Skip to main content

Python

Connect directly to Foxglove or play back local data recorded with the Python SDK.

Install the SDK​

The SDK is distributed through PyPI. You can get started with a new project or use Foxglove from a notebook.

Install foxglove-sdk from PyPI: https://pypi.org/project/foxglove-sdk

pip install foxglove-sdk

The exact installation will depend on your package manager; here's an example using poetry.

poetry new example
poetry add foxglove-sdk

Live data​

Log messages from Python​

Create a new file in your project (for example, src/example/main.py)

import foxglove
import time

foxglove.start_server()

while True:
    foxglove.log("/hello", {"time": time.time()})
    time.sleep(0.03)

Run the script​

Run the script to start logging. Following the poetry example above, you can run the following command from the "example" directory:

poetry run python src/example/main.py

Connect​

In Foxglove, select "Open connection" from the dashboard or left-hand menu.

Select open connection

Select "Foxglove WebSocket" in the "Open a new connection" dialog, then click "Open" to accept the default connection string:

Foxglove WebSocket dialog

Local data​

Recording data to a file​

The SDK can also log data to disk. Let's augment the example above to also produce an MCAP file which can later be opened in Foxglove:

import foxglove
import time

foxglove.start_server()

# Keep a reference to the mcap. It will automatically close the file when the program exits, but
# we could also close it manually with `mcap.close()`.
mcap = foxglove.open_mcap("example.mcap")

while True:
    foxglove.log("/hello", {"time": time.time()})
    time.sleep(0.03)

Viewing data from a file​

To load local files for visualization, you can:

  • Click "Open local file(s)…" in the dashboard or left-hand menu
  • Open or drag-and-drop the files from your OS file manager (desktop only)

Local file dialog

note

When opening multiple files, Foxglove will merge the data into a single playback timeline.

You can only merge multiple files of the same format.

Imported data​

After importing data to Foxglove, select individual resources to visualize on the Recordings or Events pages:

Visualize on Recordings page

Select a custom time range of data (can span multiple recordings or events) to visualize on the Timeline page: