data: plumb experiment ID through runs and scalars (#2580)

Summary:
This implements a rudimentary experiment selection mechanism for the
runs selector and scalars dashboard only, for the purposes of testing
data provider implementations. The experiment ID is stored as a query
parameter, which isn’t perfect because it precludes caching the big
TensorBoard HTML blob across experiments. In the long term, we can
consider refactoring to serve the big HTML blob from a static path
that’s fetched by the page.

The TensorBoard codebase still has some fragments of a previous
experimental data selector, which was partially removed in #2290, and so
parts of this diff look like changes but are functionally additions.

Test Plan:
Instrument the multiplexer data provider to log experiment IDs:

```diff
diff --git a/tensorboard/backend/event_processing/data_provider.py b/tensorboard/backend/event_processing/data_provider.py
index ef60232..4c72d096 100644
--- a/tensorboard/backend/event_processing/data_provider.py
+++ b/tensorboard/backend/event_processing/data_provider.py
@@ -54,7 +54,7 @@ class MultiplexerDataProvider(provider.DataProvider):
       return None

   def list_runs(self, experiment_id):
-    del experiment_id  # ignored for now
+    logger.warn("Listing runs for experiment %r", experiment_id)
     return [
         provider.Run(
             run_id=run,  # use names as IDs
@@ -65,7 +65,7 @@ class MultiplexerDataProvider(provider.DataProvider):
     ]

   def list_scalars(self, experiment_id, plugin_name, run_tag_filter=None):
-    del experiment_id  # ignored for now
+    logger.warn("Listing scalars for experiment %r", experiment_id)
     run_tag_content = self._multiplexer.PluginRunToTagToContent(plugin_name)
     result = {}
     if run_tag_filter is None:
@@ -96,6 +96,7 @@ class MultiplexerDataProvider(provider.DataProvider):
   def read_scalars(
       self, experiment_id, plugin_name, downsample=None, run_tag_filter=None
   ):
+    logger.warn("Reading scalars for experiment %r", experiment_id)
     # TODO(@wchargin): Downsampling not implemented, as the multiplexer
     # is already downsampled. We could downsample on top of the existing
     # sampling, which would be nice for testing.
```

Then launch TensorBoard with `--generic_data=true` and navigate to
<http://localhost:6006/?experiment=foo>; verify that all three varieties
of server logs are exclusively for the correct experiment ID.

Then, remove the query parameter, and ensure that TensorBoard still
works normally (with experiment ID the empty string).

wchargin-branch: data-experiment

Author: wchargin

tensorboard/components/tf_backend/router.ts

@@ -22,7 +22,7 @@ namespace tf_backend {
       params?: URLSearchParams
     ) => string;
     pluginsListing: () => string;
-    runs: () => string;
+    runs: (experiment?: string) => string;
     runsForExperiment: (id: tf_backend.ExperimentId) => string;
   }
 
@@ -53,7 +53,11 @@ namespace tf_backend {
         );
       },
       pluginsListing: () => createDataPath(dataDir, '/plugins_listing'),
-      runs: () => createDataPath(dataDir, '/runs'),
+      runs: (experiment?: string) => {
+        const searchParams = new URLSearchParams();
+        searchParams.set('experiment', experiment || '');
+        return createDataPath(dataDir, '/runs', searchParams);
+      },
       runsForExperiment: (id) => {
         return createDataPath(
           dataDir,
@@ -71,6 +75,13 @@ namespace tf_backend {
     return _router;
   }
 
+  /**
+   * @return {string} the experiment ID for the currently loaded page
+   */
+  export function getExperimentId() {
+    return new URLSearchParams(window.location.search).get('experiment') || '';
+  }
+
   /**
    * Set the global router, to be returned by future calls to `getRouter`.
    * You may wish to invoke this if you are running a demo server with a

tensorboard/components/tf_backend/runsStore.ts

@@ -17,7 +17,7 @@ namespace tf_backend {
     private _runs: string[] = [];
 
     load() {
-      const url = getRouter().runs();
+      const url = tf_backend.getRouter().runs(tf_backend.getExperimentId());
       return this.requestManager.request(url).then((newRuns) => {
         if (!_.isEqual(this._runs, newRuns)) {
           this._runs = newRuns;

tensorboard/components/tf_backend/test/backendTests.ts

@@ -82,18 +82,18 @@ namespace tf_backend {
 
         it('leading slash in pathPrefix is an absolute path', () => {
           const router = createRouter('/data/');
-          assert.equal(router.runs(), '/data/runs');
+          assert.equal(router.runs(), '/data/runs?experiment=');
         });
 
         it('returns complete pathname when pathPrefix omits slash', () => {
           const router = createRouter('data/');
-          assert.equal(router.runs(), 'data/runs');
+          assert.equal(router.runs(), 'data/runs?experiment=');
         });
 
         it('does not prune many leading slashes that forms full url', () => {
           const router = createRouter('///data/hello');
-          // This becomes 'http://data/hello/runs'
-          assert.equal(router.runs(), '///data/hello/runs');
+          // This becomes 'http://data/hello/runs?experiment='
+          assert.equal(router.runs(), '///data/hello/runs?experiment=');
         });
 
         it('returns correct value for #environment', () => {
@@ -177,7 +177,7 @@ namespace tf_backend {
         });
 
         it('returns correct value for #runs', () => {
-          assert.equal(router.runs(), 'data/runs');
+          assert.equal(router.runs(), 'data/runs?experiment=');
         });
 
         it('returns correct value for #runsForExperiment', () => {

tensorboard/plugins/core/core_plugin.py

@@ -154,9 +154,9 @@ def _serve_runs(self, request):
     last, and then ties are broken by sorting on the run name.
     """
     if self._data_provider:
+      experiment = request.args.get('experiment', '')
       runs = sorted(
-          # (`experiment_id=None` as experiment support is not yet implemented)
-          self._data_provider.list_runs(experiment_id=None),
+          self._data_provider.list_runs(experiment_id=experiment),
           key=lambda run: (
               run.start_time if run.start_time is not None else float('inf'),
               run.run_name,

tensorboard/plugins/scalar/scalars_plugin.py

@@ -93,11 +93,11 @@ def frontend_metadata(self):
         element_name='tf-scalar-dashboard',
     )
 
-  def index_impl(self):
+  def index_impl(self, experiment=None):
     """Return {runName: {tagName: {displayName: ..., description: ...}}}."""
     if self._data_provider:
       mapping = self._data_provider.list_scalars(
-          experiment_id=None,  # experiment support not yet implemented
+          experiment_id=experiment,
           plugin_name=metadata.PLUGIN_NAME,
       )
       result = {run: {} for run in mapping}
@@ -155,7 +155,7 @@ def scalars_impl(self, tag, run, experiment, output_format):
       # logic.
       SAMPLE_COUNT = 1000
       all_scalars = self._data_provider.read_scalars(
-          experiment_id=None,  # experiment support not yet implemented
+          experiment_id=experiment,
           plugin_name=metadata.PLUGIN_NAME,
           downsample=SAMPLE_COUNT,
           run_tag_filter=provider.RunTagFilter(runs=[run], tags=[tag]),
@@ -224,7 +224,8 @@ def _get_value(self, scalar_data_blob, dtype_enum):
 
   @wrappers.Request.application
   def tags_route(self, request):
-    index = self.index_impl()
+    experiment = request.args.get('experiment', '')
+    index = self.index_impl(experiment=experiment)
     return http_util.Respond(request, index, 'application/json')
 
   @wrappers.Request.application
@@ -233,7 +234,7 @@ def scalars_route(self, request):
     # TODO: return HTTP status code for malformed requests
     tag = request.args.get('tag')
     run = request.args.get('run')
-    experiment = request.args.get('experiment')
+    experiment = request.args.get('experiment', '')
     output_format = request.args.get('format')
     (body, mime_type) = self.scalars_impl(tag, run, experiment, output_format)
     return http_util.Respond(request, body, mime_type)

tensorboard/plugins/scalar/tf_scalar_dashboard/tf-scalar-card.html

@@ -241,7 +241,7 @@
                 new URLSearchParams({
                   tag,
                   run,
-                  experiment: experiment ? experiment.id : '',
+                  experiment: experiment || '',
                 })
               );
             };

tensorboard/plugins/scalar/tf_scalar_dashboard/tf-scalar-dashboard.html

@@ -309,7 +309,13 @@ <h3>No scalar data was found.</h3>
         });
       },
       _fetchTags() {
-        const url = tf_backend.getRouter().pluginRoute('scalars', '/tags');
+        const url = tf_backend
+          .getRouter()
+          .pluginRoute(
+            'scalars',
+            '/tags',
+            new URLSearchParams({experiment: tf_backend.getExperimentId()})
+          );
         return this._requestManager.request(url).then((runToTagInfo) => {
           if (_.isEqual(runToTagInfo, this._runToTagInfo)) {
             // No need to update anything if there are no changes.
@@ -345,10 +351,11 @@ <h3>No scalar data was found.</h3>
           selectedRuns,
           query
         );
+        const experiment = tf_backend.getExperimentId();
         categories.forEach((category) => {
           category.items = category.items.map((item) => ({
             tag: item.tag,
-            series: item.runs.map((run) => ({run, tag: item.tag})),
+            series: item.runs.map((run) => ({run, tag: item.tag, experiment})),
           }));
         });
         this.updateArrayProp('_categories', categories, this._getCategoryKey);