Run events every given number of seconds

CHANGELOG.md

@@ -1,7 +1,52 @@
 # Upcoming Release 
 
 ## New Features:
-No changes to highlight.
+
+### Running Events Continuously
+Gradio now supports the ability to run an event continuously on a fixed schedule. To use this feature,
+pass `every=# of seconds` to the event definition. This will run the event every given number of seconds!
+
+This can be used to:
+* Create live visualizations that show the most up to date data 
+* Refresh the state of the frontend automatically in response to changes in the backend
+
+Here is an example of a live plot that refreshes every half second:
+```python
+import math
+import gradio as gr
+import plotly.express as px
+import numpy as np
+
+
+plot_end = 2 * math.pi
+
+
+def get_plot(period=1):
+    global plot_end
+    x = np.arange(plot_end - 2 * math.pi, plot_end, 0.02)
+    y = np.sin(2*math.pi*period * x)
+    fig = px.line(x=x, y=y)
+    plot_end += 2 * math.pi
+    return fig
+
+
+with gr.Blocks() as demo:
+    with gr.Row():
+        with gr.Column():
+            gr.Markdown("Change the value of the slider to automatically update the plot")
+            period = gr.Slider(label="Period of plot", value=1, minimum=0, maximum=10, step=1)
+            plot = gr.Plot(label="Plot (updates every half second)")
+
+    dep = demo.load(get_plot, None, plot, every=0.5)
+    period.change(get_plot, period, plot, every=0.5, cancels=[dep])
+
+demo.queue().launch()
+```
+
+![live_demo](https://user-images.githubusercontent.com/41651716/198357377-633ce460-4e31-47bd-8202-1440cdd6fe19.gif)
+
+
+
 
 ## Bug Fixes:
 * Apply appropriate alt text to all gallery images. [@camenduru](https://github.com/camenduru) in [PR 2358](https://github.com/gradio-app/gradio/pull/2538)
@@ -15,7 +60,7 @@ No changes to highlight.
 No changes to highlight.
 
 ## Full Changelog:
-No changes to highlight.
+* Added the `every` keyword to event listeners that runs events on a fixed schedule by [@freddyaboulton](https://github.com/freddyaboulton) in [PR 2512](https://github.com/gradio-app/gradio/pull/2512)
 
 ## Contributors Shoutout:
 No changes to highlight.

demo/live_dashboard/requirements.txt

@@ -0,0 +1 @@
+plotly

demo/live_dashboard/run.py

@@ -0,0 +1,42 @@
+import math
+import gradio as gr
+import datetime
+import plotly.express as px
+import numpy as np
+
+
+def get_time():
+    return datetime.datetime.now()
+
+
+plot_end = 2 * math.pi
+
+
+def get_plot(period=1):
+    global plot_end
+    x = np.arange(plot_end - 2 * math.pi, plot_end, 0.02)
+    y = np.sin(2*math.pi*period * x)
+    fig = px.line(x=x, y=y)
+    plot_end += 2 * math.pi
+    return fig
+
+
+with gr.Blocks() as demo:
+    with gr.Row():
+        with gr.Column():
+            c_time2 = gr.Textbox(label="Current Time refreshed every second")
+            gr.Markdown("Change the value of the slider to automatically update the plot")
+            period = gr.Slider(label="Period of plot", value=1, minimum=0, maximum=10, step=1)
+            plot = gr.Plot(label="Plot (updates every half second)")
+        with gr.Column():
+            name = gr.Textbox(label="Enter your name")
+            greeting = gr.Textbox(label="Greeting")
+            button = gr.Button(value="Greet")
+            button.click(lambda s: f"Hello {s}", name, greeting)
+
+    demo.load(lambda: datetime.datetime.now(), None, c_time2, every=1)
+    dep = demo.load(get_plot, None, plot, every=0.5)
+    period.change(get_plot, period, plot, every=0.5, cancels=[dep])
+
+if __name__ == "__main__":
+    demo.queue().launch()

gradio/blocks.py

@@ -46,7 +46,12 @@
     set_documentation_group,
 )
 from gradio.exceptions import DuplicateBlockError
-from gradio.utils import component_or_layout_class, delete_none, get_cancel_function
+from gradio.utils import (
+    component_or_layout_class,
+    delete_none,
+    get_cancel_function,
+    get_continuous_fn,
+)
 
 set_documentation_group("blocks")
 
@@ -134,6 +139,7 @@ def set_event_trigger(
         batch: bool = False,
         max_batch_size: int = 4,
         cancels: List[int] | None = None,
+        every: int | None = None,
     ) -> Dict[str, Any]:
         """
         Adds an event to the component's dependencies.
@@ -163,10 +169,22 @@ def set_event_trigger(
             inputs = [inputs]
         if not isinstance(outputs, list):
             outputs = [outputs]
+
         if Context.root_block is None:
             raise AttributeError(
                 f"{event_name}() and other events can only be called within a Blocks context."
             )
+        if every is not None and every <= 0:
+            raise ValueError("Parameter every must be positive or None")
+        if every and batch:
+            raise ValueError(
+                f"Cannot run {event_name} event in a batch and every {every} seconds. "
+                "Either batch is True or every is non-zero but not both."
+            )
+
+        if every:
+            fn = get_continuous_fn(fn, every)
+
         Context.root_block.fns.append(BlockFunction(fn, preprocess, postprocess))
         if api_name is not None:
             api_name_ = utils.append_unique_suffix(
@@ -177,6 +195,7 @@ def set_event_trigger(
                     "api_name {} already exists, using {}".format(api_name, api_name_)
                 )
                 api_name = api_name_
+
         dependency = {
             "targets": [self._id] if not no_target else [],
             "trigger": event_name,
@@ -188,6 +207,7 @@ def set_event_trigger(
             "api_name": api_name,
             "scroll_to_output": scroll_to_output,
             "show_progress": show_progress,
+            "every": every,
             "batch": batch,
             "max_batch_size": max_batch_size,
             "cancels": cancels or [],
@@ -885,7 +905,6 @@ async def process_api(
             data = [self.postprocess_data(fn_index, o, state) for o in zip(*preds)]
             data = list(zip(*data))
             is_generating, iterator = None, None
-
         else:
             inputs = self.preprocess_data(fn_index, inputs, state)
             iterator = iterators.get(fn_index, None) if iterators else None
@@ -983,8 +1002,9 @@ def load(
         api_key: Optional[str] = None,
         alias: Optional[str] = None,
         _js: Optional[str] = None,
+        every: None | int = None,
         **kwargs,
-    ) -> Blocks | None:
+    ) -> Blocks | Dict[str, Any] | None:
         """
         For reverse compatibility reasons, this is both a class method and an instance
         method, the two of which, confusingly, do two completely different things.
@@ -1002,6 +1022,7 @@ def load(
             fn: Instance Method - Callable function
             inputs: Instance Method - input list
             outputs: Instance Method - output list
+            every: Run this event 'every' number of seconds. Interpreted in seconds. Queue must be enabled.
         Example:
             import gradio as gr
             import datetime
@@ -1026,13 +1047,14 @@ def get_time():
                 kwargs["outputs"] = outputs
             return external.load_blocks_from_repo(name, src, api_key, alias, **kwargs)
         else:
-            self_or_cls.set_event_trigger(
+            return self_or_cls.set_event_trigger(
                 event_name="load",
                 fn=fn,
                 inputs=inputs,
                 outputs=outputs,
-                no_target=True,
                 js=_js,
+                no_target=True,
+                every=every,
             )
 
     def clear(self):