[65] GraphViz's executables not found on Windows 7 64-bit

[prmtl]

What steps will reproduce the problem?

1. Install pydot on Win 7 64
2. Try to run the graph write_png() method

What is the expected output? What do you see instead?

You'll see this:
graph.write_png('example2_graph.png')
File "build\bdist.win-amd64\egg\pydot.py", line 1809, in
File "build\bdist.win-amd64\egg\pydot.py", line 1911, in write
File "build\bdist.win-amd64\egg\pydot.py", line 1953, in create
pydot.InvocationException: GraphViz's executables not found

What version of the product are you using? On what operating system?

Using graphviz 2.28 on Win 7 64-bit.

Please provide any additional information below.

It looks like graphviz uses a different registry setting for Win7 64:

hkey = win32api.RegOpenKeyEx( win32con.HKEY_LOCAL_MACHINE, "SOFTWARE\Wow6432Node\AT&T Research Labs\Graphviz 2.28", 0, win32con.KEY_QUERY_VALUE )

From: https://code.google.com/p/pydot/issues/detail?id=65
Reported by mike.naq...@gmail.com, Jan 20, 2012

[prmtl]

mike.naq...@gmail.com, Jan 20, 2012
Adding to the potentialKeys works, but I'm not sure how easy this will be to maintain.

        hkey = None
        potentialKeys = [
            "SOFTWARE\\ATT\\Graphviz",
            "SOFTWARE\\AT&T Research Labs\\Graphviz",
            "SOFTWARE\\Wow6432Node\\AT&T Research Labs\\Graphviz 2.28",
        ]

[prmtl]

edeussil...@gmail.com, Feb 13, 2012
Hi mike.naq,

I am unfamiliar with the inner workings of Python. Where can I find this reference to potentialKeys, so I can edit it?

[prmtl]

Comment by labo...@gmail.com, 2012-05-07T07:38:58Z

Adding the changes in comment 2 to pydot.py solved the problem for me. On my computer the pydot.py file is in C:\Python27\Lib\site-packages\pydot-1.0.28-py2.7.egg\

[prmtl]

Comment by ero.carr...@gmail.com, 2012-06-24T11:08:19Z

With a bit of luck they will revert to not use the version in the registry key. I will add that key to the ones that are checked so pydot will find the binaries in this case as well.
Assigned to ero.carr...@gmail.com

[prmtl]

Comment by kfine...@gmail.com, 2012-07-17T04:46:20Z

I have the same problem using graphviz 2.28 on Win 7 64 bit, and the above change to pydot.py did not correct it. Any other ideas about steps to take?

Thanks

[prmtl]

Comment by jos...@gmail.com, 2012-08-09T01:11:10Z

I have run into the same issue. GraphViz 2.28 does not seem to add any keys. I have found that Method 2 seems to find the executables just fine, but this does not solve my issue. The create definition gives this error: raise InvocationException( 'Program terminated with status: %d. stderr follows: %s' % (status, stderr_output) ) Any one have any thoughts on this?

[prmtl]

Comment by shiz...@gmail.com, 2012-11-07T20:11:28Z

I run on win 7 32bit, GraphViz 2.28, same problem.

[prmtl]

Comment by shiz...@gmail.com, 2012-11-07T22:38:17Z

In win 7 32-bit:

        hkey = None
        potentialKeys = [
            "SOFTWARE\\ATT\\Graphviz",
            "SOFTWARE\\AT&T Research Labs\\Graphviz",
            "SOFTWARE\\AT&T Research Labs\\Graphviz 2.28",
        ]

[prmtl]

Comment by apmat...@gmail.com, 2013-02-23T20:01:49Z

For anyone who arrives at the same problem on Windows 7 64-bit, I have come up with another possible fix. Set the GraphViz installation path in pydot.py explicitly, ala:

for potentialKey in potentialKeys:

try:
    path = "C:\Program Files (x86)\Graphviz2.30"

    # The regitry variable might exist, left by old installations
    # but with no value, in those cases we keep searching...
    if not path:
        continue

    # Now append the "bin" subdirectory:
    #
    path = os.path.join(path, "bin")
    progs = __find_executables(path)
    if progs is not None :
        #print "Used Windows registry"
        return progs

except Exception, excp:
    #raise excp
    pass
else:
    break

• Note that this has only been tried with Windows 7 Professional 64-Bit with PyDot 1.0.28-py2.7 and GraphViz 2.30, however it did allow for successful operation of calls to GraphViz from the NetworkX package.

[prmtl]

Comment by christop...@gmail.com, 2013-04-10T05:19:25Z

Method proposed by # 10 also works on Windows 7 Professional 32-Bit with PyDot 1.0.28-py2.7 and GraphViz 2.30.

[prmtl]

Comment by abolot...@gmail.com, 2013-04-16T05:08:07Z

Same thing happening with Windows7x32 and GraphViz2.30.

There are no entries in the register at all! is there a walk-around for this, please?

[prmtl]

Comment by sidere...@gmail.com, 2013-08-22T17:57:02Z

I am running Windows 7 64 bit, and spent a long time trying to solve this issue.

What ultimately worked for me was to open pydot.py and search for the find_graphviz() function. I commented out the entirety of the function and then wrote:

return __find_executables("C:\Program Files (x86)\Graphviz2.32\bin")

The path indicates where all the executables are for Graphviz. I have no idea if this will work for everyone, but try locating that path and enter it as shown into the function and hopefully Graphviz can work for you too!

[prmtl]

Comment by boyet...@gmail.com, 2014-01-18T11:56:22Z

Here's a patch that doesn't change existing functionality, but adds a version agnostic search for the Windows GraphViz executable.
Attached windows_exec_search.patch (view on Gist)