[Configs] Fix config env overrides

Given that `list_separator` is called, the `config` crate expects every key to be a list unless `with_list_parse_key` is called which defines the list of keys that are supposed to be vectors. This diff lets each service define which of its keys are vector and pass it during service config registration.

cronback-lib/config.rs

@@ -66,6 +66,7 @@ pub struct ConfigBuilder {
     builder: InnerBuilder<DefaultState>,
     file_sources: Vec<PathBuf>,
     section_loaders: SectionLoaders,
+    array_keys: HashSet<String>,
 }
 
 impl ConfigBuilder {
@@ -78,6 +79,7 @@ impl ConfigBuilder {
             builder,
             file_sources: Vec::default(),
             section_loaders: HashMap::default(),
+            array_keys: HashSet::default(),
         };
         // Register main section loader by default.
         loader = loader.register_section_loader::<MainConfig>("main");
@@ -104,10 +106,11 @@ impl ConfigBuilder {
         }
     }
 
-    pub fn register_service<S>(self) -> Self
+    pub fn register_service<S>(mut self) -> Self
     where
         S: CronbackService,
     {
+        self.array_keys.extend(S::config_vec_keys());
         self.add_default_toml(S::DEFAULT_CONFIG_TOML)
             .register_section_loader::<<S as CronbackService>::ServiceConfig>(
             S::CONFIG_SECTION,
@@ -117,12 +120,14 @@ impl ConfigBuilder {
     // This needs to be the last source added to the builder to ensure that
     // environemnt variables are not overridden by files or default config.
     fn add_env_source(mut self) -> Self {
-        self.builder = self.builder.add_source(
-            Environment::with_prefix(&self.env_prefix)
-                .try_parsing(true)
-                .separator("__")
-                .list_separator(","),
-        );
+        let mut env = Environment::with_prefix(&self.env_prefix)
+            .try_parsing(true)
+            .separator("__")
+            .list_separator(",");
+        for key in &self.array_keys {
+            env = env.with_list_parse_key(key);
+        }
+        self.builder = self.builder.add_source(env);
         self
     }
 

cronback-lib/service.rs

@@ -1,3 +1,4 @@
+use std::collections::HashSet;
 use std::convert::Infallible;
 use std::error::Error;
 use std::net::SocketAddr;
@@ -59,6 +60,12 @@ pub trait CronbackService: Send + Sync + Sized + Clone + 'static {
         ServiceContext::new(config, shutdown)
     }
 
+    // The list of keys in this service configs that should be parsed
+    // as vectors.
+    fn config_vec_keys() -> HashSet<String> {
+        HashSet::default()
+    }
+
     /// Optional hook to install telemetry for the service.
     fn install_telemetry() {}
 

cronback-services/src/api/mod.rs

@@ -11,6 +11,7 @@ mod logging;
 mod migration;
 mod paginated;
 
+use std::collections::HashSet;
 use std::net::SocketAddr;
 use std::sync::Arc;
 use std::time::Instant;
@@ -73,6 +74,12 @@ impl CronbackService for ApiService {
         );
     }
 
+    fn config_vec_keys() -> HashSet<String> {
+        let mut set = HashSet::new();
+        set.insert("api.admin_api_keys".to_string());
+        set
+    }
+
     #[tracing::instrument(skip_all, fields(service = context.service_name()))]
     async fn serve(
         mut context: ServiceContext<Self>,