Py-Interface

Description

The Py-Interface is a python-implementation of an Erlang node.

The py_interface provides the possibility to create a node that may be used for communication with other Erlang nodes.

Some characteristics:

• The Python nodes are hidden, like the Java nodes
• The Python node supports
  • registering the Python node in the epmd
  • sending and receiving message
  • executing remote procedure calls (the rpc:call(M,F,A) mechanism)
• The Python node does currently not do:
  • linking
  • tracing
• The Python node translates Erlang types to Python types as far as there is a reasonable Python counterpart. If there is not, then a class is used.
• The Python node is a single threaded callback-driven process.
• The Python node was last tested on Python 2.7.2+ and Erlang 17.0. It may well still work with older version of both Python and Erlang. Development started on Python 1.5 and Erlang R7.
• The source of information for this Python node has been the files `distribution_handshake.txt' and `erl_ext_dist.txt' together with the Java node source files, the `net_kernel.erl' and the `dist_util.erl' files in the Erlang source code distribution.

Screenshot (well, sort of)

Here's a screenshot of one of the test programs (since the main code is a library, it doesn't look like anything at all on a picture :-)

Download

Download the latest version: py_interface-2.3.tar.gz.

Py-Interface is written entirely in Python, for communication with Erlang so you need to have Python and Erlang installed, to use it.

Development

A git repository is hosted at github. To clone it, run:

   git clone git://github.com/tomas-abrahamsson/py_interface.git

Known bugs

Probably a few.

Authors

Tomas Abrahamsson <tab@lysator.liu.se>, with great help from David King, Ed Blake, Luke Gorrie, Jimmy Olgeni, Nigel Head, Paul "TBBle" Hampson, bird devdoer, David Reiss, Anton Krasovsky and HP Wei. (I hope I haven't forgotten anyone; please let me know if that's the case.)

Licensing

Py-Interface is distributed under the GNU Library General Public License.

History

version 2.3, 2018-Jan-03 py_interface-2.3.tar.gz

Allow to specify Epmd host and port number through ErlNodeOpts. Thanks to Dmitry Shestak

version 2.2, 2017-Jul-11 py_interface-2.2.tar.gz

Adapt to Erlang 20.

version 2.1, 2017-Jan-11 py_interface-2.1.tar.gz

Changes:

• Bugfix unpacking of strings
• Change type of binaries from ErlBinary to bytes
• New utilities erl_term.IODataToStr and erl_term.StrToList

version 2.0, 2017-Jan-07 py_interface-2.0.tar.gz

Python 3 support (only). Dropped support for Python 2. (The changes to the packing and unpacking code, mostly, were too pervasive, to support both Python 2 an 3 in the same code base.)

version 1.4, 2017-Jan-07 py_interface-1.4.tar.gz

NB: this is the last version with support for Python 2. From 2.0 it is Python 3. Bugfixes might go into 1.4.x, if important enough, but any new development is intended for Python 3 only.

• Bugfix packing of improper lists
• In the ErlMap type (a dict), make ints and floats differ since this is how the corresponding map is on the Erlang side. This differ from normal Python dicts.
• Rework the homebrewn tests into Python and Erlang unit tests

version 1.3, 2014-Apr-25 py_interface-1.3.tar.gz

Several enhancements:

• Add support for encoding of new floats (8 bytes)
• Add support for encoding of bit strings
• Add support for exports (fun M:F/A)
• Add support for funs (fun(...) -> ... end, and fun X/A)
• Encode/decode depending on the peer's advertised distr flags
• Convert exceptions from old-style deprecated strings, to classes

version 1.2.1, 2014-Apr-21 py_interface-1.2.1.tar.gz

Fix a bug in the 'dist' top-level make target

version 1.2, 2014-Apr-21

Add support for Erlang 17.0 maps. (note that the external term format for maps differs in the final 17.0 from that in 17.0-rc1 and 17.0-rc2)

version 1.1.1, 2011-Mar-15 py_interface-1.1.1.tar.gz

Some example files that were new in 1.1 were not included in the tar ball. They were available only via the git repository. Now these files are in the tar ball as well:

• examples/run_remote_exec_wrapper.sh
• examples/test_remote_exec.py
• examples/run_test_erl_node_pingpong_qc.sh
• examples/test_erl_node_pingpong_qc.erl

version 1.1, 2011-Feb-22 py_interface-1.1.tar.gz

Changes:

• Bugfix: now handles incoming packets larger than 64kbytes
• New example examples/run_remote_exec_wrapper.sh, which is a bit similar to what erl_call does, after an idea by HP Wei.
• New QuickCheck test for pingpong sending of data, see examples/test_erl_node_pingpong_qc.sh. This is how I found the large packets bug mentioned above. Works with the eqcmini, which at the time of this writing is eqcmini-1.0.1.

version 1.0, 2010-Apr-13 py_interface-1.0.tar.gz

Changes: Applied a patch by Paul "TBBle" Hampson: Erlang/OTP epmd R13B04 compatibility: R13B04 fixed a bug in the epmd's handling of the `extra' field. This patch makes py_interface work with the bug-fixed epmd.

version 0.99, 2010-Mar-30 py_interface-0.99.tar.gz

Changes: Bugfix of call to _HexDumpFormat in DebugHex. Reported by Paul "TBBle" Hampson.

version 0.98, 2009-Nov-18 py_interface-0.98.tar.gz

Changes: Bugfix for handling negative integers, reported by bird devdoer.

version 0.97, 2009-Jul-27 py_interface-0.97.tar.gz

Changes:

• py_interface/erl_eventhandler.py: handles interrupted system call exceptions also in the timeout case.
• py_interface/erl_node.py: doc string fix for methods ErlMBox.Send and ErlNode.SendMsgFromMBox: the order of the process name and node name had gotten mixed up. Noted by Paul TBBle Hampson.
• py_interface/erl_node_conn.py: Python 2.6 compatibility patch by David Reiss applied: uses md5 from hashlib if that one is available.

version 0.96, 2008-Dec-17 py_interface-0.96.tar.gz

Changes: Applied two patches from Anton Krasovsky: fixes for programming errors triggered by internode communication failures.
Also fixed is version number propagation to all files, and building problems: the tar file now contains all files necessary to build the package.

version 0.95, 2008-Jul-15 py_interface-0.95.tar.gz

Changes: Applied patch from David King: the socket connection now also checks for EWOULDBLOCK. Previously it only checked for EAGAIN.

version 0.94, 2008-Jul-13 py_interface-0.94.tar.gz

Changes: Applied patches and bugfixes from David King:

• The code now resides in its own namespace: py_interface
• Now supports packaging as an easy_install egg
• Bugfix: Queued writes attempted to access an undefined variable.

version 0.93, 2006-Jul-25 py_interface-0.93.tar.gz

Changes:

• Updated to work with Erlang R10 and R11 (15-->28 bits in pids and ports).
• Now also works with threaded Tcl (as with Debian) as well.
• Also fixed a deprecation issue: integer vs floating-point timeout values in erl_event_handler.py.
• Also added an installation support (the __init__.py file), based on information by Ed Blake.

version 0.92, 2004-Jul-13 py_interface-0.92.tar.gz

Several bugfixes in packing/unpacking of erlang terms. A lot of thanks to Jimmy Olgeni and Nigel Head for patches. See the file erl_term.py, in the tar file, for details.

version 0.91, 2002-Jul-21 py_interface-0.91.tar.gz

Added autoconf stuff. This version is/was also on the Erlang User contribution page

version 0.9, 2002-May-29 py_interface-0.9.tar.gz

First version

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