pass allowed query parameters to spawner via user options

binderhub/app.py

@@ -21,7 +21,7 @@
 import tornado.log
 from tornado.log import app_log
 import tornado.web
-from traitlets import Unicode, Integer, Bool, Dict, validate, TraitError, default
+from traitlets import Unicode, Integer, Bool, Dict, validate, TraitError, default, Set
 from traitlets.config import Application
 from jupyterhub.services.auth import HubOAuthCallbackHandler
 
@@ -402,6 +402,16 @@ def _template_path_default(self):
         config=True,
     )
 
+    query_parameter_names = Set(
+        trait=Unicode(),
+        default_value=set(),
+        help="""
+        List of allowed names. Before launch, BinderHub checks if they exist in the query and 
+        pass found ones with their value to spawner's user_options.
+        """,
+        config=True
+    )
+
     @staticmethod
     def add_url_prefix(prefix, handlers):
         """add a url prefix to handlers"""
@@ -512,7 +522,8 @@ def initialize(self, *args, **kwargs):
             'executor': self.executor,
             'auth_enabled': self.auth_enabled,
             'use_named_servers': self.use_named_servers,
-            'event_log': self.event_log
+            'event_log': self.event_log,
+            'query_parameter_names': self.query_parameter_names
         })
         if self.auth_enabled:
             self.tornado_settings['cookie_secret'] = os.urandom(32)

binderhub/builder.py

@@ -470,6 +470,22 @@ async def launch(self, kube):
         log("Launching pod for %s: %s other pods running this repo (%s total)",
             self.repo_url, matching_pods, total_pods)
 
+        # get query parameters
+        user_options = {}
+        options_message = []
+        for name in self.settings['query_parameter_names']:
+            value = self.get_query_argument(name, None)
+            if value is not None:
+                user_options[name] = value
+                m = f"Passing option {name} with value {value} to spawner"
+                app_log.info(m)
+                options_message.append(m)
+        if options_message:
+            await self.emit({
+                'phase': 'launching',
+                'message': '\n'.join(options_message)+'\n',
+            })
+
         await self.emit({
             'phase': 'launching',
             'message': 'Launching server...\n',
@@ -494,7 +510,8 @@ async def launch(self, kube):
                 server_name = ''
             try:
                 server_info = await launcher.launch(image=self.image_name, username=username,
-                                                    server_name=server_name, repo_url=self.repo_url)
+                                                    server_name=server_name, repo_url=self.repo_url,
+                                                    user_options=user_options)
                 LAUNCH_TIME.labels(
                     status='success', retries=i,
                 ).observe(time.perf_counter() - launch_starttime)

binderhub/launcher.py

@@ -117,16 +117,14 @@ def unique_name_from_repo(self, repo_url):
         # add a random suffix to avoid collisions for users on the same image
         return '{}-{}'.format(prefix, ''.join(random.choices(SUFFIX_CHARS, k=SUFFIX_LENGTH)))
 
-    async def launch(self, image, username, server_name='', repo_url=''):
+    async def launch(self, image, username, server_name='', repo_url='', user_options=None):
         """Launch a server for a given image
 
         - creates a temporary user on the Hub if authentication is not enabled
-        - spawns a server for temporary/authenticated user
+        - spawns a server for temporary/authenticated user with user options
         - generates a token
         - returns a dict containing:
           - `url`: the URL of the server
-          - `image`: image spec
-          - `repo_url`: the url of the repo
           - `token`: the token for the server
         """
         # TODO: validate the image argument?
@@ -153,10 +151,13 @@ async def launch(self, image, username, server_name='', repo_url=''):
                 raise web.HTTPError(409, "User %s already has a running server." % username)
 
         # data to be passed into spawner's user_options during launch
-        # and also to be returned into 'ready' state
-        data = {'image': image,
-                'repo_url': repo_url,
-                'token': base64.urlsafe_b64encode(uuid.uuid4().bytes).decode('ascii').rstrip('=\n')}
+        _user_options = {'image': image,
+                         'repo_url': repo_url,
+                         'token': base64.urlsafe_b64encode(uuid.uuid4().bytes).decode('ascii').rstrip('=\n')}
+        if user_options is None:
+            user_options = _user_options
+        else:
+            user_options.update(_user_options)
 
         # server name to be used in logs
         _server_name = " {}".format(server_name) if server_name else ''
@@ -167,7 +168,7 @@ async def launch(self, image, username, server_name='', repo_url=''):
             resp = await self.api_request(
                 'users/{}/servers/{}'.format(username, server_name),
                 method='POST',
-                body=json.dumps(data).encode('utf8'),
+                body=json.dumps(user_options).encode('utf8'),
             )
             if resp.code == 202:
                 # Server hasn't actually started yet
@@ -196,5 +197,7 @@ async def launch(self, image, username, server_name='', repo_url=''):
                           format(_server_name, username, e, body))
             raise web.HTTPError(500, "Failed to launch image %s" % image)
 
-        data['url'] = self.hub_url + 'user/%s/%s' % (username, server_name)
+        # data to be returned into 'ready' state
+        data = {'url': self.hub_url + 'user/%s/%s' % (username, server_name),
+                'token': user_options['token']}
         return data

binderhub/static/js/index.js

@@ -76,6 +76,7 @@ function updateRepoText() {
 
 function getBuildFormValues() {
   var providerPrefix = $('#provider_prefix').val().trim();
+  var userOptions = $('#user_options').val().trim();
   var repo = $('#repository').val().trim();
   if (providerPrefix !== 'git') {
     repo = repo.replace(/^(https?:\/\/)?github.com\//, '');
@@ -92,7 +93,8 @@ function getBuildFormValues() {
   var ref = $('#ref').val().trim() || 'master';
   var path = $('#filepath').val().trim();
   return {'providerPrefix': providerPrefix, 'repo': repo,
-          'ref': ref, 'path': path, 'pathType': getPathType()}
+          'ref': ref, 'path': path, 'pathType': getPathType(),
+          'userOptions': userOptions}
 }
 
 function updateUrls(formValues) {
@@ -121,7 +123,7 @@ function updateUrls(formValues) {
   }
 }
 
-function build(providerSpec, log, path, pathType) {
+function build(providerSpec, log, path, pathType, userOptions) {
   update_favicon(BASE_URL + "favicon_building.ico");
   // split provider prefix off of providerSpec
   var spec = providerSpec.slice(providerSpec.indexOf('/') + 1);
@@ -139,7 +141,7 @@ function build(providerSpec, log, path, pathType) {
 
   $('.on-build').removeClass('hidden');
 
-  var image = new BinderImage(providerSpec);
+  var image = new BinderImage();
 
   image.onStateChange('*', function(oldState, newState, data) {
     if (data.message !== undefined) {
@@ -195,7 +197,8 @@ function build(providerSpec, log, path, pathType) {
     image.launch(data.url, data.token, path, pathType);
   });
 
-  image.fetch();
+  var apiUrl = BASE_URL + "build/" + providerSpec + userOptions;
+  image.fetch(apiUrl);
   return image;
 }
 
@@ -288,7 +291,8 @@ function indexMain() {
           formValues.providerPrefix + '/' + formValues.repo + '/' + formValues.ref,
           log,
           formValues.path,
-          formValues.pathType
+          formValues.pathType,
+          formValues.userOptions
         );
         return false;
     });
@@ -310,7 +314,8 @@ function loadingMain(providerSpec) {
       pathType = 'file';
     }
   }
-  build(providerSpec, log, path, pathType);
+  var userOptions = window.location.search;
+  build(providerSpec, log, path, pathType, userOptions);
   return false;
 }
 

binderhub/static/js/src/image.js

@@ -1,13 +1,9 @@
-var BASE_URL = $("#base-url").data().url;
-
-export default function BinderImage(providerSpec) {
-  this.providerSpec = providerSpec;
+export default function BinderImage() {
   this.callbacks = {};
   this.state = null;
 }
 
-BinderImage.prototype.fetch = function() {
-  var apiUrl = BASE_URL + "build/" + this.providerSpec;
+BinderImage.prototype.fetch = function(apiUrl) {
   this.eventSource = new EventSource(apiUrl);
   var that = this;
   this.eventSource.onerror = function(err) {

binderhub/templates/index.html

@@ -24,6 +24,7 @@ <h3>Turn a Git repo into a collection of interactive notebooks</h3>
       <form id="build-form" class="form jumbotron">
         <h4 id="form-header" class='row'>Build and launch a repository</h4>
         <input type="hidden" id="provider_prefix" value="gh"/>
+        <input type="hidden" id="user_options" value=""/>
         <div class="form-group row">
           <label for="repository">GitHub repo or Gist name or GitLab.com URL</label>
           <div class="input-group">