Make telemetry configurable

Also allows opting-out of the OTLP exporter to remove the dependency to
protoc when building.

crates/config/src/lib.rs

@@ -21,6 +21,7 @@ mod csrf;
 mod database;
 mod http;
 mod oauth2;
+mod telemetry;
 mod templates;
 mod util;
 
@@ -30,6 +31,7 @@ pub use self::{
     database::DatabaseConfig,
     http::HttpConfig,
     oauth2::{Algorithm, KeySet, OAuth2ClientConfig, OAuth2Config},
+    telemetry::{MetricsConfig, TelemetryConfig, TracingConfig},
     templates::TemplatesConfig,
     util::ConfigurationSection,
 };
@@ -46,6 +48,9 @@ pub struct RootConfig {
 
     pub cookies: CookiesConfig,
 
+    #[serde(default)]
+    pub telemetry: TelemetryConfig,
+
     #[serde(default)]
     pub templates: TemplatesConfig,
 
@@ -65,6 +70,7 @@ impl ConfigurationSection<'_> for RootConfig {
             http: HttpConfig::generate().await?,
             database: DatabaseConfig::generate().await?,
             cookies: CookiesConfig::generate().await?,
+            telemetry: TelemetryConfig::generate().await?,
             templates: TemplatesConfig::generate().await?,
             csrf: CsrfConfig::generate().await?,
         })
@@ -76,6 +82,7 @@ impl ConfigurationSection<'_> for RootConfig {
             http: HttpConfig::test(),
             database: DatabaseConfig::test(),
             cookies: CookiesConfig::test(),
+            telemetry: TelemetryConfig::test(),
             templates: TemplatesConfig::test(),
             csrf: CsrfConfig::test(),
         }