Update metrics on deploy key usage (#35518)

We eventually want to fully deprecate legacy deploy keys. This metric previously grouped together system keys (which other Convex services use to talk to backends) with the legacy keys, so now these are split out.

GitOrigin-RevId: 138866704b6a74e74578d1dadc3a01d24b6f25fa

Author: sshader

crates/authentication/src/application_auth.rs

@@ -40,13 +40,25 @@ impl ApplicationAuth {
             .is_encrypted_admin_key(&admin_key_or_access_token)
         {
             // assume this is a legacy Deploy Key
-            log_deploy_key_use(DeployKeyType::Legacy);
-            self.key_broker
+            let result = self
+                .key_broker
                 .check_admin_key(&admin_key_or_access_token)
                 .context(ErrorMetadata::unauthenticated(
                     "BadAdminKey",
                     "The provided admin key was invalid for this instance",
-                ))
+                ));
+            match &result {
+                Ok(Identity::InstanceAdmin(_)) => {
+                    log_deploy_key_use(DeployKeyType::Legacy);
+                },
+                Ok(Identity::System(_)) => {
+                    log_deploy_key_use(DeployKeyType::System);
+                },
+                _ => {
+                    log_deploy_key_use(DeployKeyType::Unknown);
+                },
+            }
+            result
         } else {
             // assume this is an Access Token
             // Access Tokens are base64 encoded strings

crates/authentication/src/metrics.rs

@@ -8,13 +8,17 @@ register_convex_counter!(pub DEPLOY_KEY_USE_TOTAL, "Count of deploy key uses", &
 
 pub enum DeployKeyType {
     Legacy,
+    System,
+    Unknown,
     AccessToken,
 }
 
 pub fn log_deploy_key_use(key_type: DeployKeyType) {
     let key_type_label = match key_type {
         DeployKeyType::Legacy => "legacy",
+        DeployKeyType::System => "system",
         DeployKeyType::AccessToken => "access_token",
+        DeployKeyType::Unknown => "unknown",
     };
     log_counter_with_labels(
         &DEPLOY_KEY_USE_TOTAL,