Simplify ConfigurationSection trait & skip default values when serial…

…izing

This removes the `test` and `generate` methods from the
`ConfigurationSection` trait, as they did not really had a reason to
exist in the trait itself.

crates/config/Cargo.toml

@@ -14,7 +14,6 @@ workspace = true
 [dependencies]
 tokio = { version = "1.36.0", features = ["fs", "rt"] }
 tracing.workspace = true
-async-trait.workspace = true
 
 thiserror.workspace = true
 anyhow.workspace = true

crates/config/src/sections/branding.rs

@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use async_trait::async_trait;
-use rand::Rng;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use url::Url;
@@ -24,38 +22,42 @@ use crate::ConfigurationSection;
 #[derive(Clone, Debug, Deserialize, JsonSchema, Serialize, Default)]
 pub struct BrandingConfig {
     /// A human-readable name. Defaults to the server's address.
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub service_name: Option<String>,
 
     /// Link to a privacy policy, displayed in the footer of web pages and
     /// emails. It is also advertised to clients through the `op_policy_uri`
     /// OIDC provider metadata.
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub policy_uri: Option<Url>,
 
     /// Link to a terms of service document, displayed in the footer of web
     /// pages and emails. It is also advertised to clients through the
     /// `op_tos_uri` OIDC provider metadata.
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub tos_uri: Option<Url>,
 
     /// Legal imprint, displayed in the footer in the footer of web pages and
     /// emails.
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub imprint: Option<String>,
 
     /// Logo displayed in some web pages.
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub logo_uri: Option<Url>,
 }
 
-#[async_trait]
-impl ConfigurationSection for BrandingConfig {
-    const PATH: Option<&'static str> = Some("branding");
-
-    async fn generate<R>(_rng: R) -> anyhow::Result<Self>
-    where
-        R: Rng + Send,
-    {
-        Ok(Self::default())
+impl BrandingConfig {
+    /// Returns true if the configuration is the default one
+    pub(crate) fn is_default(&self) -> bool {
+        self.service_name.is_none()
+            && self.policy_uri.is_none()
+            && self.tos_uri.is_none()
+            && self.imprint.is_none()
+            && self.logo_uri.is_none()
     }
+}
 
-    fn test() -> Self {
-        Self::default()
-    }
+impl ConfigurationSection for BrandingConfig {
+    const PATH: Option<&'static str> = Some("branding");
 }

crates/config/src/sections/clients.rs

@@ -14,11 +14,9 @@
 
 use std::ops::Deref;
 
-use async_trait::async_trait;
 use figment::Figment;
 use mas_iana::oauth::OAuthClientAuthenticationMethod;
 use mas_jose::jwk::PublicJsonWebKeySet;
-use rand::Rng;
 use schemars::JsonSchema;
 use serde::{de::Error, Deserialize, Serialize};
 use ulid::Ulid;
@@ -211,6 +209,13 @@ impl ClientConfig {
 #[serde(transparent)]
 pub struct ClientsConfig(#[schemars(with = "Vec::<ClientConfig>")] Vec<ClientConfig>);
 
+impl ClientsConfig {
+    /// Returns true if all fields are at their default values
+    pub(crate) fn is_default(&self) -> bool {
+        self.0.is_empty()
+    }
+}
+
 impl Deref for ClientsConfig {
     type Target = Vec<ClientConfig>;
 
@@ -228,17 +233,9 @@ impl IntoIterator for ClientsConfig {
     }
 }
 
-#[async_trait]
 impl ConfigurationSection for ClientsConfig {
     const PATH: Option<&'static str> = Some("clients");
 
-    async fn generate<R>(_rng: R) -> anyhow::Result<Self>
-    where
-        R: Rng + Send,
-    {
-        Ok(Self::default())
-    }
-
     fn validate(&self, figment: &Figment) -> Result<(), figment::error::Error> {
         for (index, client) in self.0.iter().enumerate() {
             client.validate().map_err(|mut err| {
@@ -253,10 +250,6 @@ impl ConfigurationSection for ClientsConfig {
 
         Ok(())
     }
-
-    fn test() -> Self {
-        Self::default()
-    }
 }
 
 #[cfg(test)]

crates/config/src/sections/database.rs

@@ -14,9 +14,7 @@
 
 use std::{num::NonZeroU32, time::Duration};
 
-use async_trait::async_trait;
 use camino::Utf8PathBuf;
-use rand::Rng;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use serde_with::serde_as;
@@ -150,17 +148,9 @@ pub struct DatabaseConfig {
     pub max_lifetime: Option<Duration>,
 }
 
-#[async_trait]
 impl ConfigurationSection for DatabaseConfig {
     const PATH: Option<&'static str> = Some("database");
 
-    async fn generate<R>(_rng: R) -> anyhow::Result<Self>
-    where
-        R: Rng + Send,
-    {
-        Ok(Self::default())
-    }
-
     fn validate(&self, figment: &figment::Figment) -> Result<(), figment::error::Error> {
         let metadata = figment.find_metadata(Self::PATH.unwrap());
 
@@ -185,10 +175,6 @@ impl ConfigurationSection for DatabaseConfig {
 
         Ok(())
     }
-
-    fn test() -> Self {
-        Self::default()
-    }
 }
 
 #[cfg(test)]

crates/config/src/sections/email.rs

@@ -16,8 +16,6 @@
 
 use std::num::NonZeroU16;
 
-use async_trait::async_trait;
-use rand::Rng;
 use schemars::JsonSchema;
 use serde::{de::Error, Deserialize, Serialize};
 
@@ -181,17 +179,9 @@ impl Default for EmailConfig {
     }
 }
 
-#[async_trait]
 impl ConfigurationSection for EmailConfig {
     const PATH: Option<&'static str> = Some("email");
 
-    async fn generate<R>(_rng: R) -> anyhow::Result<Self>
-    where
-        R: Rng + Send,
-    {
-        Ok(Self::default())
-    }
-
     fn validate(&self, figment: &figment::Figment) -> Result<(), figment::error::Error> {
         let metadata = figment.find_metadata(Self::PATH.unwrap());
 
@@ -283,8 +273,4 @@ impl ConfigurationSection for EmailConfig {
 
         Ok(())
     }
-
-    fn test() -> Self {
-        Self::default()
-    }
 }

crates/config/src/sections/experimental.rs

@@ -12,9 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use async_trait::async_trait;
 use chrono::Duration;
-use rand::Rng;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use serde_with::serde_as;
@@ -25,6 +23,10 @@ fn default_token_ttl() -> Duration {
     Duration::microseconds(5 * 60 * 1000 * 1000)
 }
 
+fn is_default_token_ttl(value: &Duration) -> bool {
+    *value == default_token_ttl()
+}
+
 /// Configuration sections for experimental options
 ///
 /// Do not change these options unless you know what you are doing.
@@ -33,14 +35,20 @@ fn default_token_ttl() -> Duration {
 pub struct ExperimentalConfig {
     /// Time-to-live of access tokens in seconds. Defaults to 5 minutes.
     #[schemars(with = "u64", range(min = 60, max = 86400))]
-    #[serde(default = "default_token_ttl")]
+    #[serde(
+        default = "default_token_ttl",
+        skip_serializing_if = "is_default_token_ttl"
+    )]
     #[serde_as(as = "serde_with::DurationSeconds<i64>")]
     pub access_token_ttl: Duration,
 
     /// Time-to-live of compatibility access tokens in seconds. Defaults to 5
     /// minutes.
     #[schemars(with = "u64", range(min = 60, max = 86400))]
-    #[serde(default = "default_token_ttl")]
+    #[serde(
+        default = "default_token_ttl",
+        skip_serializing_if = "is_default_token_ttl"
+    )]
     #[serde_as(as = "serde_with::DurationSeconds<i64>")]
     pub compat_token_ttl: Duration,
 }
@@ -54,18 +62,12 @@ impl Default for ExperimentalConfig {
     }
 }
 
-#[async_trait]
-impl ConfigurationSection for ExperimentalConfig {
-    const PATH: Option<&'static str> = Some("experimental");
-
-    async fn generate<R>(_rng: R) -> anyhow::Result<Self>
-    where
-        R: Rng + Send,
-    {
-        Ok(Self::default())
+impl ExperimentalConfig {
+    pub(crate) fn is_default(&self) -> bool {
+        is_default_token_ttl(&self.access_token_ttl) && is_default_token_ttl(&self.compat_token_ttl)
     }
+}
 
-    fn test() -> Self {
-        Self::default()
-    }
+impl ConfigurationSection for ExperimentalConfig {
+    const PATH: Option<&'static str> = Some("experimental");
 }

crates/config/src/sections/http.rs

@@ -17,11 +17,9 @@
 use std::{borrow::Cow, io::Cursor};
 
 use anyhow::bail;
-use async_trait::async_trait;
 use camino::Utf8PathBuf;
 use ipnetwork::IpNetwork;
 use mas_keystore::PrivateKey;
-use rand::Rng;
 use rustls_pki_types::{CertificateDer, PrivateKeyDer, PrivatePkcs8KeyDer};
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
@@ -61,6 +59,10 @@ fn http_listener_assets_path_default() -> Utf8PathBuf {
     "./share/assets/".into()
 }
 
+fn is_default_http_listener_assets_path(value: &Utf8PathBuf) -> bool {
+    *value == http_listener_assets_path_default()
+}
+
 fn default_trusted_proxies() -> Vec<IpNetwork> {
     vec![
         IpNetwork::new([192, 128, 0, 0].into(), 16).unwrap(),
@@ -302,7 +304,10 @@ pub enum Resource {
     /// Static files
     Assets {
         /// Path to the directory to serve.
-        #[serde(default = "http_listener_assets_path_default")]
+        #[serde(
+            default = "http_listener_assets_path_default",
+            skip_serializing_if = "is_default_http_listener_assets_path"
+        )]
         #[schemars(with = "String")]
         path: Utf8PathBuf,
     },
@@ -356,6 +361,7 @@ pub struct HttpConfig {
     pub public_base: Url,
 
     /// OIDC issuer URL. Defaults to `public_base` if not set.
+    #[serde(skip_serializing_if = "Option::is_none")]
     pub issuer: Option<Url>,
 }
 
@@ -401,17 +407,9 @@ impl Default for HttpConfig {
     }
 }
 
-#[async_trait]
 impl ConfigurationSection for HttpConfig {
     const PATH: Option<&'static str> = Some("http");
 
-    async fn generate<R>(_rng: R) -> anyhow::Result<Self>
-    where
-        R: Rng + Send,
-    {
-        Ok(Self::default())
-    }
-
     fn validate(&self, figment: &figment::Figment) -> Result<(), figment::Error> {
         for (index, listener) in self.listeners.iter().enumerate() {
             let annotate = |mut error: figment::Error| {
@@ -473,8 +471,4 @@ impl ConfigurationSection for HttpConfig {
 
         Ok(())
     }
-
-    fn test() -> Self {
-        Self::default()
-    }
 }

crates/config/src/sections/matrix.rs

@@ -12,7 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use async_trait::async_trait;
 use rand::{
     distributions::{Alphanumeric, DistString},
     Rng,
@@ -48,22 +47,23 @@ pub struct MatrixConfig {
     pub endpoint: Url,
 }
 
-#[async_trait]
 impl ConfigurationSection for MatrixConfig {
     const PATH: Option<&'static str> = Some("matrix");
+}
 
-    async fn generate<R>(mut rng: R) -> anyhow::Result<Self>
+impl MatrixConfig {
+    pub(crate) fn generate<R>(mut rng: R) -> Self
     where
         R: Rng + Send,
     {
-        Ok(Self {
+        Self {
             homeserver: default_homeserver(),
             secret: Alphanumeric.sample_string(&mut rng, 32),
             endpoint: default_endpoint(),
-        })
+        }
     }
 
-    fn test() -> Self {
+    pub(crate) fn test() -> Self {
         Self {
             homeserver: default_homeserver(),
             secret: "test".to_owned(),