Sending scheduled report via email

[cvrdev]

Bug description

Hello,

I have configured sending a report via email in scheduler. The sending is correctly triggered but it fails always with an error (see the screenshot). I use docker installation downloaded form master branch. I use default configuration, did not change anything yet. But it seems to be some problem with browser inside of the container. I tried also to install full firefox-esr inside of container but it did not help. I have not found any solution for this issue on any web source.

Regards,

Luděk

Screenshots/recordings

Superset version

master / latest-dev

Python version

I don't know

Node version

I don't know

Browser

Not applicable

Additional context

No response

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

[dosubot[bot]]

Hi @cvrdev! I'm Dosu and I’m helping the superset team.

Your error is likely caused by a mismatch or missing configuration for the headless browser inside your Docker worker container. Superset relies on Selenium WebDriver (with Firefox/Chrome) for generating report screenshots, and the default Docker image does not include a browser or driver by default. The AttributeError about 'capabilities' usually means the WebDriver configuration is not matching what Selenium expects, or the browser/driver is missing or misconfigured [source].

How to fix:

1. Install a headless browser and driver in your worker container.
   The latest docs recommend using Playwright with Chrome, or you can use Firefox with geckodriver, or Chrome with chromedriver. Only the worker container needs the browser. Example Dockerfile snippets are available in the updated docs [source].

2. Check your superset_config.py for the correct WebDriver configuration.
   For Firefox, the default config is:

   WEBDRIVER_TYPE = "firefox"
   WEBDRIVER_CONFIGURATION = {
       "options": {"capabilities": {}, "preferences": {}, "binary_location": ""},
       "service": {"log_output": "/dev/null", "service_args": [], "port": 0, "env": {}},
   }
   WEBDRIVER_OPTION_ARGS = ["--headless"]

   For Chrome, set:

   WEBDRIVER_TYPE = "chrome"
   WEBDRIVER_OPTION_ARGS = [
       "--force-device-scale-factor=2.0",
       "--high-dpi-support=2.0",
       "--headless",
       "--disable-gpu",
       "--disable-dev-shm-usage",
       "--no-sandbox",
       "--disable-setuid-sandbox",
       "--disable-extensions",
   ]

3. Verify the browser and driver are installed and accessible.
   Enter your worker container and run firefox --headless and geckodriver (or chromedriver for Chrome) to confirm they start without errors [source].

4. If using the Docker dev environment, set ALERT_REPORTS_NOTIFICATION_DRY_RUN = False in your config to actually send emails, not just simulate them [source].

5. Restart your worker container after making these changes.

If you still see the AttributeError, double-check that your WEBDRIVER_CONFIGURATION matches the expected structure and that the browser/driver versions are compatible with your Selenium version [source].

More details and example Dockerfiles are in the updated documentation:
#34908

Let me know if you need a specific example for your Dockerfile or config!

To reply, just mention @dosu.

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[dosubot[bot]]

Your error is likely caused by a misconfiguration in the WebDriver settings for screenshot generation in Superset. The default Docker config uses "log_output" in the WEBDRIVER_CONFIGURATION dictionary, but Selenium expects "log_path" instead. To fix this, update your superset_config.py so the service section uses "log_path":

WEBDRIVER_CONFIGURATION = {
    "service": {
        "executable_path": "/usr/local/bin/chromedriver",  # or geckodriver for Firefox
        "log_path": "/var/log/superset",
        "service_args": [],
        "port": 0,
        "env": {},
    },
    "options": {
        "capabilities": {},
        "preferences": {},
        "binary_location": "",
    },
}

Reference

If you use Chrome, make sure both Chrome and chromedriver are installed in your worker container. For Firefox, install both firefox-esr and geckodriver. Only the worker container needs the browser for scheduled reports. You can verify installation by running firefox --headless or chromedriver --version inside the container. Reference

If you’re on Superset >=4.1.x, consider switching to Playwright with Chrome for more reliable screenshot generation. This requires installing Playwright and enabling the PLAYWRIGHT_REPORTS_AND_THUMBNAILS feature flag in your config. Reference

Also, check that ALERT_REPORTS_NOTIFICATION_DRY_RUN is set to False in your worker container environment, or reports will appear dispatched but not actually be sent. Reference

Let me know if you need example Dockerfile snippets or more details on browser installation!

To reply, just mention @dosu.

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[cvrdev]

Hello,

thanks for the advice. I installed all suggested components for Firefox inside the container:

and changed the configuration in app/superset/config.py:

Unfortunately no progress, there is still same error :-(

Luděk

[dosubot[bot]]

Your configuration changes aren't being applied because in Docker Compose setups, Superset only loads custom configs from docker/pythonpath_dev/superset_config_docker.py—not from app/superset/config.py or similar paths. You should copy your config (for example, from docker/pythonpath_dev/superset_config_local.example) to docker/pythonpath_dev/superset_config_docker.py and put your WEBDRIVER_CONFIGURATION there. This will ensure Superset actually uses your settings for Selenium and resolves the AttributeError you’re seeing. More details are in the official Docker docs and config loader code.

Also, double-check that your WEBDRIVER_CONFIGURATION matches the expected structure: the service section should use log_path (not log_output), and the options section should be a dictionary with capabilities and preferences keys. Superset’s code expects these to be set on a Selenium Options object, not as a plain dict—so the config must be loaded correctly for this to work (reference).

Let me know if you need an example config file or further help!

To reply, just mention @dosu.

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[cvrdev]

I copied the example file and updated it to contain the driver definition. Then I rebuild, restarted and reinstalled the worker container but there is no change. Still same error.

It there some image on Docker Hub that contains already everything necessary where it is working and it is necessary only to configure the email connection? There are thousands images and I am not sure about the purpose.

[dosubot[bot]]

There isn't an official Docker image on Docker Hub that includes everything needed for scheduled reports (browsers, drivers, etc.) out-of-the-box—you always need to do some manual setup or use a custom Dockerfile. The current -dev images (like apache/superset:5.0.0-dev) no longer include Firefox or geckodriver by default, only Chromium for Playwright support, to keep the image smaller and builds faster. If you need Firefox/geckodriver, you have to extend the image yourself with a Dockerfile that installs them, as shown in the official docs and this issue.

For most setups, it's easier and more reliable to use Chromium/Chrome for screenshots. Set WEBDRIVER_TYPE = "chrome" in your config and make sure Chrome and ChromeDriver are installed in your worker container. If you want to use Playwright (recommended for Superset >=4.1.x), enable the PLAYWRIGHT_REPORTS_AND_THUMBNAILS feature flag and use the latest -dev image, which already includes Playwright and Chromium.

Make sure your custom config is in docker/pythonpath_dev/superset_config_docker.py and not elsewhere, and double-check that your WEBDRIVER_CONFIGURATION uses log_path (not log_output) in the service section. If you need a working example Dockerfile or config snippet, let me know!

To reply, just mention @dosu.

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[cvrdev]

Working example Dockerfile would be appreciated. Thanks. As Chrome is not part of Debian repositories, is it OK to install Chromium instead of Chrome to use it for screenshots?

[dosubot[bot]]

You can use Chromium from the Debian repositories for Superset scheduled report screenshots—just set WEBDRIVER_TYPE = "chrome" in your config and make sure both Chromium and the matching ChromeDriver are installed in your worker container. Superset's code treats Chromium and Chrome identically for Selenium; the only requirement is that the driver and browser versions match, and you may need to set the binary_location if the Chromium binary isn't in the default path. This setup is widely used and works reliably, but it's not officially documented or guaranteed by Superset maintainers, so you should verify it in your environment (reference).

Here’s a minimal working Dockerfile example for a Superset worker with Chromium and ChromeDriver:

FROM apache/superset:latest

USER root

# Install Chromium and dependencies
RUN apt-get update && \
    apt-get install -y chromium chromium-driver && \
    ln -sf /usr/bin/chromium /usr/bin/chrome && \
    ln -sf /usr/bin/chromium-driver /usr/bin/chromedriver

USER superset

And in your superset_config_docker.py:

WEBDRIVER_TYPE = "chrome"
WEBDRIVER_OPTION_ARGS = [
    "--headless",
    "--disable-gpu",
    "--disable-dev-shm-usage",
    "--no-sandbox",
    "--disable-setuid-sandbox",
    "--disable-extensions",
]
WEBDRIVER_CONFIGURATION = {
    "service": {
        "executable_path": "/usr/bin/chromedriver",
        "log_path": "/dev/null",
        "service_args": [],
        "port": 0,
        "env": {},
    },
    "options": {
        "capabilities": {},
        "preferences": {},
        "binary_location": "/usr/bin/chromium",  # or leave empty if default
    },
}

This setup works for most users. If you run into issues, double-check that the versions of Chromium and ChromeDriver match, and that the paths are correct. For more details and troubleshooting tips, see the official Superset docs.

To reply, just mention @dosu.

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[cvrdev]

Thank you, @dosu, for the code. i followed exactly your instructions. In the Docker file you can remove line "ln -sf /usr/bin/chromium-driver /usr/bin/chromedriver" as the chromium-driver is installed in Debian 13 directly with name chromedriver and the link command deletes it. Now I have both driver and chromium in container installed. Unfortunately taking screenshots still does not work, but error is now different: