list_head;
 187         *list_head = c;
 188         Py_XDECREF(mod);
 189         Py_RETURN_NONE;
 190 }
 191
 192 static PyObject *cpy_register_config(PyObject *self, PyObject *args, PyObject *kwds) {
 193         return cpy_register_generic(&cpy_config_callbacks, args, kwds);
 194 }
 195
 196 static PyObject *cpy_register_init(PyObject *self, PyObject *args, PyObject *kwds) {
 197         return cpy_register_generic(&cpy_init_callbacks, args, kwds);
 198 }
 199
 200 typedef int reg_function_t(const char *name, void *callback, void *data);
 201
 202 static PyObject *cpy_register_generic_userdata(void *reg, void *handler, PyObject *args, PyObject *kwds) {
 203         char buf[512];
 204         reg_function_t *register_function = (reg_function_t *) reg;
 205         cpy_callback_t *c = NULL;
 206         user_data_t *user_data = NULL;
 207         const char *name = NULL;
 208         PyObject *callback = NULL, *data = NULL;
 209         static char *kwlist[] = {"callback", "data", "name", NULL};
 210
 211         if (PyArg_ParseTupleAndKeywords(args, kwds, "O|Oz", kwlist, &callback, &data, &name) == 0) return NULL;
 212         if (PyCallable_Check(callback) == 0) {
 213                 PyErr_SetString(PyExc_TypeError, "callback needs a be a callable object.");
 214                 return NULL;
 215         }
 216         cpy_build_name(buf, sizeof(buf), callback, name);
 217
 218         Py_INCREF(callback);
 219         Py_XINCREF(data);
 220         c = malloc(sizeof(*c));
 221         c->name = strdup(buf);
 222         c->callback = callback;
 223         c->data = data;
 224         c->next = NULL;
 225         user_data = malloc(sizeof(*user_data));
 226         user_data->free_func = cpy_destroy_user_data;
 227         user_data->data = c;
 228         register_function(buf, handler, user_data);
 229         return PyString_FromString(buf);
 230 }
 231
 232 static PyObject *cpy_register_read(PyObject *self, PyObject *args, PyObject *kwds) {
 233         char buf[512];
 234         cpy_callback_t *c = NULL;
 235         user_data_t *user_data = NULL;
 236         double interval = 0;
 237         const char *name = NULL;
 238         PyObject *callback = NULL, *data = NULL;
 239         struct timespec ts;
 240         static char *kwlist[] = {"callback", "interval", "data", "name", NULL};
 241
 242         if (PyArg_ParseTupleAndKeywords(args, kwds, "O|dOz", kwlist, &callback, &interval, &data, &name) == 0) return NULL;
 243         if (PyCallable_Check(callback) == 0) {
 244                 PyErr_SetString(PyExc_TypeError, "callback needs a be a callable object.");
 245                 return NULL;
 246         }
 247         cpy_build_name(buf, sizeof(buf), callback, name);
 248
 249         Py_INCREF(callback);
 250         Py_XINCREF(data);
 251         c = malloc(sizeof(*c));
 252         c->name = strdup(buf);
 253         c->callback = callback;
 254         c->data = data;
 255         c->next = NULL;
 256         user_data = malloc(sizeof(*user_data));
 257         user_data->free_func = cpy_destroy_user_data;
 258         user_data->data = c;
 259         ts.tv_sec = interval;
 260         ts.tv_nsec = (interval - ts.tv_sec) * 1000000000;
 261         plugin_register_complex_read(buf, cpy_read_callback, &ts, user_data);
 262         return PyString_FromString(buf);
 263 }
 264
 265 static PyObject *cpy_register_log(PyObject *self, PyObject *args, PyObject *kwds) {
 266         return cpy_register_generic_userdata(plugin_register_log, cpy_log_callback, args, kwds);
 267 }
 268
 269 static PyObject *cpy_register_write(PyObject *self, PyObject *args, PyObject *kwds) {
 270         return cpy_register_generic_userdata(plugin_register_write, cpy_write_callback, args, kwds);
 271 }
 272
 273 static PyObject *cpy_register_shutdown(PyObject *self, PyObject *args, PyObject *kwds) {
 274         return cpy_register_generic(&cpy_shutdown_callbacks, args, kwds);
 275 }
 276
 277 static PyObject *cpy_Error(PyObject *self, PyObject *args) {
 278         const char *text;
 279         if (PyArg_ParseTuple(args, "s", &text) == 0) return NULL;
 280         Py_BEGIN_ALLOW_THREADS
 281         plugin_log(LOG_ERR, "%s", text);
 282         Py_END_ALLOW_THREADS
 283         Py_RETURN_NONE;
 284 }
 285
 286 static PyObject *cpy_Warning(PyObject *self, PyObject *args) {
 287         const char *text;
 288         if (PyArg_ParseTuple(args, "s", &text) == 0) return NULL;
 289         Py_BEGIN_ALLOW_THREADS
 290         plugin_log(LOG_WARNING, "%s", text);
 291         Py_END_ALLOW_THREADS
 292         Py_RETURN_NONE;
 293 }
 294
 295 static PyObject *cpy_Notice(PyObject *self, PyObject *args) {
 296         const char *text;
 297         if (PyArg_ParseTuple(args, "s", &text) == 0) return NULL;
 298         Py_BEGIN_ALLOW_THREADS
 299         plugin_log(LOG_NOTICE, "%s", text);
 300         Py_END_ALLOW_THREADS
 301         Py_RETURN_NONE;
 302 }
 303
 304 static PyObject *cpy_Info(PyObject *self, PyObject *args) {
 305         const char *text;
 306         if (PyArg_ParseTuple(args, "s", &text) == 0) return NULL;
 307         Py_BEGIN_ALLOW_THREADS
 308         plugin_log(LOG_INFO, "%s", text);
 309         Py_END_ALLOW_THREADS
 310         Py_RETURN_NONE;
 311 }
 312
 313 static PyObject *cpy_Debug(PyObject *self, PyObject *args) {
 314 #ifdef COLLECT_DEBUG
 315         const char *text;
 316         if (PyArg_ParseTuple(args, "s", &text) == 0) return NULL;
 317         plugin_log(LOG_DEBUG, "%s", text);
 318 #endif
 319         Py_RETURN_NONE;
 320 }
 321
 322 static PyMethodDef cpy_methods[] = {
 323         {"Debug", cpy_Debug, METH_VARARGS, "This is an unhelpful text."},
 324         {"Info", cpy_Info, METH_VARARGS, "This is an unhelpful text."},
 325         {"Notice", cpy_Notice, METH_VARARGS, "This is an unhelpful text."},
 326         {"Warning", cpy_Warning, METH_VARARGS, "This is an unhelpful text."},
 327         {"Error", cpy_Error, METH_VARARGS, "This is an unhelpful text."},
 328         {"register_log", (PyCFunction) cpy_register_log, METH_VARARGS | METH_KEYWORDS, "This is an unhelpful text."},
 329         {"register_init", (PyCFunction) cpy_register_init, METH_VARARGS | METH_KEYWORDS, "This is an unhelpful text."},
 330         {"register_config", (PyCFunction) cpy_register_config, METH_VARARGS | METH_KEYWORDS, "This is an unhelpful text."},
 331         {"register_read", (PyCFunction) cpy_register_read, METH_VARARGS | METH_KEYWORDS, "This is an unhelpful text."},
 332         {"register_write", (PyCFunction) cpy_register_write, METH_VARARGS | METH_KEYWORDS, "This is an unhelpful text."},
 333         {"register_shutdown", (PyCFunction) cpy_register_shutdown, METH_VARARGS | METH_KEYWORDS, "This is an unhelpful text."},
 334         {0, 0, 0, 0}
 335 };
 336
 337 static int cpy_shutdown(void) {
 338         cpy_callback_t *c;
 339         PyObject *ret;
 340
 341         /* This can happen if the module was loaded but not configured. */
 342         if (state != NULL)
 343                 PyEval_RestoreThread(state);
 344
 345         for (c = cpy_shutdown_callbacks; c; c = c->next) {
 346                 ret = PyObject_CallFunctionObjArgs(c->callback, c->data, (void *) 0); /* New reference. */
 347                 if (ret == NULL)
 348                         PyErr_Print(); /* FIXME */
 349                 else
 350                         Py_DECREF(ret);
 351         }
 352         Py_Finalize();
 353         return 0;
 354 }
 355
 356 static int cpy_init(void) {
 357         cpy_callback_t *c;
 358         PyObject *ret;
 359
 360         PyEval_InitThreads();
 361         /* Now it's finally OK to use python threads. */
 362         for (c = cpy_init_callbacks; c; c = c->next) {
 363                 ret = PyObject_CallFunctionObjArgs(c->callback, c->data, (void *) 0); /* New reference. */
 364                 if (ret == NULL)
 365                         PyErr_Print(); /* FIXME */
 366                 else
 367                         Py_DECREF(ret);
 368         }
 369         state = PyEval_SaveThread();
 370         return 0;
 371 }
 372
 373 static PyObject *cpy_oconfig_to_pyconfig(oconfig_item_t *ci, PyObject *parent) {
 374         int i;
 375         PyObject *item, *values, *children, *tmp;
 376
 377         if (parent == NULL)
 378                 parent = Py_None;
 379
 380         values = PyTuple_New(ci->values_num); /* New reference. */
 381         for (i = 0; i < ci->values_num; ++i) {
 382                 if (ci->values[i].type == OCONFIG_TYPE_STRING) {
 383                         PyTuple_SET_ITEM(values, i, PyString_FromString(ci->values[i].value.string));
 384                 } else if (ci->values[i].type == OCONFIG_TYPE_NUMBER) {
 385                         PyTuple_SET_ITEM(values, i, PyFloat_FromDouble(ci->values[i].value.number));
 386                 } else if (ci->values[i].type == OCONFIG_TYPE_BOOLEAN) {
 387                         PyTuple_SET_ITEM(values, i, PyBool_FromLong(ci->values[i].value.boolean));
 388                 }
 389         }
 390
 391         item = PyObject_CallFunction((PyObject *) &ConfigType, "sONO", ci->key, parent, values, Py_None);
 392         if (item == NULL)
 393                 return NULL;
 394         children = PyTuple_New(ci->children_num); /* New reference. */
 395         for (i = 0; i < ci->children_num; ++i) {
 396                         PyTuple_SET_ITEM(children, i, cpy_oconfig_to_pyconfig(ci->children + i, item));
 397         }
 398         tmp = ((Config *) item)->children;
 399         ((Config *) item)->children = children;
 400         Py_XDECREF(tmp);
 401         return item;
 402 }
 403
 404 static int cpy_config(oconfig_item_t *ci) {
 405         int i;
 406         PyObject *sys;
 407         PyObject *sys_path;
 408         PyObject *module;
 409
 410         /* Ok in theory we shouldn't do initialization at this point
 411          * but we have to. In order to give python scripts a chance
 412          * to register a config callback we need to be able to execute
 413          * python code during the config callback so we have to start
 414          * the interpreter here. */
 415         /* Do *not* use the python "thread" module at this point! */
 416         Py_Initialize();
 417
 418         PyType_Ready(&ConfigType);
 419         PyType_Ready(&ValuesType);
 420         sys = PyImport_ImportModule("sys"); /* New reference. */
 421         if (sys == NULL) {
 422                 ERROR("python module: Unable to import \"sys\" module.");
 423                 /* Just print the default python exception text to stderr. */
 424                 PyErr_Print();
 425                 return 1;
 426         }
 427         sys_path = PyObject_GetAttrString(sys, "path"); /* New reference. */
 428         Py_DECREF(sys);
 429         if (sys_path == NULL) {
 430                 ERROR("python module: Unable to read \"sys.path\".");
 431                 PyErr_Print();
 432                 return 1;
 433         }
 434         module = Py_InitModule("collectd", cpy_methods); /* Borrowed reference. */
 435         PyModule_AddObject(module, "Config", (PyObject *) &ConfigType); /* Steals a reference. */
 436         PyModule_AddObject(module, "Values", (PyObject *) &ValuesType); /* Steals a reference. */
 437         PyModule_AddIntConstant(module, "LOG_DEBUG", LOG_DEBUG);
 438         PyModule_AddIntConstant(module, "LOG_INFO", LOG_INFO);
 439         PyModule_AddIntConstant(module, "LOG_NOTICE", LOG_NOTICE);
 440         PyModule_AddIntConstant(module, "LOG_WARNING", LOG_WARNING);
 441         PyModule_AddIntConstant(module, "LOG_ERROR", LOG_ERR);
 442         for (i = 0; i < ci->children_num; ++i) {
 443                 oconfig_item_t *item = ci->children + i;
 444
 445                 if (strcasecmp(item->key, "ModulePath") == 0) {
 446                         char *dir = NULL;
 447                         PyObject *dir_object;
 448
 449                         if (cf_util_get_string(item, &dir) != 0)
 450                                 continue;
 451                         dir_object = PyString_FromString(dir); /* New reference. */
 452                         if (dir_object == NULL) {
 453                                 ERROR("python plugin: Unable to convert \"%s\" to "
 454                                       "a python object.", dir);
 455                                 free(dir);
 456                                 PyErr_Print();
 457                                 continue;
 458                         }
 459                         if (PyList_Append(sys_path, dir_object) != 0) {
 460                                 ERROR("python plugin: Unable to append \"%s\" to "
 461                                       "python module path.", dir);
 462                                 PyErr_Print();
 463                         }
 464                         Py_DECREF(dir_object);
 465                         free(dir);
 466                 } else if (strcasecmp(item->key, "Import") == 0) {
 467                         char *module_name = NULL;
 468                         PyObject *module;
 469
 470                         if (cf_util_get_string(item, &module_name) != 0)
 471                                 continue;
 472                         module = PyImport_ImportModule(module_name); /* New reference. */
 473                         if (module == NULL) {
 474                                 ERROR("python plugin: Error importing module \"%s\".", module_name);
 475                                 PyErr_Print();
 476                         }
 477                         free(module_name);
 478                         Py_XDECREF(module);
 479                 } else if (strcasecmp(item->key, "Module") == 0) {
 480                         char *name = NULL;
 481                         cpy_callback_t *c;
 482                         PyObject *ret;
 483
 484                         if (cf_util_get_string(item, &name) != 0)
 485                                 continue;
 486                         for (c = cpy_config_callbacks; c; c = c->next) {
 487                                 if (strcasecmp(c->name, name) == 0)
 488                                         break;
 489                         }
 490                         if (c == NULL) {
 491                                 WARNING("python plugin: Found a configuration for the \"%s\" plugin, "
 492                                         "but the plugin isn't loaded or didn't register "
 493                                         "a configuration callback.", name);
 494                                 free(name);
 495                                 continue;
 496                         }
 497                         free(name);
 498                         if (c->data == NULL)
 499                                 ret = PyObject_CallFunction(c->callback, "N",
 500                                         cpy_oconfig_to_pyconfig(item, NULL)); /* New reference. */
 501                         else
 502                                 ret = PyObject_CallFunction(c->callback, "NO",
 503                                         cpy_oconfig_to_pyconfig(item, NULL), c->data); /* New reference. */
 504                         if (ret == NULL)
 505                                 PyErr_Print();
 506                         else
 507                                 Py_DECREF(ret);
 508                 } else {
 509                         WARNING("python plugin: Ignoring unknown config key \"%s\".", item->key);
 510                 }
 511         }
 512         Py_DECREF(sys_path);
 513         return 0;
 514 }
 515
 516 void module_register(void) {
 517         plugin_register_complex_config("python", cpy_config);
 518         plugin_register_init("python", cpy_init);
 519 //      plugin_register_read("python", cna_read);
 520         plugin_register_shutdown("python", cpy_shutdown);
 521 }