Feat: Add api_token field to client configuration (#514)

* Add api_token field to client configuration for reading API tokens from env vars

Signed-off-by: Rob Geada <[email protected]>

* Move env var read to deserialization

Signed-off-by: Rob Geada <[email protected]>

---------

Signed-off-by: Rob Geada <[email protected]>

Author: RobGeada

src/clients.rs

@@ -254,7 +254,11 @@ pub async fn create_http_client(
         .layer(http_trace_layer())
         .layer(TimeoutLayer::new(request_timeout))
         .service(client);
-    Ok(HttpClient::new(base_url, client))
+    Ok(HttpClient::new(
+        base_url,
+        service_config.api_token.clone(),
+        client,
+    ))
 }
 
 pub async fn create_grpc_client<C: Debug + Clone>(

src/clients/http.rs

@@ -119,15 +119,17 @@ pub trait HttpClientExt: Client {
 pub struct HttpClient {
     base_url: Url,
     health_url: Url,
+    api_token: Option<String>,
     inner: HttpClientInner,
 }
 
 impl HttpClient {
-    pub fn new(base_url: Url, inner: HttpClientInner) -> Self {
+    pub fn new(base_url: Url, api_token: Option<String>, inner: HttpClientInner) -> Self {
         let health_url = base_url.join("health").unwrap();
         Self {
             base_url,
             health_url,
+            api_token,
             inner,
         }
     }
@@ -140,6 +142,19 @@ impl HttpClient {
         self.base_url.join(path).unwrap()
     }
 
+    /// Injects the API token as a Bearer token in the Authorization header if configured and present in the environment.
+    fn inject_api_token(&self, headers: &mut HeaderMap) -> Result<(), Error> {
+        if let Some(token) = &self.api_token {
+            headers.insert(
+                http::header::AUTHORIZATION,
+                HeaderValue::from_str(&format!("Bearer {}", token)).map_err(|e| Error::Http {
+                    code: StatusCode::INTERNAL_SERVER_ERROR,
+                    message: format!("invalid authorization header: {e}"),
+                })?,
+            );
+        }
+        Ok(())
+    }
     pub async fn get(
         &self,
         url: Url,
@@ -162,11 +177,14 @@ impl HttpClient {
         &self,
         url: Url,
         method: Method,
-        headers: HeaderMap,
+        mut headers: HeaderMap,
         body: impl RequestBody,
     ) -> Result<Response, Error> {
         let ctx = Span::current().context();
+
+        self.inject_api_token(&mut headers)?;
         let headers = trace::with_traceparent_header(&ctx, headers);
+
         let mut builder = hyper::http::request::Builder::new()
             .method(method)
             .uri(url.as_uri());

src/config.rs

@@ -23,7 +23,10 @@ use std::{
 use serde::Deserialize;
 use tracing::{debug, error, info, warn};
 
-use crate::clients::{chunker::DEFAULT_CHUNKER_ID, is_valid_hostname};
+use crate::{
+    clients::{chunker::DEFAULT_CHUNKER_ID, is_valid_hostname},
+    utils::from_env,
+};
 
 /// Default allowed headers to passthrough to clients.
 const DEFAULT_ALLOWED_HEADERS: &[&str] = &[];
@@ -86,6 +89,9 @@ pub struct ServiceConfig {
     pub http2_keep_alive_interval: Option<u64>,
     /// Keep-alive timeout in seconds for client calls [currently only for grpc generation]
     pub keep_alive_timeout: Option<u64>,
+    /// Name of environment variable that contains the API key to use for this service [currently only for http generation]
+    #[serde(default, deserialize_with = "from_env")]
+    pub api_token: Option<String>,
 }
 
 impl ServiceConfig {
@@ -101,6 +107,7 @@ impl ServiceConfig {
             max_retries: None,
             http2_keep_alive_interval: None,
             keep_alive_timeout: None,
+            api_token: None,
         }
     }
 }

src/utils.rs

@@ -34,3 +34,56 @@ where
         OneOrMany::Many(values) => Ok(values),
     }
 }
+
+/// Serde helper to deserialize value from environment variable.
+pub fn from_env<'de, D>(deserializer: D) -> Result<Option<String>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let env_name: Option<String> = Option::deserialize(deserializer)?;
+    if let Some(env_name) = env_name {
+        let value = std::env::var(&env_name)
+            .map_err(|_| serde::de::Error::custom(format!("env var `{env_name}` not found")))?;
+        Ok(Some(value))
+    } else {
+        Ok(None)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use serde::Deserialize;
+    use serde_json::json;
+
+    use super::from_env;
+
+    #[derive(Debug, Deserialize)]
+    pub struct Config {
+        #[serde(default, deserialize_with = "from_env")]
+        pub api_token: Option<String>,
+    }
+
+    #[test]
+    fn test_from_env() -> Result<(), Box<dyn std::error::Error>> {
+        // Test no value
+        let config: Config = serde_json::from_value(json!({}))?;
+        assert_eq!(config.api_token, None);
+
+        // Test invalid value
+        let config: Result<Config, serde_json::error::Error> = serde_json::from_value(json!({
+            "api_token": "DOES_NOT_EXIST"
+        }));
+        assert!(config.is_err_and(|err| err.to_string() == "env var `DOES_NOT_EXIST` not found"));
+
+        // Test valid value
+        unsafe {
+            std::env::set_var("CLIENT_API_TOKEN", "token");
+        }
+        let config: Config = serde_json::from_value(json!({
+            "api_token": "CLIENT_API_TOKEN"
+        }))?;
+        assert_eq!(config.api_token, Some("token".into()));
+
+        Ok(())
+    }
+}