refactor(ops/yandex-cloud-rs): allow TokenProvider impls to fail r/6289

It's actually quite common that a token provider might fail, for
example when fetching a token from instance metadata.

Change-Id: Ie0126fb92c6c613ad36b5583fd68505fdd97f2c1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8764
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

1 files changed, 6 insertions, 6 deletions

diff --git a/ops/yandex-cloud-rs/src/lib.rs b/ops/yandex-cloud-rs/src/lib.rs
index 5e92f05417..87a9164e07 100644
--- a/ops/yandex-cloud-rs/src/lib.rs
+++ b/ops/yandex-cloud-rs/src/lib.rs
@@ -52,18 +52,18 @@ pub mod tonic_exports {
 /// tokens for Yandex Cloud.
 pub trait TokenProvider {
     /// Fetch a currently valid authentication token for Yandex Cloud.
-    fn get_token<'a>(&'a mut self) -> &'a str;
+    fn get_token<'a>(&'a mut self) -> Result<&'a str, tonic::Status>;
 }
 
 impl TokenProvider for String {
-    fn get_token<'a>(&'a mut self) -> &'a str {
-        self.as_str()
+    fn get_token<'a>(&'a mut self) -> Result<&'a str, tonic::Status> {
+        Ok(self.as_str())
     }
 }
 
 impl TokenProvider for &'static str {
-    fn get_token(&mut self) -> &'static str {
-        *self
+    fn get_token(&mut self) -> Result<&'static str, tonic::Status> {
+        Ok(*self)
     }
 }
 
@@ -89,7 +89,7 @@ impl<T: TokenProvider> Interceptor for AuthInterceptor<T> {
         &mut self,
         mut request: tonic::Request<()>,
     ) -> Result<tonic::Request<()>, tonic::Status> {
-        let token: MetadataValue<Ascii> = format!("Bearer {}", self.token_provider.get_token())
+        let token: MetadataValue<Ascii> = format!("Bearer {}", self.token_provider.get_token()?)
             .try_into()
             .map_err(|_| {
                 tonic::Status::invalid_argument("authorization token contained invalid characters")