-# 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 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()