--- /dev/null
+# ==================================================================================
+# Copyright (c) 2019 Nokia
+# Copyright (c) 2018-2019 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, pythonapi
+
+# 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
+_ = CDLL("libnng.so", mode=RTLD_GLOBAL)
+rmr_c_lib = CDLL("librmr_nng.so", mode=RTLD_GLOBAL)
+
+
+_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
+
+ #define RMR_OK 0 // state is good
+ #define RMR_ERR_BADARG 1 // argument passd to function was unusable
+ #define RMR_ERR_NOENDPT 2 // send/call could not find an endpoint based on msg type
+ #define RMR_ERR_EMPTY 3 // msg received had no payload; attempt to send an empty message
+ #define RMR_ERR_NOHDR 4 // message didn't contain a valid header
+ #define RMR_ERR_SENDFAILED 5 // send failed; errno has nano reason
+ #define RMR_ERR_CALLFAILED 6 // unable to send call() message
+ #define RMR_ERR_NOWHOPEN 7 // no wormholes are open
+ #define RMR_ERR_WHID 8 // wormhole id was invalid
+ #define RMR_ERR_OVERFLOW 9 // operation would have busted through a buffer/field size
+ #define RMR_ERR_RETRY 10 // request (send/call/rts) failed, but caller should retry (EAGAIN for wrappers)
+ #define RMR_ERR_RCVFAILED 11 // receive failed (hard error)
+ #define RMR_ERR_TIMEOUT 12 // message processing call timed out
+ #define RMR_ERR_UNSET 13 // the message hasn't been populated with a transport buffer
+ #define RMR_ERR_TRUNC 14 // received message likely truncated
+ #define RMR_ERR_INITFAILED 15 // initialisation 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):
+ """
+ convery a msg state to status
+ """
+ sdict = _get_mapping_dict()
+ return sdict.get(stateno, "UNKNOWN STATE")
+
+
+def _errno():
+ """Suss out the C error number value which might be useful in understanding
+ an underlying reason when RMr returns a failure.
+ """
+ return c_int.in_dll(pythonapi, "errno").value
+
+
+##############
+# PUBLIC API
+##############
+
+# These constants are directly usable by importers of this library
+# TODO: Are there others that will be useful?
+RMR_MAX_RCV_BYTES = _get_constants()["RMR_MAX_RCV_BYTES"]
+
+
+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
+ // 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),
+ ]
+
+
+# argtypes and restype are important: https://stackoverflow.com/questions/24377845/ctype-why-specify-argtypes
+
+
+# extern void* rmr_init(char* uproto_port, int max_msg_size, int flags)
+rmr_init = rmr_c_lib.rmr_init
+rmr_init.argtypes = [c_char_p, c_int, c_int]
+rmr_init.restype = c_void_p
+
+
+# extern void rmr_close(void* vctx)
+rmr_close = rmr_c_lib.rmr_close
+rmr_close.argtypes = [c_void_p]
+# I don't think there's a restype needed here. THe return is simply "return" in the c lib
+
+# extern int rmr_ready(void* vctx)
+rmr_ready = rmr_c_lib.rmr_ready
+rmr_ready.argtypes = [c_void_p]
+rmr_ready.restype = c_int
+
+# extern int rmr_set_stimeout(void* vctx, int time)
+# RE "int time", from the C docs:
+# Set send timeout. The value time is assumed to be microseconds. The timeout is the
+# rough maximum amount of time that RMr will block on a send attempt when the underlying
+# mechnism indicates eagain or etimeedout. All other error conditions are reported
+# without this delay. Setting a timeout of 0 causes no retries to be attempted in
+# RMr code. Setting a timeout of 1 causes RMr to spin up to 10K retries before returning,
+# but without issuing a sleep. If timeout is > 1, then RMr will issue a sleep (1us)
+# after every 10K send attempts until the time value is reached. Retries are abandoned
+# if NNG returns anything other than NNG_AGAIN or NNG_TIMEDOUT.
+#
+# The default, if this function is not used, is 1; meaning that RMr will retry, but will
+# not enter a sleep. In all cases the caller should check the status in the message returned
+# after a send call.
+rmr_set_stimeout = rmr_c_lib.rmr_set_rtimeout
+rmr_set_stimeout.argtypes = [c_void_p, c_int]
+rmr_set_stimeout.restype = c_int
+
+# extern rmr_mbuf_t* rmr_alloc_msg(void* vctx, int size)
+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)
+
+# extern int rmr_payload_size(rmr_mbuf_t* msg)
+rmr_payload_size = rmr_c_lib.rmr_payload_size
+rmr_payload_size.argtypes = [POINTER(rmr_mbuf_t)]
+rmr_payload_size.restype = c_int
+
+
+"""
+The following functions all seem to have the same interface
+"""
+
+# extern rmr_mbuf_t* rmr_send_msg(void* vctx, rmr_mbuf_t* msg)
+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)
+
+# extern rmr_mbuf_t* rmr_rcv_msg(void* vctx, rmr_mbuf_t* old_msg)
+# 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)
+
+# extern rmr_mbuf_t* rmr_torcv_msg(void* vctx, rmr_mbuf_t* old_msg, int ms_to)
+# the version of receive for nng that has a timeout (give up after X ms)
+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)
+
+# extern rmr_mbuf_t* rmr_rts_msg(void* vctx, rmr_mbuf_t* msg)
+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)
+
+# extern rmr_mbuf_t* rmr_call(void* vctx, rmr_mbuf_t* msg)
+rmr_call = rmr_c_lib.rmr_call
+rmr_call.argtypes = [c_void_p, POINTER(rmr_mbuf_t)]
+rmr_call.restype = POINTER(rmr_mbuf_t)
+
+
+# Header field interface
+
+# extern int rmr_bytes2meid(rmr_mbuf_t* mbuf, unsigned char const* src, int len);
+rmr_bytes2meid = rmr_c_lib.rmr_bytes2meid
+rmr_bytes2meid.argtypes = [POINTER(rmr_mbuf_t), c_char_p, c_int]
+rmr_bytes2meid.restype = c_int
+
+
+# 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);
+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
+
+# extern unsigned char* rmr_get_src(rmr_mbuf_t* mbuf, unsigned char* dest);
+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
+
+
+# GET Methods
+
+
+def get_payload(ptr_to_rmr_buf_t):
+ """
+ given a rmr_buf_t*, get it's binary payload as a bytes object
+ this magical function came from the answer here: https://stackoverflow.com/questions/55103298/python-ctypes-read-pointerc-char-in-python
+ """
+ sz = ptr_to_rmr_buf_t.contents.len
+ CharArr = c_char * sz
+ return CharArr(*ptr_to_rmr_buf_t.contents.payload[:sz]).raw
+
+
+def get_xaction(ptr_to_rmr_buf_t):
+ """
+ given a rmr_buf_t*, get it's transaction id
+ """
+ val = cast(ptr_to_rmr_buf_t.contents.xaction, c_char_p).value
+ sz = _get_constants().get("RMR_MAX_XID", 0)
+ return val[:sz]
+
+
+def message_summary(ptr_to_rmr_buf_t):
+ """
+ Used for debugging mostly: returns a dict that contains the fields of a message
+ """
+ if ptr_to_rmr_buf_t.contents.len > RMR_MAX_RCV_BYTES:
+ return "Malformed message: message length is greater than the maximum possible"
+
+ meid = get_meid(ptr_to_rmr_buf_t)
+ if meid == "\000" * _get_constants().get("RMR_MAX_MEID", 32): # special case all nils
+ meid = None
+
+ return {
+ "payload": get_payload(ptr_to_rmr_buf_t),
+ "payload length": ptr_to_rmr_buf_t.contents.len,
+ "message type": ptr_to_rmr_buf_t.contents.mtype,
+ "subscription id": ptr_to_rmr_buf_t.contents.sub_id,
+ "transaction id": get_xaction(ptr_to_rmr_buf_t),
+ "message state": ptr_to_rmr_buf_t.contents.state,
+ "message status": _state_to_status(ptr_to_rmr_buf_t.contents.state),
+ "payload max size": rmr_payload_size(ptr_to_rmr_buf_t),
+ "meid": meid,
+ "message source": get_src(ptr_to_rmr_buf_t),
+ "errno": _errno(),
+ }
+
+
+def set_payload_and_length(byte_str, ptr_to_rmr_buf_t):
+ """
+ use memmove to set the rmr_buf_t payload and content length
+ """
+ memmove(ptr_to_rmr_buf_t.contents.payload, byte_str, len(byte_str))
+ ptr_to_rmr_buf_t.contents.len = len(byte_str)
+
+
+def generate_and_set_transaction_id(ptr_to_rmr_buf_t):
+ """
+ use memmove to set the rmr_buf_t xaction
+ """
+ uu_id = uuid.uuid1().hex.encode("utf-8")
+ sz = _get_constants().get("RMR_MAX_XID", 0)
+ memmove(ptr_to_rmr_buf_t.contents.xaction, uu_id, sz)
+
+
+def get_meid(mbuf):
+ """
+ Suss out the managed equipment ID (meid) from the message header.
+ This is a 32 byte field and RMr returns all 32 bytes which if the
+ sender did not set will be garbage.
+ """
+ sz = _get_constants().get("RMR_MAX_MEID", 64) # size for buffer to fill
+ buf = create_string_buffer(sz)
+ rmr_get_meid(mbuf, buf)
+ return buf.raw.decode()
+
+
+def get_src(mbuf):
+ """
+ Suss out the message source information (likely host:port).
+ """
+ sz = _get_constants().get("RMR_MAX_SRC", 64) # size to fill
+ buf = create_string_buffer(sz)
+ rmr_get_src(mbuf, buf)
+ return buf.value.decode()
Code Review / ric-plt / lib / rmr.git / blobdiff