Fix #333 Add debug log if load_via_assume_role_with_web_identity is m…

…issing some value

src/tencent/credential.rs

@@ -115,7 +115,18 @@ impl CredentialLoader {
             (Some(region), Some(token_file), Some(role_arn), Some(provider_id)) => {
                 (region, token_file, role_arn, provider_id)
             }
-            _ => return Ok(None),
+            _ => {
+                debug!(
+                    "assume_role_with_web_identity is not configured fully, region: {region:?}, \
+                     web_identity_token_file: {token_file:?}, role_arn: {role_arn:?}, provider_id: {provider_id:?}",
+                    region = &self.config.region,
+                    token_file = &self.config.web_identity_token_file,
+                    role_arn = &self.config.role_arn,
+                    provider_id = &self.config.provider_id,
+                );
+
+                return Ok(None);
+            }
         };
 
         let token = fs::read_to_string(token_file)?;
@@ -210,10 +221,13 @@ struct AssumeRoleWithWebIdentityError {
 #[cfg(test)]
 mod tests {
     use std::env;
+    use std::fs::File;
+    use std::io::Read;
     use std::str::FromStr;
 
+    use env_logger::Target;
     use http::{Request, StatusCode};
-    use log::debug;
+    use log::{debug, LevelFilter};
     use once_cell::sync::Lazy;
     use tokio::runtime::Runtime;
 
@@ -347,4 +361,44 @@ mod tests {
 
         Ok(())
     }
+
+    #[tokio::test]
+    async fn test_assume_role_with_web_identity_none() {
+        let _ = fs::remove_file("test_reqwest.log");
+
+        let logfile = File::create("test_reqwest.log").expect("create log file failed");
+        let _ = env_logger::builder()
+            .target(Target::Pipe(Box::new(logfile)))
+            .filter_level(LevelFilter::Debug)
+            .is_test(true)
+            .try_init();
+
+        let config = Config {
+            region: Some("region".to_string()),
+            web_identity_token_file: None, // None web_identity_token_file
+            role_arn: Some("role".to_string()),
+            provider_id: None, // None provider_id
+            ..Default::default()
+        };
+        let loader = CredentialLoader::new(reqwest::Client::new(), config);
+        let cred = loader
+            .load_via_assume_role_with_web_identity()
+            .await
+            .expect("should load credential");
+
+        assert!(cred.is_none());
+
+        // test logfile content
+        let mut logfile = File::open("test_reqwest.log").expect("open log file");
+        let mut content = String::new();
+        logfile.read_to_string(&mut content).expect("read log file");
+
+        assert!(content.contains("region: Some(\"region\")"));
+        assert!(content.contains("web_identity_token_file: None"));
+        assert!(content.contains("role_arn: Some(\"role\")"));
+        assert!(content.contains("provider_id: None"));
+
+        // delete log file
+        fs::remove_file("test_reqwest.log").expect("remove log file");
+    }
 }