From 683df3e58cbd56bd64fd88ed28bd0e8cbaa3c578 Mon Sep 17 00:00:00 2001
From: David Crespo <david.crespo@oxidecomputer.com>
Date: Tue, 3 Dec 2024 14:43:30 -0600
Subject: [PATCH] extract error map logic to helper for reasons of cuteness

---
 nexus/src/app/metrics.rs | 58 +++++++++++++++-------------------------
 1 file changed, 22 insertions(+), 36 deletions(-)

diff --git a/nexus/src/app/metrics.rs b/nexus/src/app/metrics.rs
index 7f2bd8c1e0..5b77e681b1 100644
--- a/nexus/src/app/metrics.rs
+++ b/nexus/src/app/metrics.rs
@@ -140,29 +140,15 @@ impl super::Nexus {
         self.timeseries_client
             .oxql_query(query)
             .await
-            .map(|result| {
-                // TODO-observability: The query method returns information
-                // about the duration of the OxQL query and the database
-                // resource usage for each contained SQL query. We should
-                // publish this as a timeseries itself, so that we can track
-                // improvements to query processing.
-                //
-                // For now, simply return the tables alone.
-                result.tables
-            })
-            .map_err(|e| match e {
-                oximeter_db::Error::DatabaseUnavailable(_)
-                | oximeter_db::Error::Connection(_) => {
-                    Error::ServiceUnavailable {
-                        internal_message: e.to_string(),
-                    }
-                }
-                oximeter_db::Error::Oxql(_)
-                | oximeter_db::Error::TimeseriesNotFound(_) => {
-                    Error::invalid_request(e.to_string())
-                }
-                _ => Error::InternalError { internal_message: e.to_string() },
-            })
+            // TODO-observability: The query method returns information
+            // about the duration of the OxQL query and the database
+            // resource usage for each contained SQL query. We should
+            // publish this as a timeseries itself, so that we can track
+            // improvements to query processing.
+            //
+            // For now, simply return the tables alone.
+            .map(|result| result.tables)
+            .map_err(map_timeseries_err)
     }
 
     /// Run an OxQL query against the timeseries database, scoped to a specific project.
@@ -188,18 +174,18 @@ impl super::Nexus {
             .oxql_query(filtered_query)
             .await
             .map(|result| result.tables)
-            .map_err(|e| match e {
-                oximeter_db::Error::DatabaseUnavailable(_)
-                | oximeter_db::Error::Connection(_) => {
-                    Error::ServiceUnavailable {
-                        internal_message: e.to_string(),
-                    }
-                }
-                oximeter_db::Error::Oxql(_)
-                | oximeter_db::Error::TimeseriesNotFound(_) => {
-                    Error::invalid_request(e.to_string())
-                }
-                _ => Error::InternalError { internal_message: e.to_string() },
-            })
+            .map_err(map_timeseries_err)
+    }
+}
+
+fn map_timeseries_err(e: oximeter_db::Error) -> Error {
+    match e {
+        oximeter_db::Error::DatabaseUnavailable(_)
+        | oximeter_db::Error::Connection(_) => Error::unavail(&e.to_string()),
+        oximeter_db::Error::Oxql(_)
+        | oximeter_db::Error::TimeseriesNotFound(_) => {
+            Error::invalid_request(e.to_string())
+        }
+        _ => Error::internal_error(&e.to_string()),
     }
 }