Move wrapped C library to subpackage

Create new subpackage rmr/rmrclib with the C library loaded via ctypes.
Add method to get constants from RMR library and detect mock objects.
Split test files into test_rmr and test_rmrclib.
Extend sphinx configuration to mock the rmrclib subpackage, so the
rmr package receives a mock instead of a real object.
This change allows generation of API documentation by Sphinx
when the .so file is not available and import fails, for example
at ReadTheDocs.

Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: Idb9bb1d7a534c4142ea0353b5a48d3132e55f6e6
diff --git a/docs/conf.py b/docs/conf.py
old mode 100644
new mode 100755
index b92d4d9..47e5eb7
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -2,16 +2,22 @@
 import sys
 from docs_conf.conf import *
 
+# autodoc needs this to find the code
 sys.path.insert(0, os.path.abspath("../"))
 
 extensions = ["sphinx.ext.autodoc", "sphinx.ext.viewcode", "numpydoc"]
 
-# dont alphabetically order
+# don't alphabetically order
 autodoc_member_order = "bysource"
 
 linkcheck_ignore = ["http://localhost.*", "http://127.0.0.1.*", "https://gerrit.o-ran-sc.org.*"]
+
+# silence complaints from autodoc gen
 nitpick_ignore = [
             ('py:class', 'ctypes.c_char_p'),
             ('py:class', 'ctypes.c_void_p'),
             ('py:class', 'ricxappframe.rmr.rmr.LP_rmr_mbuf_t'),
             ]
+
+# RMR c library is not available in ReadTheDocs
+autodoc_mock_imports = ['ricxappframe.rmr.rmrclib']
diff --git a/docs/rmr_api.rst b/docs/rmr_api.rst
index 4db5b7e..a33d6a1 100644
--- a/docs/rmr_api.rst
+++ b/docs/rmr_api.rst
@@ -15,1087 +15,12 @@
 RMR API
 -------
 
-..
-  Sphinx can generate API documentation by running Python to pull doc strings
-  from the binding code using these Sphinx directives that are commented out:
-         .. automodule:: ricxappframe.rmr.rmr
-             :members:
-  But that approach requires the RMR library to be installed, which is difficult
-  to achieve at ReadTheDocs.io.  Instead, the RST below was generated and captured
-  according to the method shown at
-  https://stackoverflow.com/questions/2668187/make-sphinx-generate-rst-class-documentation-from-pydoc
+.. automodule:: ricxappframe.rmr.rmr
+    :members:
 
 
+RMR Helper API
+--------------
 
-.. py:module:: ricxappframe.rmr.rmr
-
-
-..
-    !! processed by numpydoc !!
-
-.. py:data:: RMR_MAX_RCV_BYTES
-   :module: ricxappframe.rmr.rmr
-   :value: 65536
-
-
-   Maximum size message to receive
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:data:: RMRFL_MTCALL
-   :module: ricxappframe.rmr.rmr
-   :value: 2
-
-
-   Multi-threaded initialization flag
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:data:: RMRFL_NONE
-   :module: ricxappframe.rmr.rmr
-   :value: 0
-
-
-   Empty flag
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:data:: RMR_OK
-   :module: ricxappframe.rmr.rmr
-   :value: 0
-
-
-   State constant for OK
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:data:: RMR_ERR_TIMEOUT
-   :module: ricxappframe.rmr.rmr
-   :value: 12
-
-
-   State constant for timeout
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:data:: RMR_ERR_RETRY
-   :module: ricxappframe.rmr.rmr
-   :value: 10
-
-
-   State constant for retry
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:class:: rmr_mbuf_t
-   :module: ricxappframe.rmr.rmr
-
-
-   Mirrors public members of type rmr_mbuf_t from RMR 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;
-
-   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.
-
-
-
-
-
-
-
-
-
-
-
-
-
-   :Attributes:
-
-       **len**
-           Structure/Union member
-
-       **mtype**
-           Structure/Union member
-
-       **payload**
-           Structure/Union member
-
-       **state**
-           Structure/Union member
-
-       **sub_id**
-           Structure/Union member
-
-       **tp_state**
-           Structure/Union member
-
-       **xaction**
-           Structure/Union member
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_init(uproto_port: ctypes.c_char_p, max_msg_size: int, flags: int) -> ctypes.c_void_p
-   :module: ricxappframe.rmr.rmr
-
-
-   Prepares the environment for sending and receiving messages.
-   Refer to RMR C documentation for method::
-
-       extern void* rmr_init(char* uproto_port, int max_msg_size, int flags)
-
-   This function raises an exception if the returned context is None.
-
-   :Parameters:
-
-       **uproto_port: c_char_p**
-           Pointer to a buffer with the port number as a string; e.g., "4550"
-
-       **max_msg_size: integer**
-           Maximum message size to receive
-
-       **flags: integer**
-           RMR option flags
-
-   :Returns:
-
-       c_void_p:
-           Pointer to RMR context
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_ready(vctx: ctypes.c_void_p) -> int
-   :module: ricxappframe.rmr.rmr
-
-
-   Checks if a routing table has been received and installed.
-   Refer to RMR C documentation for method::
-
-       extern int rmr_ready(void* vctx)
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-   :Returns:
-
-       1 for yes, 0 for no
-           ..
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_close(vctx: ctypes.c_void_p)
-   :module: ricxappframe.rmr.rmr
-
-
-   Closes the listen socket.
-   Refer to RMR C documentation for method::
-
-       extern void rmr_close(void* vctx)
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-   :Returns:
-
-       None
-           ..
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_set_stimeout(vctx: ctypes.c_void_p, rloops: int) -> int
-   :module: ricxappframe.rmr.rmr
-
-
-   Sets the configuration for how RMR will retry message send operations.
-   Refer to RMR C documentation for method::
-
-       extern int rmr_set_stimeout(void* vctx, int rloops)
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-       **rloops: int**
-           Number of retry loops
-
-   :Returns:
-
-       0 on success, -1 on failure
-           ..
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_alloc_msg(vctx: ctypes.c_void_p, size: int, payload=None, gen_transaction_id: bool = False, mtype=None, meid=None, sub_id=None, fixed_transaction_id=None)
-   :module: ricxappframe.rmr.rmr
-
-
-   Allocates and returns a buffer to write and send through the RMR library.
-   Refer to RMR C documentation for method::
-
-       extern rmr_mbuf_t* rmr_alloc_msg(void* vctx, int size)
-
-   Optionally populates the message from the remaining arguments.
-
-   TODO: on next API break, clean up transaction_id ugliness. Kept for now to preserve API.
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-       **size: int**
-           How much space to allocate
-
-       **payload: bytes**
-           if not None, attempts to set the payload
-
-       **gen_transaction_id: bool**
-           if True, generates and sets a transaction ID.
-           Note, option fixed_transaction_id overrides this option
-
-       **mtype: bytes**
-           if not None, sets the sbuf's message type
-
-       **meid: bytes**
-           if not None, sets the sbuf's meid
-
-       **sub_id: bytes**
-           if not None, sets the sbuf's subscription id
-
-       **fixed_transaction_id: bytes**
-           if not None, used as the transaction ID.
-           Note, this overrides the option gen_transaction_id
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_realloc_payload(ptr_mbuf: ctypes.c_void_p, new_len: int, copy: bool = False, clone: bool = False)
-   :module: ricxappframe.rmr.rmr
-
-
-   Allocates and returns a message buffer large enough for the new length.
-   Refer to RMR C documentation for method::
-
-       extern rmr_mbuf_t* rmr_realloc_payload(rmr_mbuf_t*, int, int, int)
-
-   :Parameters:
-
-       **ptr_mbuf: c_void_p**
-           Pointer to rmr_mbuf structure
-
-       **new_len: int**
-           Length
-
-       **copy: bool**
-           Whether to copy the original paylod
-
-       **clone: bool**
-           Whether to clone the original buffer
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_free_msg(ptr_mbuf: ctypes.c_void_p)
-   :module: ricxappframe.rmr.rmr
-
-
-   Releases the message buffer.
-   Refer to RMR C documentation for method::
-
-       extern void rmr_free_msg(rmr_mbuf_t* mbuf )
-
-   :Parameters:
-
-       **ptr_mbuf: c_void_p**
-           Pointer to rmr_mbuf structure
-
-   :Returns:
-
-       None
-           ..
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_payload_size(ptr_mbuf: ctypes.c_void_p) -> int
-   :module: ricxappframe.rmr.rmr
-
-
-   Gets the number of bytes available in the payload.
-   Refer to RMR C documentation for method::
-
-       extern int rmr_payload_size(rmr_mbuf_t* msg)
-
-   :Parameters:
-
-       **ptr_mbuf: c_void_p**
-           Pointer to rmr_mbuf structure
-
-   :Returns:
-
-       int:
-           Number of bytes available
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_send_msg(vctx: ctypes.c_void_p, ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t) -> ricxappframe.rmr.rmr.LP_rmr_mbuf_t
-   :module: ricxappframe.rmr.rmr
-
-
-   Sends the message according to the routing table and returns an empty buffer.
-   Refer to RMR C documentation for method::
-
-       extern rmr_mbuf_t* rmr_send_msg(void* vctx, rmr_mbuf_t* msg)
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-       **ptr_mbuf: c_void_p**
-           Pointer to rmr_mbuf structure
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_rcv_msg(vctx: ctypes.c_void_p, ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t) -> ricxappframe.rmr.rmr.LP_rmr_mbuf_t
-   :module: ricxappframe.rmr.rmr
-
-
-   Waits for a message to arrive, and returns it.
-   Refer to RMR C documentation for method::
-
-       extern rmr_mbuf_t* rmr_rcv_msg(void* vctx, rmr_mbuf_t* old_msg)
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-       **ptr_mbuf: c_void_p**
-           Pointer to rmr_mbuf structure
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_torcv_msg(vctx: ctypes.c_void_p, ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t, ms_to: int) -> ricxappframe.rmr.rmr.LP_rmr_mbuf_t
-   :module: ricxappframe.rmr.rmr
-
-
-   Waits up to the timeout value for a message to arrive, and returns it.
-   Refer to RMR C documentation for method::
-
-       extern rmr_mbuf_t* rmr_torcv_msg(void* vctx, rmr_mbuf_t* old_msg, int ms_to)
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to RMR context
-
-       **ptr_mbuf: c_void_p**
-           Pointer to rmr_mbuf structure
-
-       **ms_to: int**
-           Time out value in milliseconds
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_rts_msg(vctx: ctypes.c_void_p, ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t, payload=None, mtype=None) -> ricxappframe.rmr.rmr.LP_rmr_mbuf_t
-   :module: ricxappframe.rmr.rmr
-
-
-   Sends a message to the originating endpoint and returns an empty buffer.
-   Refer to RMR C documentation for method::
-
-       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
-
-   :Parameters:
-
-       **vctx: ctypes c_void_p**
-           Pointer to an RMR context
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an RMR message buffer
-
-       **payload: bytes**
-           Payload
-
-       **mtype: bytes**
-           Message type
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_call(vctx: ctypes.c_void_p, ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t) -> ricxappframe.rmr.rmr.LP_rmr_mbuf_t
-   :module: ricxappframe.rmr.rmr
-
-
-   Sends a message, waits for a response and returns it.
-   Refer to RMR C documentation for method::
-
-       extern rmr_mbuf_t* rmr_call(void* vctx, rmr_mbuf_t* msg)
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an RMR message buffer
-
-   :Returns:
-
-       c_void_p:
-           Pointer to rmr_mbuf structure
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_set_meid(ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t, byte_str: bytes) -> int
-   :module: ricxappframe.rmr.rmr
-
-
-   Sets the managed entity field in the message and returns the number of bytes copied.
-   Refer to RMR C documentation for method::
-
-       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
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an RMR message buffer
-
-       **byte_tr: bytes**
-           Managed entity ID value
-
-   :Returns:
-
-       int:
-           number of bytes copied
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_get_meid(ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t) -> bytes
-   :module: ricxappframe.rmr.rmr
-
-
-   Gets the managed entity ID (meid) from the message header.
-   This is a python-friendly version of RMR C method::
-
-       extern unsigned char* rmr_get_meid(rmr_mbuf_t* mbuf, unsigned char* dest);
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an RMR message buffer
-
-   :Returns:
-
-       bytes:
-           Managed entity ID
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: rmr_get_src(ptr_mbuf: ricxappframe.rmr.rmr.LP_rmr_mbuf_t, dest: ctypes.c_char_p) -> ctypes.c_char_p
-   :module: ricxappframe.rmr.rmr
-
-
-   Copies the message-source information to the buffer.
-   Refer to RMR C documentation for method::
-
-       extern unsigned char* rmr_get_src(rmr_mbuf_t* mbuf, unsigned char* dest);
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes POINTER(rmr_mbuf_t)**
-           Pointer to an RMR message buffer
-
-       **dest: ctypes c_char_p**
-           Pointer to a buffer to receive the message source
-
-   :Returns:
-
-       string:
-           message-source information
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: get_payload(ptr_mbuf: ctypes.c_void_p) -> bytes
-   :module: ricxappframe.rmr.rmr
-
-
-   Gets the binary payload from the rmr_buf_t*.
-
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an rmr message buffer
-
-   :Returns:
-
-       bytes:
-           the message payload
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: get_xaction(ptr_mbuf: ctypes.c_void_p) -> bytes
-   :module: ricxappframe.rmr.rmr
-
-
-   Gets the transaction ID from the rmr_buf_t*.
-
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an rmr message buffer
-
-   :Returns:
-
-       bytes:
-           the transaction id
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: message_summary(ptr_mbuf: ctypes.c_void_p) -> dict
-   :module: ricxappframe.rmr.rmr
-
-
-   Returns a dict with the fields of an RMR message.
-
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an rmr message buffer
-
-   :Returns:
-
-       dict:
-           dict message summary
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: set_payload_and_length(byte_str: bytes, ptr_mbuf: ctypes.c_void_p)
-   :module: ricxappframe.rmr.rmr
-
-
-   Sets 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
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: generate_and_set_transaction_id(ptr_mbuf: ctypes.c_void_p)
-   :module: ricxappframe.rmr.rmr
-
-
-   Generates a UUID and sets the RMR transaction id to it
-
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an rmr message buffer
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: set_transaction_id(ptr_mbuf: ctypes.c_void_p, tid_bytes: bytes)
-   :module: ricxappframe.rmr.rmr
-
-
-   Sets 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
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
-.. py:function:: get_src(ptr_mbuf: ctypes.c_void_p) -> str
-   :module: ricxappframe.rmr.rmr
-
-
-   Gets the message source (likely host:port)
-
-
-   :Parameters:
-
-       **ptr_mbuf: ctypes c_void_p**
-           Pointer to an rmr message buffer
-
-   :Returns:
-
-       string:
-           message source
-
-
-
-
-
-
-
-
-
-
-
-
-
-   ..
-       !! processed by numpydoc !!
-
+.. automodule:: ricxappframe.rmr.helpers
+    :members:
diff --git a/ricxappframe/rmr/rmr.py b/ricxappframe/rmr/rmr.py
index 80617a7..e29a5de 100644
--- a/ricxappframe/rmr/rmr.py
+++ b/ricxappframe/rmr/rmr.py
@@ -15,107 +15,48 @@
 #   limitations under the License.
 # ==================================================================================
 import uuid
-import json
-from ctypes import CDLL, POINTER, RTLD_GLOBAL, Structure
-from ctypes import c_char, c_char_p, c_int, c_void_p, cast, create_string_buffer, memmove
+from ctypes import POINTER, Structure
+from ctypes import c_int, c_char, c_char_p, c_void_p, memmove, cast, create_string_buffer
 
 from ricxappframe.rmr.exceptions import BadBufferAllocation, MeidSizeOutOfRange, InitFailed
+from ricxappframe.rmr.rmrclib.rmrclib import rmr_c_lib, get_constants, state_to_status
 
-# 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/;
-rmr_c_lib = CDLL("librmr_si.so", mode=RTLD_GLOBAL)
+##############
+# PRIVATE API
+##############
 
 
-# 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={}) -> dict:
+def _get_rmr_constant(key: str, default=None):
     """
-    Gets constants published by RMR and caches for subsequent calls.
-    TODO: are there constants that end user applications need?
+    Gets the constant with the named key from the RMR C library.
+    Returns None if the value is not a simple type. This happens
+    during sphinx autodoc document generation, which mocks the
+    rmrclib package to work without the RMR shared object file,
+    and the response is something like this:
+    <class 'ricxappframe.rmr.rmrclib.rmrclib.get_constants.get'>
     """
-    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={}) -> dict:
-    """
-    Builds a state mapping dict from constants and caches for subsequent calls.
-    Relevant constants at this writing include:
-
-    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: int) -> str:
-    """
-    Converts a msg state integer to a status string.
-    Returns "UNKNOWN STATE" if the int value is not known.
-
-    """
-    sdict = _get_mapping_dict()
-    return sdict.get(stateno, "UNKNOWN STATE")
-
-
-_RCONST = _get_constants()
+    val = get_constants().get(key, default)
+    return val if isinstance(val, (type(None), bool, bytes, float, int, str)) else None
 
 
 ##############
 # PUBLIC API
 ##############
 
-
-# These constants are directly usable by importers of this library
+# Publish constants from RMR C-language header files for use by importers of this library.
 # TODO: Are there others that will be useful?
-
-#: Maximum size message to receive
-RMR_MAX_RCV_BYTES = _RCONST["RMR_MAX_RCV_BYTES"]
+#: Typical size message to receive; size is not limited
+RMR_MAX_RCV_BYTES = _get_rmr_constant('RMR_MAX_RCV_BYTES')
 #: Multi-threaded initialization flag
-RMRFL_MTCALL = _RCONST.get("RMRFL_MTCALL", 0x02)  # initialization flags
+RMRFL_MTCALL = _get_rmr_constant('RMRFL_MTCALL', 0x02)  # initialization flags
 #: Empty flag
-RMRFL_NONE = _RCONST.get("RMRFL_NONE", 0x0)
+RMRFL_NONE = _get_rmr_constant('RMRFL_NONE', 0x0)
 #: State constant for OK
-RMR_OK = _RCONST["RMR_OK"]
+RMR_OK = _get_rmr_constant('RMR_OK', 0x00)
 #: State constant for timeout
-RMR_ERR_TIMEOUT = _RCONST["RMR_ERR_TIMEOUT"]
+RMR_ERR_TIMEOUT = _get_rmr_constant('RMR_ERR_TIMEOUT')
 #: State constant for retry
-RMR_ERR_RETRY = _RCONST["RMR_ERR_RETRY"]
+RMR_ERR_RETRY = _get_rmr_constant('RMR_ERR_RETRY')
 
 
 class rmr_mbuf_t(Structure):
@@ -160,8 +101,6 @@
 
 
 # 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
@@ -607,7 +546,7 @@
     int:
         number of bytes copied
     """
-    max = _get_constants().get("RMR_MAX_MEID", 32)
+    max = _get_rmr_constant("RMR_MAX_MEID", 32)
     if len(byte_str) >= max:
         raise MeidSizeOutOfRange
 
@@ -643,7 +582,7 @@
     bytes:
         Managed entity ID
     """
-    sz = _get_constants().get("RMR_MAX_MEID", 32)  # size for buffer to fill
+    sz = _get_rmr_constant("RMR_MAX_MEID", 32)  # size for buffer to fill
     buf = create_string_buffer(sz)
     _rmr_get_meid(ptr_mbuf, buf)
     return buf.value
@@ -715,7 +654,7 @@
         the transaction id
     """
     val = cast(ptr_mbuf.contents.xaction, c_char_p).value
-    sz = _get_constants().get("RMR_MAX_XID", 0)
+    sz = _get_rmr_constant("RMR_MAX_XID", 0)
     return val[:sz]
 
 
@@ -740,7 +679,7 @@
         "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),
+        "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),
@@ -794,7 +733,7 @@
     tid_bytes: bytes
         bytes of the desired transaction id
     """
-    sz = _get_constants().get("RMR_MAX_XID", 0)
+    sz = _get_rmr_constant("RMR_MAX_XID", 0)
     memmove(ptr_mbuf.contents.xaction, tid_bytes, sz)
 
 
@@ -812,7 +751,7 @@
     string:
         message source
     """
-    sz = _get_constants().get("RMR_MAX_SRC", 64)  # size to fill
+    sz = _get_rmr_constant("RMR_MAX_SRC", 64)  # size to fill
     buf = create_string_buffer(sz)
     rmr_get_src(ptr_mbuf, buf)
     return buf.value.decode()
diff --git a/ricxappframe/rmr/rmrclib/__init__.py b/ricxappframe/rmr/rmrclib/__init__.py
new file mode 100644
index 0000000..a1dc889
--- /dev/null
+++ b/ricxappframe/rmr/rmrclib/__init__.py
@@ -0,0 +1,16 @@
+# ==================================================================================
+#       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.
+# ==================================================================================
diff --git a/ricxappframe/rmr/rmrclib/rmrclib.py b/ricxappframe/rmr/rmrclib/rmrclib.py
new file mode 100644
index 0000000..ad770ab
--- /dev/null
+++ b/ricxappframe/rmr/rmrclib/rmrclib.py
@@ -0,0 +1,88 @@
+# ==================================================================================
+#       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 ctypes
+import json
+
+# Subpackage that creates and publishes a reference to the C shared library.
+# Intended to be private; RMR-python and xapp-frame-py users should not need this.
+# Sphinx and autodoc mock this module to run without the .so file present.
+
+# 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/;
+rmr_c_lib = ctypes.CDLL("librmr_si.so", mode=ctypes.RTLD_GLOBAL)
+_rmr_get_consts = rmr_c_lib.rmr_get_consts
+_rmr_get_consts.argtypes = []
+_rmr_get_consts.restype = ctypes.c_char_p
+
+
+def get_constants(cache={}):
+    """
+    Gets constants published by RMR and caches for subsequent calls.
+    TODO: are there constants that end user applications need?
+    """
+    if cache:
+        return cache
+
+    js = _rmr_get_consts()  # read json string
+    cache = json.loads(str(js.decode()))  # create constants value object as a hash
+    return cache
+
+
+def get_mapping_dict(cache={}):
+    """
+    Builds a state mapping dict from constants and caches for subsequent calls.
+    Relevant constants at this writing include:
+
+    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):
+    """
+    Converts a msg state integer to a status string.
+
+    Returns "UNKNOWN STATE" if the int value is not known.
+    """
+    sdict = get_mapping_dict()
+    return sdict.get(stateno, "UNKNOWN STATE")
diff --git a/tests/test_rmr.py b/tests/test_rmr.py
index a503968..afd9980 100644
--- a/tests/test_rmr.py
+++ b/tests/test_rmr.py
@@ -68,38 +68,6 @@
     assert summary["errno"] == 0
 
 
-def test_get_constants(expected_constants):
-    """
-    test getting constants. We don't care what values are returned as those
-    should be meaningful only to RMR. We do care that all of the constants
-    which are defined in expected_contents are returned.  Further, we don't
-    consider it to be an error if the returned list has more constants than
-    what are in our list.
-
-    To avoid frustration, this should list all missing keys, not fail on the
-    first missing key.
-    """
-    errors = 0
-    econst = expected_constants
-    rconst = rmr._get_constants()
-    for key in econst:  # test all expected constants
-        if key not in rconst:  # expected value not listed by rmr
-            errors += 1
-            print("did not find required constant in list from RMR: %s" % key)
-
-    assert errors == 0
-
-
-def test_get_mapping_dict(expected_states):
-    """
-    test getting mapping string
-    """
-    assert rmr._get_mapping_dict() == expected_states
-    assert rmr._state_to_status(0) == "RMR_OK"
-    assert rmr._state_to_status(12) == "RMR_ERR_TIMEOUT"
-    assert rmr._state_to_status(666) == "UNKNOWN STATE"
-
-
 def test_meid():
     """
     test meid stringification
diff --git a/tests/test_rmrclib.py b/tests/test_rmrclib.py
new file mode 100644
index 0000000..eba4436
--- /dev/null
+++ b/tests/test_rmrclib.py
@@ -0,0 +1,49 @@
+# =================================================================================2
+#       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.
+# ==================================================================================
+from ricxappframe.rmr.rmrclib import rmrclib
+
+
+def test_get_constants(expected_constants):
+    """
+    test getting constants. We don't care what values are returned as those
+    should be meaningful only to RMR. We do care that all of the constants
+    which are defined in expected_contents are returned.  Further, we don't
+    consider it to be an error if the returned list has more constants than
+    what are in our list.
+
+    To avoid frustration, this should list all missing keys, not fail on the
+    first missing key.
+    """
+    errors = 0
+    econst = expected_constants
+    rconst = rmrclib.get_constants()
+    for key in econst:  # test all expected constants
+        if key not in rconst:  # expected value not listed by rmr
+            errors += 1
+            print("did not find required constant in list from RMR: %s" % key)
+
+    assert errors == 0
+
+
+def test_get_mapping_dict(expected_states):
+    """
+    test getting mapping string
+    """
+    assert rmrclib.get_mapping_dict() == expected_states
+    assert rmrclib.state_to_status(0) == "RMR_OK"
+    assert rmrclib.state_to_status(12) == "RMR_ERR_TIMEOUT"
+    assert rmrclib.state_to_status(666) == "UNKNOWN STATE"