developers.home-assistant/docs/config_entries_config_flow_handler.md

title
Config flow

Integrations can be set up via the user interface by adding support for a config flow to create a config entry. Components that want to support config entries will need to define a Config Flow Handler. This handler will manage the creation of entries from user input, discovery or other sources (like Home Assistant OS).

Config Flow Handlers control the data that is stored in a config entry. This means that there is no need to validate that the config is correct when Home Assistant starts up. It will also prevent breaking changes because we will be able to migrate configuration entries to new formats if the version changes.

When instantiating the handler, Home Assistant will make sure to load all dependencies and install the requirements of the component.

Updating the manifest

You need to update your integrations manifest to inform Home Assistant that your integration has a config flow. This is done by adding config_flow: true to your manifest (docs).

Defining your config flow

Config entries use the data flow entry framework to define their config flows. The config flow needs to be defined in the file config_flow.py in your integration folder, extend homeassistant.config_entries.ConfigFlow and pass a domain key as part of inheriting ConfigFlow.

from homeassistant import config_entries
from .const import DOMAIN


class ExampleConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
    """Example config flow."""
    # The schema version of the entries that it creates
    # Home Assistant will call your migrate method if the version changes
    VERSION = 1
    MINOR_VERSION = 1

Once you have updated your manifest and created the config_flow.py, you will need to run python3 -m script.hassfest (one time only) for Home Assistant to activate the config entry for your integration.

Config flow title

The title of a config flow can be influenced by integrations, and is determined in this priority order:

1. If title_placeholders is set to a non-empty dictionary in the config flow, it will be used to dynamically calculate the config flow's title. Reauth and reconfigure flows automatically set title_placeholders to {"name": config_entry_title}.
   1. If the integration provides a localized flow_title, that will be used, with any translation placeholders substituted from the title_placeholders.
   2. If the integration does not provide a flow_title but the title_placeholders includes a name, the name will be used as the flow's title.
2. Set the flow title to the integration's localized title, if it exists.
3. Set the flow title to the integration manifest's name, if it exists.
4. Set the flow title to the integration's domain.

Note that this priority order means that:

• A localized flow_title is ignored if the title_placeholders dictionary is missing or empty, even if the localized flow_title does not have any placeholders
• If title_placeholders is not empty, but there's no localized flow_title and the title_placeholders does not include a name, it is ignored.

Defining steps

Your config flow will need to define steps of your configuration flow. Each step is identified by a unique step name (step_id). The step callback methods follow the pattern async_step_<step_id>. The docs for Data Entry Flow describe the different return values of a step. Here is an example of how to define the user step:

import voluptuous as vol

class ExampleConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
    async def async_step_user(self, info):
        if info is not None:
            pass  # TODO: process info

        return self.async_show_form(
            step_id="user", data_schema=vol.Schema({vol.Required("password"): str})
        )

There are a few step names reserved for system use:

Step name	Description
bluetooth	Invoked if your integration has been discovered via Bluetooth as specified using bluetooth in the manifest.
discovery	DEPRECATED Invoked if your integration has been discovered and the matching step has not been defined.
dhcp	Invoked if your integration has been discovered via DHCP as specified using dhcp in the manifest.
hassio	Invoked if your integration has been discovered via a Supervisor add-on.
homekit	Invoked if your integration has been discovered via HomeKit as specified using homekit in the manifest.
mqtt	Invoked if your integration has been discovered via MQTT as specified using mqtt in the manifest.
ssdp	Invoked if your integration has been discovered via SSDP/uPnP as specified using ssdp in the manifest.
usb	Invoked if your integration has been discovered via USB as specified using usb in the manifest.
user	Invoked when a user initiates a flow via the user interface or when discovered and the matching and discovery step are not defined.
reconfigure	Invoked when a user initiates a flow to reconfigure an existing config entry via the user interface.
zeroconf	Invoked if your integration has been discovered via Zeroconf/mDNS as specified using zeroconf in the manifest.
reauth	Invoked if your integration indicates it requires reauthentication, e.g., due to expired credentials.
import	Reserved for migrating from YAML configuration to config entries.

Unique IDs

A config flow can attach a unique ID, which must be a string, to a config flow to avoid the same device being set up twice.

By setting a unique ID, users will have the option to ignore the discovery of your config entry. That way, they won't be bothered about it anymore. If the integration uses Bluetooth, DHCP, HomeKit, Zeroconf/mDNS, USB, or SSDP/uPnP to be discovered, supplying a unique ID is required.

If a unique ID isn't available, alternatively, the bluetooth, dhcp, zeroconf, hassio, homekit, ssdp, usb, and discovery steps can be omitted, even if they are configured in the integration manifest. In that case, the user step will be called when the item is discovered.

Alternatively, if an integration can't get a unique ID all the time (e.g., multiple devices, some have one, some don't), a helper is available that still allows for discovery, as long as there aren't any instances of the integration configured yet.

Here's an example of how to handle discovery where a unique ID is not always available:

if device_unique_id:
    await self.async_set_unique_id(device_unique_id)
else:
    await self._async_handle_discovery_without_unique_id()

Managing Unique IDs in Config Flows

When a unique ID is set, the flow will immediately abort if another flow is in progress for this unique ID. You can also quickly abort if there is already an existing config entry for this ID. Config entries will get the unique ID of the flow that creates them.

Call inside a config flow step:

# Assign a unique ID to the flow and abort the flow
# if another flow with the same unique ID is in progress
await self.async_set_unique_id(device_unique_id)

# Abort the flow if a config entry with the same unique ID exists
self._abort_if_unique_id_configured()

Should the config flow then abort, the text resource with the key already_configured from the abort part of your strings.json will be displayed to the user in the interface as an abort reason.

{
  "config": {
    "abort": {
      "already_configured": "Device is already configured"
    }
  }
}

Unique ID requirements

A unique ID is used to match a config entry to the underlying device or API. The unique ID must be stable, should not be able to be changed by the user and must be a string.

The Unique ID can be used to update the config entry data when device access details change. For example, for devices that communicate over the local network, if the IP address changes due to a new DHCP assignment, the integration can use the Unique ID to update the host using the following code snippet:

    await self.async_set_unique_id(serial_number)
    self._abort_if_unique_id_configured(updates={CONF_HOST: host, CONF_PORT: port})

Example acceptable sources for a unique ID

• Serial number of a device
• MAC address: formatted using homeassistant.helpers.device_registry.format_mac; Only obtain the MAC address from the device API or a discovery handler. Tools that rely on reading the arp cache or local network access such as getmac will not function in all supported network environments and are not acceptable.
• A string representing the latitude and longitude or other unique geo location
• Unique identifier that is physically printed on the device or burned into an EEPROM

Sometimes acceptable sources for a unique ID for local devices

• Hostname: If a subset of the hostname contains one of the acceptable sources, this portion can be used

Sometimes acceptable sources for a unique ID for cloud services

• Email Address: Must be normalized to lowercase
• Username: Must be normalized to lowercase if usernames are case-insensitive.
• Account ID: Must not have collisions

Unacceptable sources for a unique ID

• IP Address
• Device Name
• Hostname if it can be changed by the user
• URL

Discovery steps

When an integration is discovered, their respective discovery step is invoked (ie async_step_dhcp or async_step_zeroconf) with the discovery information. The step will have to check the following things:

• Make sure there are no other instances of this config flow in progress of setting up the discovered device. This can happen if there are multiple ways of discovering that a device is on the network.
  • In most cases, it's enough to set the unique ID on the flow and check if there's already a config entry with the same unique ID as explained in the section about managing unique IDs in config flows
  • In some cases, a unique ID can't be determined, or the unique ID is ambiguous because different discovery sources may have different ways to calculate it. In such cases:
    1. Implement the method def is_matching(self, other_flow: Self) -> bool on the flow.
    2. Call hass.config_entries.flow.async_has_matching_flow(self).
    3. Your flow's is_matching method will then be called once for each other ongoing flow.
• Make sure that the device is not already set up.
• Invoking a discovery step should never result in a finished flow and a config entry. Always confirm with the user.

Discoverable integrations that require no authentication

If your integration is discoverable without requiring any authentication, you'll be able to use the Discoverable Flow that is built-in. This flow offers the following features:

• Detect if devices/services can be discovered on the network before finishing the config flow.
• Support all manifest-based discovery protocols.
• Limit to only 1 config entry. It is up to the config entry to discover all available devices.

To get started, run python3 -m script.scaffold config_flow_discovery and follow the instructions. This will create all the boilerplate necessary to configure your integration using discovery.

Configuration via OAuth2

Home Assistant has built-in support for integrations that offer account linking using the OAuth2 authorization framework. To be able to leverage this, you will need to structure your Python API library in a way that allows Home Assistant to be responsible for refreshing tokens. See our API library guide on how to do this.

The built-in OAuth2 support works out of the box with locally configured client ID / secret using the Application Credentials platform and with the Home Assistant Cloud Account Linking service. This service allows users to link their account with a centrally managed client ID/secret. If you want your integration to be part of this service, reach out to us at hello@home-assistant.io.

To get started, run python3 -m script.scaffold config_flow_oauth2 and follow the instructions. This will create all the boilerplate necessary to configure your integration using OAuth2.

Translations

Translations for the config flow handlers are defined under the config key in the component translation file strings.json. Example of the Hue component:

{
  "title": "Philips Hue Bridge",
  "config": {
    "step": {
      "init": {
        "title": "Pick Hue bridge",
        "data": {
          "host": "Host"
        }
      },
      "link": {
        "title": "Link Hub",
        "description": "Press the button on the bridge to register Philips Hue with Home Assistant.\n\n![Location of button on bridge](/static/images/config_philips_hue.jpg)"
      }
    },
    "error": {
      "register_failed": "Failed to register, please try again",
      "linking": "Unknown linking error occurred."
    },
    "abort": {
      "discover_timeout": "Unable to discover Hue bridges",
      "no_bridges": "No Philips Hue bridges discovered",
      "all_configured": "All Philips Hue bridges are already configured",
      "unknown": "Unknown error occurred",
      "cannot_connect": "Unable to connect to the bridge",
      "already_configured": "Bridge is already configured"
    }
  }
}

When the translations are merged into Home Assistant, they will be automatically uploaded to Lokalise where the translation team will help to translate them in other languages. While developing locally, you will need to run python3 -m script.translations develop to see changes made to strings.json More info on translating Home Assistant.

Config entry migration

As mentioned above - each Config Entry has a version assigned to it. This is to be able to migrate Config Entry data to new formats when Config Entry schema changes.

Migration can be handled programatically by implementing function async_migrate_entry in your component's __init__.py file. The function should return True if migration is successful.

The version is made of a major and minor version. If minor versions differ but major versions are the same, integration setup will be allowed to continue even if the integration does not implement async_migrate_entry. This means a minor version bump is backwards compatible unlike a major version bump which causes the integration to fail setup if the user downgrades Home Assistant Core without restoring their configuration from backup.

# Example migration function
async def async_migrate_entry(hass, config_entry: ConfigEntry):
    """Migrate old entry."""
    _LOGGER.debug("Migrating configuration from version %s.%s", config_entry.version, config_entry.minor_version)

    if config_entry.version > 1:
        # This means the user has downgraded from a future version
        return False

    if config_entry.version == 1:

        new_data = {**config_entry.data}
        if config_entry.minor_version < 2:
            # TODO: modify Config Entry data with changes in version 1.2
            pass
        if config_entry.minor_version < 3:
            # TODO: modify Config Entry data with changes in version 1.3
            pass

        hass.config_entries.async_update_entry(config_entry, data=new_data, minor_version=3, version=1)

    _LOGGER.debug("Migration to configuration version %s.%s successful", config_entry.version, config_entry.minor_version)

    return True

Reconfigure

A config entry can allow reconfiguration by adding a reconfigure step. This provides a way for integrations to allow users to change config entry data without the need to implement an OptionsFlow for changing setup data which is not meant to be optional.

This is not meant to handle authentication issues or reconfiguration of such. For that we have the reauth step, which should be implemented to automatically start in such case there is an issue with authentication.

import voluptuous as vol

class ExampleConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
    """Config flow for Example integration."""

    async def async_step_reconfigure(self, user_input: dict[str, Any] | None = None):
        if user_input is not None:
            # TODO: process user input
            self.async_set_unique_id(user_id)
            self._abort_if_unique_id_mismatch()
            return self.async_update_reload_and_abort(
                self._get_reconfigure_entry(),
                data_updates=data,
            )

        return self.async_show_form(
            step_id="reconfigure",
            data_schema=vol.Schema({vol.Required("input_parameter"): str}),
        )

On success, reconfiguration flows are expected to update the current entry and abort; they should not create a new entry. This is usually done with the return self.async_update_reload_and_abort helper. Automated tests should verify that the reconfigure flow updates the existing config entry and does not create additional entries.

Checking whether you are in a reconfigure flow can be done using if self.source == SOURCE_RECONFIGURE. It is also possible to access the corresponding config entry using self._get_reconfigure_entry(). Ensuring that the unique_id is unchanged should be done using await self.async_set_unique_id followed by self._abort_if_unique_id_mismatch().

Reauthentication

Gracefully handling authentication errors such as invalid, expired, or revoked tokens is needed to advance on the Integration Quality Scale. This example of how to add reauth to the OAuth flow created by script.scaffold following the pattern in Building a Python library. If you are looking for how to trigger the reauthentication flow, see handling expired credentials.

This example catches an authentication exception in config entry setup in __init__.py and instructs the user to visit the integrations page in order to reconfigure the integration.

To allow the user to change config entry data which is not optional (OptionsFlow) and not directly related to authentication, for example a changed host name, integrations should implement the reconfigure step.

from homeassistant.config_entries import SOURCE_REAUTH, ConfigEntry
from homeassistant.core import HomeAssistant
from . import api

async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry):
    """Setup up a config entry."""

    # TODO: Replace with actual API setup and exception
    auth = api.AsyncConfigEntryAuth(...)
    try:
        await auth.refresh_tokens()
    except TokenExpiredError as err:
        raise ConfigEntryAuthFailed(err) from err

    # TODO: Proceed with component setup

The flow handler in config_flow.py also needs to have some additional steps to support reauth which include showing a confirmation, starting the reauth flow, updating the existing config entry, and reloading to invoke setup again.

class OAuth2FlowHandler(
    config_entry_oauth2_flow.AbstractOAuth2FlowHandler, domain=DOMAIN
):
    """Config flow to handle OAuth2 authentication."""

    async def async_step_reauth(
        self, entry_data: Mapping[str, Any]
    ) -> ConfigFlowResult:
        """Perform reauth upon an API authentication error."""
        return await self.async_step_reauth_confirm()

    async def async_step_reauth_confirm(
        self, user_input: dict[str, Any] | None = None
    ) -> ConfigFlowResult:
        """Dialog that informs the user that reauth is required."""
        if user_input is None:
            return self.async_show_form(
                step_id="reauth_confirm",
                data_schema=vol.Schema({}),
            )
        return await self.async_step_user()

    async def async_oauth_create_entry(self, data: dict) -> dict:
        """Create an oauth config entry or update existing entry for reauth."""
        self.async_set_unique_id(user_id)
        if self.source == SOURCE_REAUTH:
            self._abort_if_unique_id_mismatch()
            return self.async_update_reload_and_abort(
                self._get_reauth_entry(),
                data_updates=data,
            )
        self._abort_if_unique_id_configured()
        return await super().async_oauth_create_entry(data)

By default, the async_update_reload_and_abort helper method aborts the flow with reauth_successful after update and reload. By default, the entry will always be reloaded. If the config entry only should be reloaded in case the config entry was updated, specify reload_even_if_entry_is_unchanged=False.

Depending on the details of the integration, there may be additional considerations such as ensuring the same account is used across reauth, or handling multiple config entries.

The reauth confirmation dialog needs additional definitions in strings.json for the reauth confirmation and success dialogs:

{
  "config": {
    "step": {
      "reauth_confirm": {
        "title": "[%key:common::config_flow::title::reauth%]",
        # TODO: Replace with the name of the integration
        "description": "The Example integration needs to re-authenticate your account"
      }
    },
    "abort": {
      "reauth_successful": "[%key:common::config_flow::abort::reauth_successful%]"
    },
}

See Translations local development instructions.

Authentication failures (such as a revoked oauth token) can be a little tricky to manually test. One suggestion is to make a copy of config/.storage/core.config_entries and manually change the values of access_token, refresh_token, and expires_at depending on the scenario you want to test. You can then walk advance through the reauth flow and confirm that the values get replaced with new valid tokens.

On success, reauth flows are expected to update the current entry and abort; they should not create a new entry. This is usually done with the return self.async_update_reload_and_abort helper. Automated tests should verify that the reauth flow updates the existing config entry and does not create additional entries.

Checking whether you are in a reauth flow can be done using if self.source == SOURCE_REAUTH. It is also possible to access the corresponding config entry using self._get_reauth_entry(). Ensuring that the unique_id is unchanged should be done using await self.async_set_unique_id followed by self._abort_if_unique_id_mismatch().

Testing your config flow

Integrations with a config flow require full test coverage of all code in config_flow.py to be accepted into core. Test your code includes more details on how to generate a coverage report.