chore: fix TestServer/Prometheus/DBMetricsDisabled test flake (#13453)

See: https://github.com/coder/coder/actions/runs/9352137263/job/25739550487#step:5:368

cli/server_test.go

@@ -967,8 +967,9 @@ func TestServer(t *testing.T) {
 				assert.NoError(t, err)
 				// nolint:bodyclose
 				res, err = http.DefaultClient.Do(req)
-				return err == nil
-			}, testutil.WaitShort, testutil.IntervalFast)
+				if err != nil {
+					return false
+				}
 				defer res.Body.Close()
 
 				scanner := bufio.NewScanner(res.Body)
@@ -985,8 +986,13 @@ func TestServer(t *testing.T) {
 					}
 					t.Logf("scanned %s", scanner.Text())
 				}
-			require.NoError(t, scanner.Err())
-			require.True(t, hasActiveUsers)
+				if scanner.Err() != nil {
+					t.Logf("scanner err: %s", scanner.Err().Error())
+					return false
+				}
+
+				return hasActiveUsers
+			}, testutil.WaitShort, testutil.IntervalFast, "didn't find coderd_api_active_users_duration_hour in time")
 		})
 
 		t.Run("DBMetricsEnabled", func(t *testing.T) {
@@ -1017,8 +1023,9 @@ func TestServer(t *testing.T) {
 				assert.NoError(t, err)
 				// nolint:bodyclose
 				res, err = http.DefaultClient.Do(req)
-				return err == nil
-			}, testutil.WaitShort, testutil.IntervalFast)
+				if err != nil {
+					return false
+				}
 				defer res.Body.Close()
 
 				scanner := bufio.NewScanner(res.Body)
@@ -1029,8 +1036,12 @@ func TestServer(t *testing.T) {
 					}
 					t.Logf("scanned %s", scanner.Text())
 				}
-			require.NoError(t, scanner.Err())
-			require.True(t, hasDBMetrics)
+				if scanner.Err() != nil {
+					t.Logf("scanner err: %s", scanner.Err().Error())
+					return false
+				}
+				return hasDBMetrics
+			}, testutil.WaitShort, testutil.IntervalFast, "didn't find coderd_db_query_latencies_seconds in time")
 		})
 	})
 	t.Run("GitHubOAuth", func(t *testing.T) {
@@ -1347,7 +1358,7 @@ func TestServer(t *testing.T) {
 			}
 			return lastStat.Size() > 0
 		},
-			testutil.WaitShort,
+			dur, //nolint:gocritic
 			testutil.IntervalFast,
 			"file at %s should exist, last stat: %+v",
 			fiName, lastStat,

coderd/prometheusmetrics/prometheusmetrics.go

@@ -120,9 +120,9 @@ func Workspaces(ctx context.Context, logger slog.Logger, registerer prometheus.R
 			if errors.Is(err, sql.ErrNoRows) {
 				// clear all series if there are no database entries
 				workspaceLatestBuildTotals.Reset()
-			}
-
+			} else {
 				logger.Warn(ctx, "failed to load latest workspace builds", slog.Error(err))
+			}
 			return
 		}
 		jobIDs := make([]uuid.UUID, 0, len(builds))