contrib/win32/hgwebdir_wsgi.py

setup: make the error "Unable to find a working hg binary" more informative

The error message now shows the attempted hg commands and their stderr, to
make it easier to investigate why things are not working.

Here's an example output

/!\
/!\ Unable to find a working hg binary
/!\ Version cannot be extracted from the repository
/!\ Re-run the setup once a first version is built
/!\ Attempts:
/!\   attempt #0:
/!\     cmd:         ['hg-missing', 'log', '-r.', '-Ttest']
/!\     exception:   [Errno 2] No such file or directory: 'hg-missing': 'hg-missing'
/!\   attempt #1:
/!\     cmd:         ['/usr/bin/python3', 'hg', 'log', '-r.', '-Ttest']
/!\     return code: 255
/!\     std output:
/!\     std error:
*** failed to import extension "topic": No module named 'topic'
*** failed to import extension "evolve": No module named 'evolve'
abort: accessing `dirstate-v2` repository without associated fast implementation.
(check `hg help config.format.use-dirstate-v2` for details)
/!\
/!\ Could not determine the Mercurial version
/!\ You need to build a local version first
/!\ Run `make local` and try again
/!\

# An example WSGI script for IIS/isapi-wsgi to export multiple hgweb repos
# Copyright 2010-2016 Sune Foldager <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# Requirements:
# - Python 2.7, preferably 64 bit
# - Mercurial installed from source (python setup.py install) or download the
#   python module installer from https://www.mercurial-scm.org/wiki/Download
# - IIS 7 or newer
#
#
# Installation and use:
#
# - Download or clone the isapi-wsgi source and run python setup.py install.
#   https://github.com/hexdump42/isapi-wsgi
#
# - Create a directory to hold the shim dll, config files etc. This can reside
#   inside the standard IIS directory, C:\inetpub, or anywhere else. Copy this
#   script there.
#
# - Run this script (i.e. python hgwebdir_wsgi.py) to get a shim dll. The
#   shim is identical for all scripts, so you can just copy and rename one
#   from an earlier run, if you wish. The shim needs to reside in the same
#   directory as this script.
#
# - Start IIS manager and create a new app pool:
#   .NET CLR Version: No Managed Code
#   Advanced Settings: Enable 32 Bit Applications, if using 32 bit Python.
#   You can adjust the identity and maximum worker processes if you wish. This
#   setup works fine with multiple worker processes.
#
# - Create an IIS application where your hgwebdir is to be served from.
#   Assign it the app pool you just created and point its physical path to the
#   directory you created.
#
# - In the application, remove all handler mappings and setup a wildcard script
#   handler mapping of type IsapiModule with the shim dll as its executable.
#   This file MUST reside in the same directory as the shim. The easiest way
#   to do all this is to close IIS manager, place a web.config file in your
#   directory and start IIS manager again. The file should contain:
#
#   <?xml version="1.0" encoding="UTF-8"?>
#   <configuration>
#       <system.webServer>
#           <handlers accessPolicy="Read, Script">
#               <clear />
#               <add name="hgwebdir" path="*" verb="*" modules="IsapiModule"
#                    scriptProcessor="C:\your\directory\_hgwebdir_wsgi.dll"
#                    resourceType="Unspecified" requireAccess="None"
#                    preCondition="bitness64" />
#           </handlers>
#       </system.webServer>
#   </configuration>
#
#   Where "bitness64" should be replaced with "bitness32" for 32 bit Python.
#
# - Edit ISAPI And CGI Restrictions on the web server (global setting). Add a
#   restriction pointing to your shim dll and allow it to run.
#
# - Create a configuration file in your directory and adjust the configuration
#   variables below to match your needs. Example configuration:
#
#   [web]
#   style = gitweb
#   push_ssl = false
#   allow_push = *
#   encoding = utf8
#
#   [server]
#   validate = true
#
#   [paths]
#   repo1 = c:\your\directory\repo1
#   repo2 = c:\your\directory\repo2
#
# - Restart the web server and see if things are running.
#


# Configuration file location
hgweb_config = r'c:\your\directory\wsgi.config'

# Global settings for IIS path translation
path_strip = 0  # Strip this many path elements off (when using url rewrite)
path_prefix = 1  # This many path elements are prefixes (depends on the
# virtual path of the IIS application).

import sys

# Adjust python path if this is not a system-wide install
# sys.path.insert(0, r'C:\your\custom\hg\build\lib.win32-2.7')

# Enable tracing. Run 'python -m win32traceutil' to debug
if getattr(sys, 'isapidllhandle', None) is not None:
    import win32traceutil

    win32traceutil.SetupForPrint  # silence unused import warning

import isapi_wsgi
from mercurial.hgweb.hgwebdir_mod import hgwebdir

# Example tweak: Replace isapi_wsgi's handler to provide better error message
# Other stuff could also be done here, like logging errors etc.
class WsgiHandler(isapi_wsgi.IsapiWsgiHandler):
    error_status = '500 Internal Server Error'  # less silly error message


isapi_wsgi.IsapiWsgiHandler = WsgiHandler

# Only create the hgwebdir instance once
application = hgwebdir(hgweb_config)


def handler(environ, start_response):

    # Translate IIS's weird URLs
    url = environ['SCRIPT_NAME'] + environ['PATH_INFO']
    paths = url[1:].split('/')[path_strip:]
    script_name = '/' + '/'.join(paths[:path_prefix])
    path_info = '/'.join(paths[path_prefix:])
    if path_info:
        path_info = '/' + path_info
    environ['SCRIPT_NAME'] = script_name
    environ['PATH_INFO'] = path_info

    return application(environ, start_response)


def __ExtensionFactory__():
    return isapi_wsgi.ISAPISimpleHandler(handler)


if __name__ == '__main__':
    from isapi.install import ISAPIParameters, HandleCommandLine

    params = ISAPIParameters()
    HandleCommandLine(params)