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Overview
A studio can set up a central help server to serve help to multiple users of Houdini, instead of each instance of Houdini starting up its own help server on each machine. This is useful for sharing site-specific documentation between users.
This document outlines several solutions for running a central server:
-
Small scale: running the default help server. This simply runs the default Python server included with Houdini. This may be sufficient for a few simultaneous users, but for more than few users you probably want to use one of the faster solutions below.
This solution is easiest to set up and run, but only works for a small number of simultaneous users. This requires a Houdini license (such as an Apprentice license).
-
Faster: use a proxy server. This uses a standalone HTTP server such as
nginx
to serve most files, while forwarding requests for help page contents to the default Python server.This is the most balanced solution. It provides dynamic content, search, and reading help embedding in nodes, while being much faster than the default Python server alone. For a large number of users, it may not be fast enough. This requires a Houdini license (such as an Apprentice license).
-
Even faster: serve the app using a WSGI application server. This uses a WSGI application server to serve static files and handle dynamic page requests.
This provides dynamic content and search, but cannot read help embedded in nodes. It is faster and scales better than the proxy solution. This does not require a Houdini license.
-
Fastest: serving static help. This pre-generates HTML files from the wiki files in the help, so you can serve them using a plain HTTP server.
This is the fastest possible solution, and easy to set up, since it’s just serving plain static files. This solution allows you to publish Houdini’s help from an existing web server. This does not provide dynamic content, search, or help embedded in nodes. This does not require a Houdini license.
Note
This document outlines general solutions and configurations. Some of the solutions require installation and configuration of third party software. This document contains some examples, but unfortunately it can’t hope to cover all the possible combinations of platform, software, and configuration options. You may need to do your own research on the software you use, its configuration options, and how your chosen software uses standards such as WSGI.
Licensing
The help server normally requires a Houdini license to run, since it uses HOM to read help embedded in nodes and tools.
You can run hython
with any Houdini license, including an Apprentice license. The easiest thing to do is set up a central server machine and install just an Apprentice license on it, so the server process will use that.
You can ensure hython
uses an Apprentice license by disallowing the other license types:
hython --skip-license-modes="commercial,indie,education" ...
Note that serving static help does not require ongoing use of a license, but has some drawbacks. See serving static help below for more information.
Small scale: running the default help server
The easiest way to set up a central help server is simply to run the default Python help server included with Houdini. The drawback is that the Python server can only uses a single process, and serves all files (images, stylesheets, and so on) using Python code. This may be fast enough for a few people, but for more than a few users you probably need to investigate the faster options below.
-
Easy to set up.
-
Doesn’t scale well to many simultaneous users.
Command line
-
Open a Houdini shell.
Windows
Click Start ▸ All programs ▸ Side Effects Software ▸ Houdini X.X.XXX ▸ Utilities ▸ Command line tools.
Mac
In the Finder, open Applications ▸ Houdini ▸ HoudiniX.X.X ▸ Utilities ▸ Houdini Terminal.
Linux
In a
bash
shell,cd
to the Houdini install directory andsource houdini_setup
. -
In the Houdini shell, type:
hhelp serve --bgindex=true
…to start the help server with background indexing.
-
Open a browser and go to
http://localhost:8080/
hhelp serve
--host=0.0.0.0
The IP address for the server.
-
If your computer has multiple network controllers, you can specify which address you want the server to listen at.
-
Use
0.0.0.0
(the default) to make the server available to other computers. -
Use
localhost
or127.0.0.1
to make the server only available on your computer.
--port=8080
The port number for the server. Default is 8080
.
--debug
Run the server with debugging information on.
--bgindex
Re-index changed documents in the background while the server is running.
--config=path
(Optional) a file to read configuration options from.
--logfile=path
(Optional) a file to write server log to.
--loglevel=DEBUG|INFO|WARNING|ERROR
(Optional) log messages at or above this level of severity.
hhelp index
This command lets you manually update the search index (if you're not running a server with the --bgindex
option). By default the command will only update changed files, unless you pass the --clean
option.
--clean
Re-index all documents from scratch, whether they've changed or not.
--usages
Generate information about what nodes are used by example files.
--config=path
(Optional) a file to read configuration options from.
--logfile=path
(Optional) a file to write server log to.
--loglevel=DEBUG|INFO|WARNING|ERROR
(Optional) log messages at or above this level of severity.
Starting the server from hython
If you want to start the built-in server in code:
from houdinihelp.server import start_server start_server( host="0.0.0.0", # Network interface to listen to port=8080, # Port to listen to debug=False, # Whether to start the server in debug mode bgindex=None , # Whether to do background indexing config_file=None, # String path to a config file use_houdini_path=True, # See below )
-
If
config_file
isNone
anduse_houdini_path
isTrue
, the code will usehou
to search the Houdini path for aconfig/Help/bookish.cfg
configuration file (see configuration below). This will use a batch license ifhou
hasn’t already been imported. If you're specifying a configuration file in the arguments you don’t need worry about this. -
The
bgindex
keyword argument can beTrue
,False
, orNone
.None
means use the value from the configuration, whereas passingTrue
orFalse
will override the configuration.
Faster: use a proxy server
You can install and run a small web server application such as nginx
or uwsgi
and use it to serve the help’s static files directly, and “forward” (proxy) requests for help pages to the help server.
-
Relatively easy to set up.
-
Much faster than plain help server, because the standalone server takes care of most files (images, stylesheets, and so on).
-
Can still serve dynamic wiki help out of Houdini path, embedded in nodes, tools, and so on.
-
Throughput is limited because requests for page contents still go through the help server.
Set up central server directories
To set up a proxy server, do the following:
-
Start the help server process using
hhelp serve
, as shown above. -
Create a directory for your central server, and inside that, a directory for the static files:
% mkdir central central/files % cd central
-
Copy the static help files (such as images and stylesheets) into the
central/files
directory.(Some of the files we want to serve directly are shipped inside
.zip
files, so the easiest thing is to copy all the files we want into one place.)% mkdir files/icons files/images files/static % unzip $HFS/houdini/help/icons.zip -d files/icons % unzip $HFS/houdini/help/images.zip -d files/images % cp -r $HFS/houdini/help/videos videos % cp -r $HFS/houdini/python2.7libs/bookish/static/* static % cp -r $HFS/houdini/python2.7libs/houdinihelp/static/* static
(Note that we merge the contents of the
bookish/static
andhoudinihelp/static
directories from$HFS
into a singlefiles/static
directory undercentral
.) -
Create an environment variable to the absolute path your
central
directory.For example:
export CENTRAL=/home/username/central
(This is not strictly necessary, but as a convenience will use
$CENTRAL
in the examples below in place of thecentral
directory’s path.)
Set up a proxy server
-
Install a standalone HTTP server.
This step is specific to the HTTP server you want to use. We recommend a lightweight server such as
nginx
.How to install server software on your system is beyond the scope of this document. See the instructions for your chosen server for how to install it on different platforms. In general, on Linux, you can install
nginx
using your distribution’s package manager. On Mac, you can install it by first installing Homebrew and then using Homebrew to installnginx
. -
Set up your HTTP server to serve the static files directly, and proxy other requests to the help server.
This is highly specific to the HTTP server you use and how you want to configure your server. See the example below.
nginx example
Here is an example configuration file for nginx
. You can save this file in the central
directory.
proxy.nginx
configuration file
worker_processes 4; daemon off; error_log stderr; http { include /usr/local/etc/nginx/mime.types; server { listen 0.0.0.0:9090; location ~ ^/(images|icons|videos|static)/ { root $CENTRAL/files; } location / { proxy_pass http://localhost:8080/; } } } events { worker_connections 1024; }
(See the documentation for nginx
for a full list of available configuration.)
-
This example sets
daemon off
so the server does not immediate fork a separate process and return, so you can see its error messages and other output. Once you have the server set up how you want, you may decide to change this toon
so the server runs in the background. You can then instruct it to reload the config file usingnginx -s reload
, or stop usingnginx -s stop
. -
The line
include /usr/local/etc/nginx/mime.types;
may be specific to your installation. You should to check where nginx’smime.types
file was installed on your system and specify that path. -
The line
listen 0.0.0.0:9090
sets the IP address/port thenginx
server will listen on. This must be a different port from the port the help server is listening on (8080
in the examples above).Listening on
0.0.0.0
(as opposed tolocalhost
or127.0.0.1
) means that other computers on the network can access this server. -
The line
root $CENTRAL/files;
should list the absolute path to thecentral
directory you created above. You cannot use a tilde (~
) to represent your home directory in this path. -
The line
proxy_pass http://localhost:8080/;
should specify the root URL of the help server.
You can run nginx
with this configuration:
% nginx -c $CENTRAL/proxy.nginx
Note that you must specify an absolute path to the configuration file. Otherwise nginx
looks for it relative to its install directory, not the current directory. Again, you cannot use a tilde (~
) to represent your home directory in this path.
Now you can try the server by pointing a browser to:
http://localhost:9090/
Even faster: serve the app using a WSGI application server
The proxy server example above is relatively easy to set up because you can use hhelp
to start Houdini’s help server as usual, then forward requests to the help server as needed.
However, the drawback is that communicating with the help server over HTTP is somewhat inefficient, and the Python help server is still single-process/single-threaded, limiting overall throughput.
Instead of running the help server and forwarding requests to it, this solution uses a WSGI application server such as uwsgi
, gunicorn
, or Apache with modwsgi
, to run the Houdini help’s application code itself, so it can use multiprocessing and multithreading.
WSGI is a protocol that allows standalone HTTP servers to run a Python function to generate dynamic web content. The drawback is that the server usually wants to start the Python interpreter itself, so we can’t rely on hython
setting up the path to Houdini’s libraries automatically. The application.py
script listed in this section manipulates the Python path so the Houdini help app can run in plain Python.
-
Faster than the plain help server or proxy server solutions.
-
Can serve dynamic wiki help from directories you specify.
-
Doesn’t require any Houdini license.
-
Slightly harder to set up, since we can’t use
hython
(which sets up the Python path automatically to use Houdini’s libraries). -
Can’t use
hou
, so this solution can’t serve help embedded inside assets or tools.
Note
You should still run the server in a Houdini shell environment, so it has environment variables such as $HFS
available.
Setting up an application server
-
First, set up the directory structure as in setting up central server directories above.
This should give you a directory structure like this:
central/ files/ icons/ ... images/ ... videos/ ... static/ ...
-
The app server will require a script to create an
application()
function it will call to serve pages.The application server will run the script using Python, not
hython
, so it won’t automatically have the Houdini libraries available.The following example script manipulates the Python path so it can find Houdini’s libraries, and configures the application to find files under
$HFS
, before creating the application function.Save this to a file under
central
calledapplication.py
.Example
central/application.py
scriptimport logging import sys from os.path import expandvars # Add Houdini libraries to Python path sys.path.append(expandvars("$HFS/houdini/python2.7libs")) # Add Houdini's third-party Python libraries. Unfortunately this path is # platform-specific if sys.platform in ("linux", "linux2"): sys.path.append(expandvars("$HFS/python/lib/python2.7/site-packages-forced")) elif sys.platform == "darwin": sys.path.append( expandvars( "$HFS/Frameworks/Python.framework/Versions/Current/lib/python2.7/site-packages-forced" ) ) elif sys.platform in ("win32", "win64"): sys.path.append(expandvars("$HFS/python27/lib/site-packages-forced")) from houdinihelp.hconfig import HoudiniHfsConfig from houdinihelp.server import get_houdini_app class MyConfig(HoudiniHfsConfig): # The directories you want to serve from DOCUMENTS = [ # "Loose" (unzipped) files under $HFS/houdini/help expandvars("$HFS/houdini/help"), { # This adds ability to read docs out of .zip files in # $HFS/houdini/help "type": "object", "classname": "bookish.stores.ZipTree", "args": { "dirpath": expandvars("$HFS/houdini/help"), } }, # This adds files under the help dir in your user prefs expandvars("$HOUDINI_USER_PREF_DIR/help"), # Add any other directories you want to add to the server here # "/my/dir", ] # Store the cache in the user's prefs dir CACHE_DIR = expandvars("$HOUDINI_USER_PREF_DIR/config/Help/cache") # The full-text index shipped with Houdini. If you want to use background # indexing, copy this directory somewhere writable, and set this to the path # of the writable directory. INDEX_DIR = expandvars("$HFS/houdini/config/Help/index") # True if the server should run an indexing thread in the background ENABLE_BACKGROUND_INDEXING = False # Number of seconds between background indexing runs BACKGROUND_INDEXING_INTERVAL = 60 # Specify a page manager that doesn't use hou PAGES_CLASS = "houdinihelp.hpages.HoudiniPagesWithoutHou" application = get_houdini_app( use_houdini_path=False, config_obj=MyConfig, loglevel=logging.INFO, debug=False, )
-
Install a WSGI application server.
This step is specific to the server you want to use. We recommend a lightweight server such as
uwsgi
.How to install server software on your system is beyond the scope of this document. See the instructions for your chosen server for how to install it on different platforms. For
uwsgi
, you can install it using Python’spip3
package manager (pip3 install uwsgi
). This is the best installation method foruwsgi
since it installs all necessary plugins as well as the base program. -
Set up your HTTP server to serve the static files directly, and use the
application.py
script to serve dynamic help pages.This is highly specific to the app server you use and how you want to configure the server. See the documentation for your application server for details of how it works with a WSGI function, and how you specify static directories.
uwsgi example
The following command runs uwsgi
as an HTTP server, sets the listening address/port, specifies the directory to serve static files from (as set up above), and points to the script that creates the application’s WSGI function:
% uwsgi --http 0.0.0.0:9090 --check-static $CENTRAL/files $CENTRAL/application.py
Fastest: serving static help
-
Fastest, most robust solution
-
Can use any HTTP server, don’t need to configure application
-
Doesn’t require any Houdini license.
-
Only serves static pages, not dynamic wiki pages (that is, you can’t edit a wiki help file and reload to see the results immediately in the browser).
-
No search!
Pre-generate all help files
-
First, set up the directory structure as in setting up central server directories above.
This should give you a directory structure like this:
central/ files/ icons/ ... images/ ... videos/ ... static/ ...
-
In Houdini shell,
cd
to thecentral
directory. -
Run the following command:
hhelp generate files
This will generate a static HTML file from every wiki file in the Houdin help. This can take a long time.
-
Once you have generated the HTML files, you can point any HTTP server to serve the files in
central/files
.
Configuring the help server
-
You can specify a configuration file in the
hhelp
command line utility using the--config
option, or in code using theconfig_file
parameter ofhoudinihelp.server.get_houdini_app
orhoudinihelp.server.start_server
. -
If you don’t specify a configuration file and
HOUDINIPATH/config/Help/bookish.cfg
exists, the server will load it (unless you passuse_houdini_path=False
). -
The help server is based on Flask. Flask’s configuration files are actually Python.
For example, to add a directory of files at $HOME/myfiles
, put the following in the configuration file:
EXTRA_DOCUMENTS = ["$HOME/myfiles/"]
See below for some useful configuration keys.
Useful configuration keys
DOCUMENTS = [...]
The default list of document sources includes help
directories from the Houdini path, as well as special sources that allow reading help from inside assets and shelf tools. You can replace this with a list of directory paths to serve only your directories. For example:
DOCUMENTS = ["/my/dir"]
It’s possible to extend this list in your configuration file instead of replacing it, but in that case it’s easier to use EXTRA_DOCUMENTS
(see below).
EXTRA_DOCUMENTS = []
A list of “extra” document sources to be added on to the defaults in DOCUMENTS
. This is useful when you want the defaults but also want to serve from some additional directories
(Note that the default list includes the HOUDINIPATH/help
, so you can extend the Houdini path to achieve the same thing.)
EXTRA_DOCUMENTS = ["/my/dir"]
ENABLE_BACKGROUND_INDEXING = False
Whether to run a thread to re-index changed content in the background. Overridden by the --bgindex
option on the command line.
BACKGROUND_INDEXING_INTERVAL = 60
The number of seconds between re-indexes when background indexing is on.
EXTRA_SHORTCUTS = []
See search shortcuts.
CACHE_DIR = "$HOUDINI_USER_PREF_DIR/config/Help"
Where the server caches .json
files generated from wiki source files.
INDEX_DIR = "$HFS/houdini/config/Help/index"
Directory containing the search index.