Find identity providers by brand name when unique.

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/config/mod.rs

@@ -2525,8 +2525,13 @@ pub struct IdentityProvider {
 	/// for your convenience. For certain brands we apply essential internal
 	/// workarounds specific to that provider; it is important to configure this
 	/// field properly when a provider needs to be recognized (like GitHub for
-	/// example). Several configured providers can share the same brand name. It
-	/// is not case-sensitive.
+	/// example).
+	///
+	/// Several configured providers can share the same brand name. It is not
+	/// case-sensitive. As a convenience for common simple deployments we can
+	/// identify this provider by brand in addition to the unique `client_id` if
+	/// and only if there is a single provider for the brand; see notes for
+	/// `client_id`.
 	#[serde(deserialize_with = "utils::string::de::to_lowercase")]
 	pub brand: String,
 
@@ -2534,6 +2539,11 @@ pub struct IdentityProvider {
 	/// registration. This ID then uniquely identifies this configuration
 	/// instance itself, becoming the identity provider's ID and must be unique
 	/// and remain unchanged.
+	///
+	/// As a convenience we also identify this config by `brand` if and only if
+	/// there is a single provider configured for a `brand`. Note carefully that
+	/// multiple providers configured with the same `brand` is not an error and
+	/// this provider will simply not be found when querying by `brand`.
 	pub client_id: String,
 
 	/// Secret key the provider generated for you along with the `client_id`

src/service/oauth/providers.rs

@@ -28,33 +28,80 @@ pub(super) fn build(args: &crate::Args<'_>) -> Self {
 #[implement(Providers)]
 #[tracing::instrument(level = "debug", skip(self))]
 pub async fn get(&self, id: &str) -> Result<Provider> {
-	if let Some(provider) = self.providers.read().await.get(id).cloned() {
+	if let Some(provider) = self.get_cached(id).await {
 		return Ok(provider);
 	}
 
 	let config = self.get_config(id)?;
+	let id = config.id().to_owned();
 	let mut map = self.providers.write().await;
-	let config = self.configure(config).await?;
+	let provider = self.configure(config).await?;
 
-	debug!(?id, ?config);
-	_ = map.insert(id.into(), config.clone());
+	debug!(?id, ?provider);
+	_ = map.insert(id, provider.clone());
 
-	Ok(config)
+	Ok(provider)
 }
 
 /// Get the admin-configured Provider which exists prior to any
 /// reconciliation with the well-known discovery (the server's config is
 /// immutable); though it is important to note the server config can be
 /// reloaded. This will Err NotFound for a non-existent idp.
+///
+/// When no provider is found with a matching client_id, providers are then
+/// searched by brand. Brand matching will be invalidated when more than one
+/// provider matches the brand.
 #[implement(Providers)]
 pub fn get_config(&self, id: &str) -> Result<Provider> {
-	self.services
-		.config
-		.identity_provider
+	let providers = &self.services.config.identity_provider;
+
+	if let Some(provider) = providers
 		.iter()
 		.find(|config| config.id() == id)
 		.cloned()
-		.ok_or_else(|| err!(Request(NotFound("Unrecognized Identity Provider"))))
+	{
+		return Ok(provider);
+	}
+
+	if let Some(provider) = providers
+		.iter()
+		.find(|config| config.brand == id.to_lowercase())
+		.filter(|_| {
+			providers
+				.iter()
+				.filter(|config| config.brand == id.to_lowercase())
+				.count()
+				.eq(&1)
+		})
+		.cloned()
+	{
+		return Ok(provider);
+	}
+
+	Err!(Request(NotFound("Unrecognized Identity Provider")))
+}
+
+/// Get the discovered provider from the runtime cache. ID may be client_id or
+/// brand if brand is unique among provider configurations.
+#[implement(Providers)]
+async fn get_cached(&self, id: &str) -> Option<Provider> {
+	let providers = self.providers.read().await;
+
+	if let Some(provider) = providers.get(id).cloned() {
+		return Some(provider);
+	}
+
+	providers
+		.values()
+		.find(|provider| provider.brand == id.to_lowercase())
+		.filter(|_| {
+			providers
+				.values()
+				.filter(|provider| provider.brand == id.to_lowercase())
+				.count()
+				.eq(&1)
+		})
+		.cloned()
 }
 
 /// Configure an identity provider; takes the admin-configured instance from the

tuwunel-example.toml

@@ -2141,8 +2141,13 @@
 # for your convenience. For certain brands we apply essential internal
 # workarounds specific to that provider; it is important to configure this
 # field properly when a provider needs to be recognized (like GitHub for
-# example). Several configured providers can share the same brand name. It
-# is not case-sensitive.
+# example).
+#
+# Several configured providers can share the same brand name. It is not
+# case-sensitive. As a convenience for common simple deployments we can
+# identify this provider by brand in addition to the unique `client_id` if
+# and only if there is a single provider for the brand; see notes for
+# `client_id`.
 #
 #brand =
 
@@ -2151,6 +2156,11 @@
 # instance itself, becoming the identity provider's ID and must be unique
 # and remain unchanged.
 #
+# As a convenience we also identify this config by `brand` if and only if
+# there is a single provider configured for a `brand`. Note carefully that
+# multiple providers configured with the same `brand` is not an error and
+# this provider will simply not be found when querying by `brand`.
+#
 #client_id =
 
 # Secret key the provider generated for you along with the `client_id`