fix: Use Debug trait formatter for API errors

This change will, instead of using the default Display formatter when
logging the API request's error, use the Debug trait's formatter
for a sanitized output.

The test include will confirm Debug display sanitizes API error.

In cases where there are errand special characters like newlines in
an API request's payload, this can result in deserialization errors.
These errors can result in noisy or "disjointed" logs, such as in the
case of newlines. Using the Debug `:?` trait's string formatter should
escape special characters.

Signed-off-by: Matthew Schlebusch <[email protected]>

Author: mattschlebusch

src/api_server/Cargo.toml

@@ -23,4 +23,4 @@ utils = { path = "../utils" }
 vmm = { path = "../vmm" }
 
 [dev-dependencies]
-libc = "0.2.117"
+libc = "0.2.117"

src/api_server/src/lib.rs

@@ -243,7 +243,7 @@ impl ApiServer {
                 response
             }
             Err(err) => {
-                error!("{}", err);
+                error!("{:?}", err);
                 err.into()
             }
         }
@@ -320,6 +320,29 @@ mod tests {
     use vmm::vmm_config::snapshot::CreateSnapshotParams;
 
     use super::*;
+    use crate::request::cpu_configuration::parse_put_cpu_config;
+
+    /// Test unescaped CPU template in JSON format.
+    /// Newlines injected into a field's value to
+    /// test deserialization and logging.
+    #[cfg(target_arch = "x86_64")]
+    const TEST_UNESCAPED_JSON_TEMPLATE: &str = r#"{
+      "msr_modifiers": [
+        {
+          "addr": "0x0\n\n\n\nTEST\n\n\n\n",
+          "bitmap": "0b00"
+        }
+      ]
+    }"#;
+    #[cfg(target_arch = "aarch64")]
+    pub const TEST_UNESCAPED_JSON_TEMPLATE: &str = r#"{
+      "reg_modifiers": [
+        {
+          "addr": "0x0\n\n\n\nTEST\n\n\n\n",
+          "bitmap": "0b00"
+        }
+      ]
+    }"#;
 
     #[test]
     fn test_serve_vmm_action_request() {
@@ -433,6 +456,30 @@ mod tests {
         assert_eq!(response.status(), StatusCode::BadRequest);
     }
 
+    #[test]
+    fn test_handle_request_logging() {
+        let cpu_template_json = TEST_UNESCAPED_JSON_TEMPLATE;
+        let result = parse_put_cpu_config(&Body::new(cpu_template_json.as_bytes()));
+        assert!(result.is_err());
+        let result_error = result.unwrap_err();
+        let err_msg = format!("{}", result_error);
+        assert_ne!(
+            1,
+            err_msg.lines().count(),
+            "Error Body response:\n{}",
+            err_msg
+        );
+
+        let err_msg_with_debug = format!("{:?}", result_error);
+        // Check the loglines are on one line.
+        assert_eq!(
+            1,
+            err_msg_with_debug.lines().count(),
+            "Error Body response:\n{}",
+            err_msg_with_debug
+        );
+    }
+
     #[test]
     fn test_bind_and_run() {
         let mut tmp_socket = TempFile::new().unwrap();