| # vim: expandtab ts=4 sw=4: |
| # ================================================================================== |
| # Copyright (c) 2019-2020 Nokia |
| # Copyright (c) 2018-2020 AT&T Intellectual Property. |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| # ================================================================================== |
| import uuid |
| import json |
| from ctypes import RTLD_GLOBAL, Structure, c_int, POINTER, c_char, c_char_p, c_void_p, memmove, cast |
| from ctypes import CDLL |
| from ctypes import create_string_buffer |
| from ricxappframe.rmr.exceptions import BadBufferAllocation, MeidSizeOutOfRange, InitFailed |
| |
| # https://docs.python.org/3.7/library/ctypes.html |
| # https://stackoverflow.com/questions/2327344/ctypes-loading-a-c-shared-library-that-has-dependencies/30845750#30845750 |
| # make sure you do a set -x LD_LIBRARY_PATH /usr/local/lib/; |
| |
| # even though we don't use these directly, they contain symbols we need |
| rmr_c_lib = CDLL("librmr_si.so", mode=RTLD_GLOBAL) |
| |
| |
| # Internal Helpers (not a part of public api) |
| |
| |
| _rmr_const = rmr_c_lib.rmr_get_consts |
| _rmr_const.argtypes = [] |
| _rmr_const.restype = c_char_p |
| |
| |
| def _get_constants(cache={}): |
| """ |
| Get or build needed constants from rmr |
| TODO: are there constants that end user applications need? |
| """ |
| if cache: |
| return cache |
| |
| js = _rmr_const() # read json string |
| cache = json.loads(str(js.decode())) # create constants value object as a hash |
| return cache |
| |
| |
| def _get_mapping_dict(cache={}): |
| """ |
| Get or build the state mapping dict |
| |
| RMR_OK 0 state is good |
| RMR_ERR_BADARG 1 argument passd to function was unusable |
| RMR_ERR_NOENDPT 2 send/call could not find an endpoint based on msg type |
| RMR_ERR_EMPTY 3 msg received had no payload; attempt to send an empty message |
| RMR_ERR_NOHDR 4 message didn't contain a valid header |
| RMR_ERR_SENDFAILED 5 send failed; errno has nano reason |
| RMR_ERR_CALLFAILED 6 unable to send call() message |
| RMR_ERR_NOWHOPEN 7 no wormholes are open |
| RMR_ERR_WHID 8 wormhole id was invalid |
| RMR_ERR_OVERFLOW 9 operation would have busted through a buffer/field size |
| RMR_ERR_RETRY 10 request (send/call/rts) failed, but caller should retry (EAGAIN for wrappers) |
| RMR_ERR_RCVFAILED 11 receive failed (hard error) |
| RMR_ERR_TIMEOUT 12 message processing call timed out |
| RMR_ERR_UNSET 13 the message hasn't been populated with a transport buffer |
| RMR_ERR_TRUNC 14 received message likely truncated |
| RMR_ERR_INITFAILED 15 initialization of something (probably message) failed |
| |
| """ |
| if cache: |
| return cache |
| |
| rmr_consts = _get_constants() |
| for key in rmr_consts: # build the state mapping dict |
| if key[:7] in ["RMR_ERR", "RMR_OK"]: |
| en = int(rmr_consts[key]) |
| cache[en] = key |
| |
| return cache |
| |
| |
| def _state_to_status(stateno): |
| """ |
| Convert a msg state to status |
| |
| """ |
| sdict = _get_mapping_dict() |
| return sdict.get(stateno, "UNKNOWN STATE") |
| |
| |
| _RCONST = _get_constants() |
| |
| |
| ############## |
| # PUBLIC API |
| ############## |
| |
| |
| # These constants are directly usable by importers of this library |
| # TODO: Are there others that will be useful? |
| |
| RMR_MAX_RCV_BYTES = _RCONST["RMR_MAX_RCV_BYTES"] |
| RMRFL_MTCALL = _RCONST.get("RMRFL_MTCALL", 0x02) # initialization flags |
| RMRFL_NONE = _RCONST.get("RMRFL_NONE", 0x0) |
| RMR_OK = _RCONST["RMR_OK"] # useful state constants |
| RMR_ERR_TIMEOUT = _RCONST["RMR_ERR_TIMEOUT"] |
| RMR_ERR_RETRY = _RCONST["RMR_ERR_RETRY"] |
| |
| |
| class rmr_mbuf_t(Structure): |
| """ |
| Reimplementation of rmr_mbuf_t which is in an unaccessible header file (src/common/include/rmr.h) |
| |
| | typedef struct { |
| | int state; // state of processing |
| | int mtype; // message type |
| | int len; // length of data in the payload (send or received) |
| | unsigned char* payload; // transported data |
| | unsigned char* xaction; // pointer to fixed length transaction id bytes |
| | int sub_id; // subscription id |
| | int tp_state; // transport state (a.k.a errno) |
| | |
| | these things are off limits to the user application |
| | |
| | void* tp_buf; // underlying transport allocated pointer (e.g. nng message) |
| | void* header; // internal message header (whole buffer: header+payload) |
| | unsigned char* id; // if we need an ID in the message separate from the xaction id |
| | int flags; // various MFL (private) flags as needed |
| | int alloc_len; // the length of the allocated space (hdr+payload) |
| | } rmr_mbuf_t; |
| |
| We do not include the fields we are not supposed to mess with |
| |
| RE PAYLOADs type below, see the documentation for c_char_p: |
| class ctypes.c_char_p |
| Represents the C char * datatype when it points to a zero-terminated string. For a general character pointer that may also point to binary data, POINTER(c_char) must be used. The constructor accepts an integer address, or a bytes object. |
| """ |
| |
| _fields_ = [ |
| ("state", c_int), |
| ("mtype", c_int), |
| ("len", c_int), |
| ( |
| "payload", |
| POINTER(c_char), |
| ), # according to th following the python bytes are already unsinged https://bytes.com/topic/python/answers/695078-ctypes-unsigned-char |
| ("xaction", POINTER(c_char)), |
| ("sub_id", c_int), |
| ("tp_state", c_int), |
| ] |
| |
| |
| # argtypes and restype are important: https://stackoverflow.com/questions/24377845/ctype-why-specify-argtypes |
| |
| |
| _rmr_init = rmr_c_lib.rmr_init |
| _rmr_init.argtypes = [c_char_p, c_int, c_int] |
| _rmr_init.restype = c_void_p |
| |
| |
| def rmr_init(uproto_port, max_msg_size, flags): |
| """ |
| Refer to rmr C documentation for rmr_init |
| extern void* rmr_init(char* uproto_port, int max_msg_size, int flags) |
| |
| This python function checks that the context is not None and raises |
| an excption if it is. |
| """ |
| mrc = _rmr_init(uproto_port, max_msg_size, flags) |
| if mrc is None: |
| raise InitFailed() |
| return mrc |
| |
| |
| _rmr_ready = rmr_c_lib.rmr_ready |
| _rmr_ready.argtypes = [c_void_p] |
| _rmr_ready.restype = c_int |
| |
| |
| def rmr_ready(vctx): |
| """ |
| Refer to rmr C documentation for rmr_ready |
| extern int rmr_ready(void* vctx) |
| """ |
| return _rmr_ready(vctx) |
| |
| |
| _rmr_close = rmr_c_lib.rmr_close |
| _rmr_close.argtypes = [c_void_p] |
| |
| |
| def rmr_close(vctx): |
| """ |
| Refer to rmr C documentation for rmr_close |
| extern void rmr_close(void* vctx) |
| """ |
| return _rmr_close(vctx) |
| |
| |
| _rmr_set_stimeout = rmr_c_lib.rmr_set_stimeout |
| _rmr_set_stimeout.argtypes = [c_void_p, c_int] |
| _rmr_set_stimeout.restype = c_int |
| |
| |
| def rmr_set_stimeout(vctx, time): |
| """ |
| Refer to the rmr C documentation for rmr_set_stimeout |
| extern int rmr_set_stimeout(void* vctx, int time) |
| """ |
| return _rmr_set_stimeout(vctx, time) |
| |
| |
| _rmr_alloc_msg = rmr_c_lib.rmr_alloc_msg |
| _rmr_alloc_msg.argtypes = [c_void_p, c_int] |
| _rmr_alloc_msg.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_alloc_msg( |
| vctx, size, payload=None, gen_transaction_id=False, mtype=None, meid=None, sub_id=None, fixed_transaction_id=None |
| ): |
| """ |
| Refer to the rmr C documentation for rmr_alloc_msg |
| extern rmr_mbuf_t* rmr_alloc_msg(void* vctx, int size) |
| TODO: on next API break, clean up transaction_id ugliness. Kept for now to preserve API. |
| |
| if payload is not None, attempts to set the payload |
| if gen_transaction_id is True, it generates and sets a transaction id. Note, fixed_transaction_id supersedes this option |
| if mtype is not None, sets the sbuf's message type |
| if meid is not None, sets the sbuf's meid |
| if sub_id is not None, sets the sbud's subscription id |
| if fixed_transaction_id is set, it deterministically sets the transaction_id. This overrides the option gen_transation_id |
| |
| """ |
| sbuf = _rmr_alloc_msg(vctx, size) |
| try: |
| # make sure the alloc worked |
| sbuf.contents |
| |
| # set specified fields |
| if payload: |
| set_payload_and_length(payload, sbuf) |
| |
| if fixed_transaction_id: |
| set_transaction_id(sbuf, fixed_transaction_id) |
| elif gen_transaction_id: |
| generate_and_set_transaction_id(sbuf) |
| |
| if mtype: |
| sbuf.contents.mtype = mtype |
| |
| if meid: |
| rmr_set_meid(sbuf, meid) |
| |
| if sub_id: |
| sbuf.contents.sub_id = sub_id |
| |
| return sbuf |
| |
| except ValueError: |
| raise BadBufferAllocation |
| |
| |
| _rmr_realloc_payload = rmr_c_lib.rmr_realloc_payload |
| _rmr_realloc_payload.argtypes = [POINTER(rmr_mbuf_t), c_int, c_int, c_int] # new_len, copy, clone |
| _rmr_realloc_payload.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_realloc_payload(ptr_mbuf, new_len, copy=False, clone=False): |
| """ |
| Refer to the rmr C documentation for rmr_realloc_payload(). |
| extern rmr_mbuf_t* rmr_realloc_payload(rmr_mbuf_t*, int, int, int) |
| """ |
| return _rmr_realloc_payload(ptr_mbuf, new_len, copy, clone) |
| |
| |
| _rmr_free_msg = rmr_c_lib.rmr_free_msg |
| _rmr_free_msg.argtypes = [c_void_p] |
| _rmr_free_msg.restype = None |
| |
| |
| def rmr_free_msg(mbuf): |
| """ |
| Refer to the rmr C documentation for rmr_free_msg |
| extern void rmr_free_msg(rmr_mbuf_t* mbuf ) |
| """ |
| if mbuf is not None: |
| _rmr_free_msg(mbuf) |
| |
| |
| _rmr_payload_size = rmr_c_lib.rmr_payload_size |
| _rmr_payload_size.argtypes = [POINTER(rmr_mbuf_t)] |
| _rmr_payload_size.restype = c_int |
| |
| |
| def rmr_payload_size(ptr_mbuf): |
| """ |
| Refer to the rmr C documentation for rmr_payload_size |
| extern int rmr_payload_size(rmr_mbuf_t* msg) |
| """ |
| return _rmr_payload_size(ptr_mbuf) |
| |
| |
| """ |
| The following functions all seem to have the same interface |
| """ |
| |
| _rmr_send_msg = rmr_c_lib.rmr_send_msg |
| _rmr_send_msg.argtypes = [c_void_p, POINTER(rmr_mbuf_t)] |
| _rmr_send_msg.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_send_msg(vctx, ptr_mbuf): |
| """ |
| Refer to the rmr C documentation for rmr_send_msg |
| extern rmr_mbuf_t* rmr_send_msg(void* vctx, rmr_mbuf_t* msg) |
| """ |
| return _rmr_send_msg(vctx, ptr_mbuf) |
| |
| |
| # TODO: the old message (Send param) is actually optional, but I don't know how to specify that in Ctypes. |
| _rmr_rcv_msg = rmr_c_lib.rmr_rcv_msg |
| _rmr_rcv_msg.argtypes = [c_void_p, POINTER(rmr_mbuf_t)] |
| _rmr_rcv_msg.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_rcv_msg(vctx, ptr_mbuf): |
| """ |
| Refer to the rmr C documentation for rmr_rcv_msg |
| extern rmr_mbuf_t* rmr_rcv_msg(void* vctx, rmr_mbuf_t* old_msg) |
| """ |
| return _rmr_rcv_msg(vctx, ptr_mbuf) |
| |
| |
| _rmr_torcv_msg = rmr_c_lib.rmr_torcv_msg |
| _rmr_torcv_msg.argtypes = [c_void_p, POINTER(rmr_mbuf_t), c_int] |
| _rmr_torcv_msg.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_torcv_msg(vctx, ptr_mbuf, ms_to): |
| """ |
| Refer to the rmr C documentation for rmr_torcv_msg |
| extern rmr_mbuf_t* rmr_torcv_msg(void* vctx, rmr_mbuf_t* old_msg, int ms_to) |
| """ |
| return _rmr_torcv_msg(vctx, ptr_mbuf, ms_to) |
| |
| |
| _rmr_rts_msg = rmr_c_lib.rmr_rts_msg |
| _rmr_rts_msg.argtypes = [c_void_p, POINTER(rmr_mbuf_t)] |
| _rmr_rts_msg.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_rts_msg(vctx, ptr_mbuf, payload=None, mtype=None): |
| """ |
| Refer to the rmr C documentation for rmr_rts_msg |
| extern rmr_mbuf_t* rmr_rts_msg(void* vctx, rmr_mbuf_t* msg) |
| |
| additional features beyond c-rmr: |
| if payload is not None, attempts to set the payload |
| if mtype is not None, sets the sbuf's message type |
| """ |
| |
| if payload: |
| set_payload_and_length(payload, ptr_mbuf) |
| |
| if mtype: |
| ptr_mbuf.contents.mtype = mtype |
| |
| return _rmr_rts_msg(vctx, ptr_mbuf) |
| |
| |
| _rmr_call = rmr_c_lib.rmr_call |
| _rmr_call.argtypes = [c_void_p, POINTER(rmr_mbuf_t)] |
| _rmr_call.restype = POINTER(rmr_mbuf_t) |
| |
| |
| def rmr_call(vctx, ptr_mbuf): |
| """ |
| Refer to the rmr C documentation for rmr_call |
| extern rmr_mbuf_t* rmr_call(void* vctx, rmr_mbuf_t* msg) |
| """ |
| return _rmr_call(vctx, ptr_mbuf) |
| |
| |
| _rmr_bytes2meid = rmr_c_lib.rmr_bytes2meid |
| _rmr_bytes2meid.argtypes = [POINTER(rmr_mbuf_t), c_char_p, c_int] |
| _rmr_bytes2meid.restype = c_int |
| |
| |
| def rmr_set_meid(ptr_mbuf, byte_str): |
| """ |
| Refer to the rmr C documentation for rmr_bytes2meid |
| extern int rmr_bytes2meid(rmr_mbuf_t* mbuf, unsigned char const* src, int len); |
| |
| Caution: the meid length supported in an RMR message is 32 bytes, but C applications |
| expect this to be a nil terminated string and thus only 31 bytes are actually available. |
| |
| Raises: exceptions.MeidSizeOutOfRang |
| """ |
| max = _get_constants().get("RMR_MAX_MEID", 32) |
| if len(byte_str) >= max: |
| raise MeidSizeOutOfRange |
| |
| return _rmr_bytes2meid(ptr_mbuf, byte_str, len(byte_str)) |
| |
| |
| # CAUTION: Some of the C functions expect a mutable buffer to copy the bytes into; |
| # if there is a get_* function below, use it to set up and return the |
| # buffer properly. |
| |
| # extern unsigned char* rmr_get_meid(rmr_mbuf_t* mbuf, unsigned char* dest); |
| # we don't provide direct access to this function (unless it is asked for) because it is not really useful to provide your own buffer. |
| # Rather, rmr_get_meid does this for you, and just returns the string. |
| _rmr_get_meid = rmr_c_lib.rmr_get_meid |
| _rmr_get_meid.argtypes = [POINTER(rmr_mbuf_t), c_char_p] |
| _rmr_get_meid.restype = c_char_p |
| |
| |
| def rmr_get_meid(ptr_mbuf): |
| """ |
| Get the managed equipment ID (meid) from the message header. |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| |
| Returns |
| ------- |
| string: |
| meid |
| """ |
| sz = _get_constants().get("RMR_MAX_MEID", 32) # size for buffer to fill |
| buf = create_string_buffer(sz) |
| _rmr_get_meid(ptr_mbuf, buf) |
| return buf.value |
| |
| |
| _rmr_get_src = rmr_c_lib.rmr_get_src |
| _rmr_get_src.argtypes = [POINTER(rmr_mbuf_t), c_char_p] |
| _rmr_get_src.restype = c_char_p |
| |
| |
| def rmr_get_src(ptr_mbuf, dest): |
| """ |
| Refer to the rmr C documentation for rmr_get_src |
| extern unsigned char* rmr_get_src(rmr_mbuf_t* mbuf, unsigned char* dest); |
| """ |
| return _rmr_get_src(ptr_mbuf, dest) |
| |
| |
| # Methods that exist ONLY in rmr-python, and are not wrapped methods |
| # In hindsight, I wish i put these in a seperate module, but leaving this here to prevent api breakage. |
| |
| |
| def get_payload(ptr_mbuf): |
| """ |
| Given a rmr_buf_t*, get it's binary payload as a bytes object |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| |
| Returns |
| ------- |
| bytes: |
| the message payload |
| """ |
| # Logic came from the answer here: https://stackoverflow.com/questions/55103298/python-ctypes-read-pointerc-char-in-python |
| sz = ptr_mbuf.contents.len |
| CharArr = c_char * sz |
| return CharArr(*ptr_mbuf.contents.payload[:sz]).raw |
| |
| |
| def get_xaction(ptr_mbuf): |
| """ |
| given a rmr_buf_t*, get it's transaction id |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| |
| Returns |
| ------- |
| bytes: |
| the transaction id |
| """ |
| val = cast(ptr_mbuf.contents.xaction, c_char_p).value |
| sz = _get_constants().get("RMR_MAX_XID", 0) |
| return val[:sz] |
| |
| |
| def message_summary(ptr_mbuf): |
| """ |
| Returns a dict that contains the fields of a message |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| |
| Returns |
| ------- |
| dict: |
| dict message summary |
| """ |
| return { |
| "payload": get_payload(ptr_mbuf) if ptr_mbuf.contents.state == RMR_OK else None, |
| "payload length": ptr_mbuf.contents.len, |
| "message type": ptr_mbuf.contents.mtype, |
| "subscription id": ptr_mbuf.contents.sub_id, |
| "transaction id": get_xaction(ptr_mbuf), |
| "message state": ptr_mbuf.contents.state, |
| "message status": _state_to_status(ptr_mbuf.contents.state), |
| "payload max size": rmr_payload_size(ptr_mbuf), |
| "meid": rmr_get_meid(ptr_mbuf), |
| "message source": get_src(ptr_mbuf), |
| "errno": ptr_mbuf.contents.tp_state, |
| } |
| |
| |
| def set_payload_and_length(byte_str, ptr_mbuf): |
| """ |
| | Set an rmr payload and content length |
| | In place method, no return |
| |
| Parameters |
| ---------- |
| byte_str: bytes |
| the bytes to set the payload to |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| """ |
| if rmr_payload_size(ptr_mbuf) < len(byte_str): # existing message payload too small |
| ptr_mbuf = rmr_realloc_payload(ptr_mbuf, len(byte_str), True) |
| |
| memmove(ptr_mbuf.contents.payload, byte_str, len(byte_str)) |
| ptr_mbuf.contents.len = len(byte_str) |
| |
| |
| def generate_and_set_transaction_id(ptr_mbuf): |
| """ |
| Generate a UUID and Set an rmr transaction id to it |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| """ |
| set_transaction_id(ptr_mbuf, uuid.uuid1().hex.encode("utf-8")) |
| |
| |
| def set_transaction_id(ptr_mbuf, tid_bytes): |
| """ |
| Set an rmr transaction id |
| TODO: on next API break, merge these two functions. Not done now to preserve API. |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| tid_bytes: bytes |
| bytes of the desired transaction id |
| """ |
| sz = _get_constants().get("RMR_MAX_XID", 0) |
| memmove(ptr_mbuf.contents.xaction, tid_bytes, sz) |
| |
| |
| def get_src(ptr_mbuf): |
| """ |
| Get the message source (likely host:port) |
| |
| Parameters |
| ---------- |
| ptr_mbuf: ctypes c_void_p |
| Pointer to an rmr message buffer |
| |
| Returns |
| ------- |
| string: |
| message source |
| """ |
| sz = _get_constants().get("RMR_MAX_SRC", 64) # size to fill |
| buf = create_string_buffer(sz) |
| rmr_get_src(ptr_mbuf, buf) |
| return buf.value.decode() |