Instrument core code paths with tracing spans

Cargo.toml

@@ -29,6 +29,7 @@ thiserror = "1.0"
 time = { version = "0.3.5", features = ["serde"] }
 tokio = { version = "1.1", features = ["fs", "sync"] }
 tracing = "0.1.29"
+tracing-futures = "0.2.5"
 url = "2"
 which = "4.2"
 

src/authentication_manager.rs

@@ -42,6 +42,7 @@ impl AuthenticationManager {
     ///    if it succeeds, use the default service account as the token source.
     /// 4. Look for credentials in `.config/gcloud/application_default_credentials.json`;
     ///    if found, use these credentials to request refresh tokens.
+    #[tracing::instrument]
     pub async fn new() -> Result<Self, Error> {
         tracing::debug!("Initializing gcp_auth");
         if let Some(service_account) = CustomServiceAccount::from_env()? {

src/custom_service_account.rs

@@ -84,6 +84,7 @@ impl ServiceAccount for CustomServiceAccount {
         self.tokens.read().unwrap().get(&key).cloned()
     }
 
+    #[tracing::instrument]
     async fn refresh_token(&self, client: &HyperClient, scopes: &[&str]) -> Result<Token, Error> {
         use crate::jwt::Claims;
         use crate::jwt::GRANT_TYPE;

src/default_authorized_user.rs

@@ -35,6 +35,7 @@ impl DefaultAuthorizedUser {
             .unwrap()
     }
 
+    #[tracing::instrument]
     async fn get_token(client: &HyperClient) -> Result<Token, Error> {
         tracing::debug!("Loading user credentials file");
         let mut home = dirs_next::home_dir().ok_or(Error::NoHomeDir)?;

src/default_service_account.rs

@@ -34,6 +34,7 @@ impl DefaultServiceAccount {
             .unwrap()
     }
 
+    #[tracing::instrument]
     async fn get_token(client: &HyperClient) -> Result<Token, Error> {
         tracing::debug!("Getting token from GCP instance metadata server");
         let req = Self::build_token_request(Self::DEFAULT_TOKEN_GCP_URI);