Plugin Development

The capabilities of Girder can be extended via plugins. The plugin framework is designed to allow Girder to be as flexible as possible, on both the client and server sides.

A plugin is self-contained in a single directory. To create your plugin, simply create a directory within the plugins directory. In fact, that directory is the only thing that is truly required to make a plugin in Girder. All of the other components discussed henceforth are optional.

Example Plugin

We’ll use a contrived example to demonstrate the capabilities and components of a plugin. Our plugin will be called cats.

cd plugins ; mkdir cats

The first thing we should do is create a plugin config file in the cats directory. As promised above, this file is not required, but is strongly recommended by convention. This file contains high-level information about your plugin, and can be either JSON or YAML. If you want to use YAML features, make sure to name your config file plugin.yml instead of plugin.json. For our example, we’ll just use JSON.

touch cats/plugin.json

The plugin config file should specify a human-readable name and description for your plugin. It can also optionally contain a URL to documentation and a list of other plugins that your plugin depends on. If your plugin has dependencies, the other plugins will be enabled whenever your plugin is enabled. The contents of plugin.json for our example will be:

Note

If you have both plugin.json and plugin.yml files in the directory, the plugin.json will take precedence.

{
    "name": "My Cats Plugin",
    "description": "Allows users to manage their cats.",
    "url": "http://girder.readthedocs.io/en/latest/plugin/mycat.html",
    "version": "1.0.0",
    "dependencies": ["other_plugin"]
}

Note

Some plugins depend on other plugins, but only for building web client code, not at runtime. For these cases, rather than the dependencies field, use the staticWebDependencies field instead. This will allow the plugin to import web code from the other plugin, but will not require the other plugin to be built or enabled at runtime.

This information will appear in the web client administration console, and administrators will be able to enable and disable it there. Whenever plugins are enabled or disabled, a server restart is required in order for the change to take effect.

If you are developing a plugin for girder, sometimes using the Rebuild and restart button on the Plugins page may be undesirable as it will rebuild core and all enabled plugins in production mode, which will take some time and doesn’t provide sourcemaps. Rebuild specific plugin restart the server may be a better choice. See During Development for details.

Extending the Server-Side Application

Girder plugins can augment and alter the core functionality of the system in almost any way imaginable. These changes can be achieved via several mechanisms which are described below. First, in order to implement the functionality of your plugin, create a server directory within your plugin, and make it a Python package by creating __init__.py.

cd cats ; mkdir server ; touch server/__init__.py

This package will be imported at server startup if your plugin is enabled. Additionally, if your package implements a load function, that will be called. This load function is where the logic of extension should be performed for your plugin.

def load(info):
    ...

This load function must take a single argument, which is a dictionary of useful information passed from the core system. This dictionary contains an apiRoot value, which is the object to which you should attach API endpoints, a config value, which is the server’s configuration dictionary, and a serverRoot object, which can be used to attach endpoints that do not belong to the web API.

Within your plugin, you may import packages using relative imports or via the girder.plugins package. This will work for your own plugin, but you can also import modules from any active plugin. You can also import core Girder modules using the girder package as usual. Example:

from girder.plugins.cats import some_module
from girder import events

Adding a new route to the web API

If you want to add a new route to an existing core resource type, just call the route() function on the existing resource type. For example, to add a route for GET /item/:id/cat to the system,

from girder.api import access
from girder.api.rest import boundHandler

@access.public
@boundHandler
def myHandler(self, id, params):
    self.requireParams('cat', params)

    return {
       'itemId': id,
       'cat': params['cat']
    }

def load(info):
    info['apiRoot'].item.route('GET', (':id', 'cat'), myHandler)

You should always add an access decorator to your handler function or method to indicate who can call the new route. The decorator is one of @access.admin (only administrators can call this endpoint), @access.user (any user who is logged in can call the endpoint), or @access.public (any client can call the endpoint).

In the above example, the girder.api.rest.boundHandler decorator is used to make the unbound method myHandler behave as though it is a member method of a girder.api.rest.Resource instance, which enables convenient access to methods like self.requireParams.

If you do not add an access decorator, a warning message appears: WARNING: No access level specified for route GET item/:id/cat. The access will default to being restricted to administrators.

When you start the server, you may notice a warning message appears: WARNING: No description docs present for route GET item/:id/cat. You can add self-describing API documentation to your route using the autoDescribeRoute decorator and girder.api.describe.Description class as in the following example:

from girder.api.describe import Description, autoDescribeRoute
from girder.api import access

@access.public
@autoDescribeRoute(
    Description('Retrieve the cat for a given item.')
    .param('id', 'The item ID', paramType='path')
    .param('cat', 'The cat value.', required=False)
    .errorResponse())
def myHandler(id, cat):
    return {
       'itemId': id,
       'cat': cat
    }

That will make your route automatically appear in the Swagger documentation and will allow users to interact with it via that UI. See the RESTful API docs for more information about the Swagger page. In addition, the autoDescribeRoute decorator handles a lot of the validation and type coercion for you, with the benefit of ensuring that the documentation of the endpoint inputs matches their actual behavior. Documented parameters will be sent to the method as kwargs (so the order you declare them in the header doesn’t matter). Any additional parameters that were passed but not listed in the Description object will be contained in the params kwarg as a dictionary, if that parameter is present. The validation of required parameters, coercion to the correct data type, and setting default values is all handled automatically for you based on the parameter descriptions in the Description object passed. Two special methods of the Description object can be used for additional behavior control: girder.api.describe.Description.modelParam() and girder.api.describe.Description.jsonParam().

The modelParam method is used to convert parameters passed in as IDs to the model document corresponding to those IDs, and also can perform access checks to ensure that the user calling the endpoint has the requisite access level on the resource. For example, we can convert the above handler to use it:

@access.public
@autoDescribeRoute(
    Description('Retrieve the cat for a given item.')
    .modelParam('id', 'The item ID', model='item', level=AccessType.READ)
    .param('cat', 'The cat value.', required=False)
    .errorResponse())
def myHandler(item, cat, params):
    return {
       'item': item,
       'cat': cat
    }

The jsonParam method can be used to indicate that a parameter should be parsed as a JSON string into the corresponding python value and passed as such.

If you are creating routes that you explicitly do not wish to be exposed in the Swagger documentation for whatever reason, you can pass hide=True to the autoDescribeRoute decorator, and no warning will appear.

@autoDescribeRoute(Description(...), hide=True)

Adding a new resource type to the web API

Perhaps for our use case we determine that cat should be its own resource type rather than being referenced via the item resource. If we wish to add a new resource type entirely, it will look much like one of the core resource classes, and we can add it to the API in the load() method.

from girder.api.rest import Resource

class Cat(Resource):
    def __init__(self):
        super(Cat, self).__init__()
        self.resourceName = 'cat'

        self.route('GET', (), self.findCat)
        self.route('GET', (':id',), self.getCat)
        self.route('POST', (), self.createCat)
        self.route('PUT', (':id',), self.updateCat)
        self.route('DELETE', (':id',), self.deleteCat)

    def getCat(self, id, params):
        ...

def load(info):
    info['apiRoot'].cat = Cat()

Adding a prefix to an API

It is possible to provide a prefix to your API, allowing associated endpoints to be grouped together. This is done by creating a prefix when mounting the resource. Note that resourceName is not provided as the resource name is also derived from the mount location.

from girder.api.rest import Resource, Prefix

class Cat(Resource):
    def __init__(self):
        super(Cat, self).__init__()

        self.route('GET', (), self.findCat)
        self.route('GET', (':id',), self.getCat)
        self.route('POST', (), self.createCat)
        self.route('PUT', (':id',), self.updateCat)
        self.route('DELETE', (':id',), self.deleteCat)

    def getCat(self, id, params):
        ...

def load(info):
    info['apiRoot'].meow = Prefix()
    info['apiRoot'].meow.cat = Cat()

The endpoints are now mounted at meow/cat/

Adding a new model type in your plugin

Most of the time, if you add a new resource type in your plugin, you’ll have a Model class backing it. These model classes work just like the core model classes as described in the Models section.

Adding custom access flags

Girder core provides a way to assign a permission level (read, write, and own) to data in the hierarchy to individual users or groups. In addition to this level, users and groups can also be granted special access flags on resources in the hierarchy. If you want to expose a new access flag on data, have your plugin globally register the flag in the system:

from girder.constants import registerAccessFlag

registerAccessFlag(key='cats.feed', name='Feed cats', description='Allows users to feed cats')

When your plugin is enabled, a new checkbox will automatically appear in the access control dialog allowing resource owners to specify what users and groups are allowed to feed cats (assuming cats are represented by data in the hierarchy). Additionally, if your resource is public, you will also be able to configure which access flags are available to the public. If your plugin exposes another endpoint, say POST cat/{id}/food, inside that route handler, you can call requireAccessFlags, e.g.:

from girder.plugins.cats.models.cat import Cat

@access.user
@autoDescribeRoute(
    Description('Feed a cat')
    .modelParam('id', 'ID of the cat', model=Cat, level=AccessType.WRITE)
)
def feedCats(self, cat, params):
    Cat().requireAccessFlags(item, user=getCurrentUser(), flags='cats.feed')

    # Feed the cats ...

That will throw an AccessException if the user does not possess the specified access flag(s) on the given resource. You can equivalently use the Description.modelParam method using autoDescribeRoute, passing a requiredFlags parameter, e.g.:

@access.user
@autoDescribeRoute(
    Description('Feed a cat')
    .modelParam('id', 'ID of the cat', model='cat', plugin='cats', level=AccessType.WRITE,
                requiredFlags='cats.feed')
)
def feedCats(self, cat, params):
    # Feed the cats ...

Normally, anyone with ownership access on the resource will be allowed to enable the flag on their resources. If instead you want to make it so that only site administrators can enable your custom access flag, pass admin=True when registering the flag, e.g.

registerAccessFlag(key='cats.feed', name='Feed cats', admin=True)

We cannot prescribe exactly how access flags should be used; Girder core does not expose any on its own, and the sorts of policies that they will enforce will be entirely defined by the logic of your plugin.

The events system

In addition to being able to augment the core API as described above, the core system fires a known set of events that plugins can bind to and handle as they wish.

In the most general sense, the events framework is simply a way of binding arbitrary events with handlers. The events are identified by a unique string that can be used to bind handlers to them. For example, if the following logic is executed by your plugin at startup time,

from girder import events

def handler(event):
    print event.info

events.bind('some_event', 'my_handler', handler)

And then during runtime the following code executes:

events.trigger('some_event', info='hello')

Then hello would be printed to the console at that time. More information can be found in the API documentation for Events.

There are a specific set of known events that are fired from the core system. Plugins should bind to these events at load time. The semantics of these events are enumerated below.

  • Before REST call

Whenever a REST API route is called, just before executing its default handler, plugins will have an opportunity to execute code or conditionally override the default behavior using preventDefault and addResponse. The identifiers for these events are of the form rest.get.item/:id.before. They receive the same kwargs as the default route handler in the event’s info.

Since handlers of this event run prior to the normal access level check of the underlying route handler, they are bound by the same access level rules as route handlers; they must be decorated by one of the functions in girder.api.access. If you do not decorate them with one, they will default to requiring administrator access. This is to prevent accidental reduction of security by plugin developers. You may change the access level of the route in your handler, but you will need to do so explicitly by declaring a different decorator than the underlying route handler.

  • After REST call

Just like the before REST call event, but this is fired after the default handler has already executed and returned its value. That return value is also passed in the event.info for possible alteration by the receiving handler. The identifier for this event is, e.g., rest.get.item/:id.after.

You may alter the existing return value, for example adding an additional property

event.info['returnVal']['myProperty'] = 'myPropertyValue'

or override it completely using preventDefault and addResponse on the event

event.addResponse(myReplacementResponse)
event.preventDefault()
  • Before model save

You can receive an event each time a document of a specific resource type is saved. For example, you can bind to model.folder.save if you wish to perform logic each time a folder is saved to the database. You can use preventDefault on the passed event if you wish for the normal saving logic not to be performed.

  • After model creation

You can receive an event after a resource of a specific type is created and saved to the database. This is sent immediately before the after-save event, but only occurs upon creation of a new document. You cannot prevent any default actions with this hook. The format of the event name is, e.g. model.folder.save.created.

  • After model save

You can also receive an event after a resource of a specific type is saved to the database. This is useful if your handler needs to know the _id field of the document. You cannot prevent any default actions with this hook. The format of the event name is, e.g. model.folder.save.after.

  • Before model deletion

Triggered each time a model is about to be deleted. You can bind to this via e.g., model.folder.remove and optionally preventDefault on the event.

  • During model copy

Some models have a custom copy method (folder uses copyFolder, item uses copyItem). When a model is copied, after the initial record is created, but before associated models are copied, a copy.prepare event is sent, e.g. model.folder.copy.prepare. The event handler is passed a tuple of ((original model document), (copied model document)). If the copied model is altered, the handler should save it without triggering events.

When the copy is fully complete, and copy.after event is sent, e.g. model.folder.copy.after.

  • Override model validation

You can also override or augment the default validate methods for a core model type. Like the normal validation, you should raise a ValidationException for failure cases, and you can also preventDefault if you wish for the normal validation procedure not to be executed. The identifier for these events is, e.g., model.user.validate.

  • Override user authentication

If you want to override or augment the normal user authentication process in your plugin, bind to the auth.user.get event. If your plugin can successfully authenticate the user, it should perform the logic it needs and then preventDefault on the event and addResponse containing the authenticated user document.

  • Before file upload

This event is triggered as an upload is being initialized. The event model.upload.assetstore is sent before the model.upload.save event. The event information is a dictionary containing model and resource with the resource model type and resource document of the upload parent. For new uploads, the model type will be either item or folder. When the contents of a file are being replaced, this will be a file. To change from the current assetstore, add an assetstore key to the event information dictionary that contains an assetstore model document.

  • Just before a file upload completes

The event model.upload.finalize after the upload is completed but before the new file is saved. This can be used if the file needs to be altered or the upload should be cancelled at the last moment.

  • On file upload

This event is always triggered asynchronously and is fired after a file has been uploaded. The file document that was created is passed in the event info. You can bind to this event using the identifier data.process.

  • Before file move

The event model.upload.movefile is triggered when a file is about to be moved from one assetstore to another. The event information is a dictionary containing file and assetstore with the current file document and the target assetstore document. If preventDefault is called, the move will be cancelled.

Note

If you anticipate your plugin being used as a dependency by other plugins, and want to potentially alert them of your own events, it can be worthwhile to trigger your own events from within the plugin. If you do that, the identifiers for those events should begin with the name of your plugin, e.g., events.trigger('cats.something_happened', info='foo')

  • User login

The event model.user.authenticate is fired when a user is attempting to login via a username and password. This allows alternative authentication modes to be used instead of core, or prior to attempting core authentication. The event info contains two keys, “login” and “password”.

Extending the Client-Side Application

The web client may be extended independently of the server side. Plugins may import Pug templates, Stylus files, and JavaScript files into the application. The plugin loading system ensures that only content from enabled plugins gets loaded into the application at runtime.

By default, all of your plugin’s extensions to the web client must live in a directory in the top level of your plugin called web_client.

cd plugins/cats ; mkdir web_client

Under the web_client directory, you must have a webpack entry point file called main.js. In this file, you can import code from your plugin using relative paths, or relative to the special alias girder_plugins/<your_plugin_key>. For example, import template from 'girder_plugins/cats/templates/myTemplate.pug would import the template file located at plugins/cats/web_client/templates/myTemplate.pug. Core Girder code can be imported relative to the path girder, for example import View from 'girder/views/View';. The entry point defined in your main.js file will be automatically built once the plugin has been enabled, and your built code will be served with the application once the server has been restarted.

You can also customize which file is used as the webpack entry point, using a webpack section in your plugin config. The main property is a path relative to your plugin directory naming the entry point file (by default, as discussed above, the value of this property is web_client/main.js):

{
    "name": "MY_PLUGIN",
    "webpack": {
        "main": "web_external/index.js"
    }
}

You may also set main to an object that maps bundle names to entry points, which is helpful for plugins that want to build multiple targets using the same loaders. For example:

{
    "name": "MY_PLUGIN",
    "webpack": {
        "main": {
            "plugin": "web_client/main.js",
            "external": "web_external/main.js"
        }
    }
}

That will cause both plugin.min.* and external.min.* files to appear in the built directory. The file paths of the entry points should be specified relative to the plugin directory.

Customizing the Webpack Build

Girder’s core webpack configuration may not be quite right for your plugin. The plugin config’s webpack section may contain a configHelper property (default value: webpack.helper.js) that names a relative path to a JavaScript file that exports a “webpack helper”. This helper is simply a function of two arguments - Girder’s core webpack configuration object, and a hash of useful data about the plugin build - that returns a modified webpack configuration to use to build the plugin. This can be useful if you wish to use custom webpack loaders or plugins to build your plugin.

The object passed to the helper function contains the following keys:

  • plugin: the name of the plugin
  • output: the name of the output bundle, which is “plugin” by default.
  • main: the full path to the entry point file for the bundle.
  • pluginEntry: the webpack entry point for the plugin (e.g. plugins/MY_PLUGIN/plugin)
  • pluginDir: the full path to the plugin directory
  • nodeDir: the full path to the plugin’s dedicated NPM dependencies

Additionally, you can instruct the build system to start with an empty loader list. You may want to do this to ensure that your plugin files are processed by webpack exactly as you see fit, and not risk any of Girder’s predefined loaders getting involved where you may not expect them. To use this option, set the webpack.defaultLoaders property to false (the property is true by default):

{
    "name": "MY_PLUGIN",
    "webpack": {
        "configHelper": "plugin_webpack.js",
        "defaultLoaders": false
    }
}

Installing custom dependencies from npm

If your application requires third-party npm packages to be installed, there are a few ways to achieve this. The first is to declare them in your plugin.json file under npm.dependencies:

{
    "name": "MY_PLUGIN",
    "npm": {
        "dependencies": {
            "vega": "^2.6.0"
        }
    }
}

You can also name a JSON file containing NPM dependencies, as follows:

{
    "name": "MY_PLUGIN",
    "npm": {
        "file": "package.json",
        "fields": ["devDependencies"],
        "localNodeModules": true
    }
}

The npm.file property is a path to a JSON file relative to the plugin directory (package.json is a convenient choice, simply because the npm install --save-dev command manipulates this file by default), while npm.fields specifies which top-level keys in that file contain package names to install (by default, this property has the value ['devDependencies', 'dependencies', 'optionalDependencies']). If the localNodeModules option is set to true, then the dependencies will be installed within a separate directory so that they will not collide with Girder’s own set of node_modules.

The final alternative for Webpack-built plugins is to set the npm.install configuration property to true; this will cause the build system to run npm install in the plugin directory.

When you use the import directive within your plugin code, for example:

import foobar from 'foobar';

The build process will search for the 'foobar' module in the following locations, in order:

  1. The plugin’s local modules directory that is created if npm.localNodeModules has been set to true in the plugin configuration file.
  2. The node_modules directory underneath the plugin directory, which would exist when using npm.install: true, or if node modules had been installed there manually.
  3. Within Girder’s own node_modules directory.

Note

One notable exception to this rule is for the jQuery library; having multiple versions of jQuery from different targets often breaks things at runtime, so plugins will always use the same jQuery as Girder core.

If for some reason you need to modify this search order for your plugin, you can do so via the webpack.helper.js file documented in the Customizing the Webpack Build section. To do so, you can override the resolve.modules field of the configuration and set it to a list of paths to search in order. If you need to modify the path to search for webpack loaders instead of module imports, use the resolveLoader.modules list instead.

Controlling the Build Output

In the plugin config’s webpack section, you can set the webpack.output property to control the name of the plugin bundle file. By default this value is plugin, so that the resulting file will be clients/web/static/build/plugins/MY_PLUGIN/plugin.min.js. Girder automatically detects such files named plugin.min.js and automatically loads them into the main web client.

To create an “external” plugin, simply change the output name to any other value. One reasonable choice is index. These plugins can be used to create wholly independent web clients that don’t explicitly depend on the core Girder client being loaded.

Note

If you use an object to specify an output to entry point mapping in webpack.main, the webpack.output value will be ignored if specified.

Executing custom Grunt build steps for your plugin

For more complex plugins which require custom Grunt tasks to build, the user can specify custom targets within their own Grunt file that will be executed when the main Girder Grunt step is executed. To use this functionality, add a grunt key to your plugin.json file.

{
"name": "MY_PLUGIN",
"grunt":
    {
    "file" : "Gruntfile.js",
    "defaultTargets": [ "MY_PLUGIN_TASK" ],
    "autobuild": true
    }
}

This will allow to register a Gruntfile relative to the plugin root directory and add any target to the default one using the “defaultTargets” array.

Note

The file key within the grunt object must be a path that is relative to the root directory of your plugin. It does not have to be called Gruntfile.js, it can be called anything you want.

Note

Girder creates a number of Grunt build tasks that expect plugins to be organized according to a certain convention. To opt out of these tasks, add an autobuild key (default: true) within the grunt object and set it to false.

All paths within your custom Grunt tasks must be relative to the root directory of the Girder source repository, rather than relative to the plugin directory.

module.exports = function (grunt) {
    grunt.registerTask('MY_PLUGIN_TASK', 'Custom plugin build task', function () {
        /* ... Execute custom behavior ... */
    });
};

JavaScript extension capabilities

Plugins may bind to any of the normal events triggered by core via a global events object that can be imported like so:

import events from 'girder/events';

...

this.listenTo(events, 'g:event_name', () => { do.something(); });

This will accommodate certain events, such as before and after the application is initially loaded, and when a user logs in or out, but most of the time plugins will augment the core system using the power of JavaScript rather than the explicit events framework. One of the most common use cases for plugins is to execute some code either before or after one of the core model or view functions is executed. In an object-oriented language, this would be a simple matter of extending the core class and making a call to the parent method. The prototypal nature of JavaScript makes that pattern impossible; instead, we’ll use a slightly less straightforward but equally powerful mechanism. This is best demonstrated by example. Let’s say we want to execute some code any time the core HierarchyWidget is rendered, for instance to inject some additional elements into the view. We use Girder’s wrap utility function to wrap the method of the core prototype with our own function.

import HierarchyWidget from 'girder/views/widgets/HierarchyWidget';
import { wrap } from 'girder/utilities/PluginUtils';

// Import our template file from our plugin using a relative path
import myTemplate from './templates/hierachyWidgetExtension.pug';

// CSS files pertaining to this view should be imported as a side-effect
import './stylesheets/hierarchyWidgetExtension.styl';

wrap(HierarchyWidget, 'render', function (render) {
    // Call the underlying render function that we are wrapping
    render.call(this);

    // Add a link just below the widget using our custom template
    this.$('.g-hierarchy-widget').after(myTemplate());
});

Notice that instead of simply calling render(), we call render.call(this). That is important, as otherwise the value of this will not be set properly in the wrapped function.

Now that we have added the link to the core view, we can bind an event handler to it to make it functional:

HierarchyWidget.prototype.events['click a.cat-link'] = () => {
    alert('meow!');
};

This demonstrates one simple use case for client plugins, but using these same techniques, you should be able to do almost anything to change the core application as you need.

JavaScript events

The JavaScript client handles notifications from the server and Backbone events in client-specific code. The server notifications originate on the server and can be monitored by both the server’s Python code and the client’s JavaScript code. The client Backbone events are solely within the web client, and do not get transmitted to the server.

If the connection to the server is interrupted, the client will not receive server events. Periodically, the client will attempt to reconnect to the server to resume handling events. Similarly, if client’s browser tab is placed in the background for a long enough period of time, the connection that listens for server events will be stopped to prevent excessive resource use. When the browser’s tab regains focus, the client will once again receive server events.

When the connection to the server’s event stream is interrupted, a g:eventStream.stop Backbone event is triggered on the EventStream object. When the server is once more sending events, it first sends a g:eventStream.start event. Clients can listen to these events and refresh necessary components to ensure that data is current.

Setting an empty layout for a route

If you have a route in your plugin that you would like to have an empty layout, meaning that the Girder header, nav bar, and footer are hidden and the Girder body is evenly padded and displayed, you can specify an empty layout in the navigateTo event trigger.

As an example, say your plugin wanted a frontPage route for a Collection which would display the Collection with only the Girder body shown, you could add the following route to your plugin.

import events from 'girder/events';
import router from 'girder/router';
import { Layout } from 'girder/constants';
import CollectionModel from 'girder/models/CollectionModel';
import CollectionView from 'girder/views/body/CollectionView';

router.route('collection/:id/frontPage', 'collectionFrontPage', function (collectionId, params) {
    var collection = new CollectionModel();
    collection.set({
        _id: collectionId
    }).on('g:fetched', function () {
        events.trigger('g:navigateTo', CollectionView, _.extend({
            collection: collection
        }, params || {}), {layout: Layout.EMPTY});
    }, this).on('g:error', function () {
        router.navigate('/collections', {trigger: true});
    }, this).fetch();
});

Automated testing for plugins

Girder makes it easy to add automated testing to your plugin that integrates with the main Girder testing framework. In general, any CMake code for configuring testing can be added to the plugin.cmake file in your plugin. For example:

cd plugins/cats ; touch plugin.cmake

That file will be automatically included when Girder is configured by CMake. To add tests for your plugin, you can make use of a handy CMake function provided by the core system. Simply add to your plugin.cmake:

add_standard_plugin_tests()

This will automatically run static analysis tools on most parts of your plugin, including the server, client, and testing files. Additionally, it will detect and run any tests in the special plugin_tests directory of your plugin, provided that server-side tests are named with the suffix _test.py (and the directory contains a __init__.py to make it a Python module) and client-side tests are named with the suffix Spec.js. For example:

cd plugins/cats; mkdir plugin_tests ; cd plugin_tests ; touch __init__.py cat_test.py catSpec.js

For more sophisticated configuration of plugin testing, options to add_standard_plugin_tests can be used to disable some of the automatically-added tests, so they can be explicitly added with additional options. See the add_standard_plugin_tests implementation for full option documentation.

Testing Server-Side Code

Note

Support for pytest tests has not yet been added to plugins.

The plugin_tests/cat_test.py file should look like:

from tests import base


def setUpModule():
    base.enabledPlugins.append('cats')
    base.startServer()


def tearDownModule():
    base.stopServer()


class CatsCatTestCase(base.TestCase):

    def testCatsWork(self):
        ...

You can use all of the testing utilities provided by the base.TestCase class from core. You will also get coverage results for your plugin aggregated with the main Girder coverage results if coverage is enabled.

Note

When enabling coverage in a plugin, only files residing under the plugin’s server directory will be included. See Setting python code coverage paths to change the paths used to generate python coverage reports.

Testing Client-Side Code

Web client components may also be tested, using the Jasmine 1.3 test framework.

At the start of a plugin client test file, the built plugin files must be explicitly loaded, typically with the girderTest.importPlugin function.

Note

Plugin dependency resolution will not take place when loading built plugin files in the test environment. If your plugin has dependencies on other Girder plugins, you should make multiple calls to girderTest.importPlugin, loading any dependant plugins in topologically sorted order, before loading your plugin with girderTest.importPlugin last.

If the plugin test requires an instance of the Girder client app to be running, it can be started with girderTest.startApp() immediately after plugins are imported. Plugin tests that perform only unit tests or standalone instantiation of views may be able to skip starting the Girder client app.

Jasmine specs (defined with it) are not run until the plugin (and app, if started) are fully loaded, so they should be defined directly inside a suite (defined with describe) at the top-level.

For example, the cats plugin would define tests in a plugin_tests/catSpec.js file, like:

girderTest.importPlugin('cats');
girderTest.startApp();

describe("Test the cats plugin", function() {
    it("tests some new functionality", function() {
        ...
    });
});

Using External Data Artifacts

Plugin tests can also use the external data artifact interface provided by Girder as described in Downloading External Data Artifacts for Test Cases. The artifact key files should be placed inside a directory called plugin_tests/data/. Tests which depend on these artifacts should be explicitly added using the EXTERNAL_DATA option, with arguments of data artifact names (without the hash file extension) prefixed by plugins/<plugin_name>. For example:

add_standard_plugin_tests(NO_SERVER_TESTS)
add_python_test(cats_server_test PLUGIN cats EXTERNAL_DATA plugins/cats/test_file.txt)

Then, within your test environment, the artifact will be available under the a location specified by the GIRDER_TEST_DATA_PREFIX environment variable, in the subdirectory plugins/<plugin_name>. For example, in the same cats_server_test, the artifact file can be loaded at the path:

os.path.join(os.environ['GIRDER_TEST_DATA_PREFIX'], 'plugins', 'cats', 'test_file.txt')

Customizing Static Analysis of Client-Side Code

Girder uses ESLint to perform static analysis of its own JavaScript files. If the add_standard_plugin_tests CMake macro is used, these same tests are run on all Javascript code in the web_client and plugin_tests directories of a plugin.

However, plugin developers can also choose to extend or even entirely override the core style rules. To do this, you only need to provide a path to a custom ESLint configuration file, using the ESLINT_CONFIG_FILE option to add_eslint_test. Of course, since add_standard_plugin_tests should be prevented from adding these tests, static analysis should also be manually added to PugJS template files with add_puglint_test and add_stylint_test. For example:

add_standard_plugin_tests(NO_CLIENT)
add_eslint_test(js_static_analysis_cats "${PROJECT_SOURCE_DIR}/plugins/cats/web_client"
    ESLINT_CONFIG_FILE "${PROJECT_SOURCE_DIR}/plugins/cats/.eslintrc.json")
add_puglint_test(cats "${PROJECT_SOURCE_DIR}/plugins/cats/web_client/templates")
add_stylint_test(cats "${PROJECT_SOURCE_DIR}/plugins/cats/web_client/stylesheets")

You can configure ESLint inside your .eslintrc.json file however you choose. For example, to extend Girder’s own configuration to add a new global variable cats and stop requiring semicolons to terminate statements, you can put the following in your .eslintrc.json:

{
    "extends": "../../.eslintrc.json",
    "globals": {
        "cats": true
    },
    "rules": {
        "semi": 0
    }
}