From 3d59b342b0a648f03942d1d6f96660c5e78c7ca1 Mon Sep 17 00:00:00 2001
From: Stephen Soltesz <soltesz@google.com>
Date: Mon, 22 Mar 2021 17:31:56 +0000
Subject: [PATCH] Propagate registration error (#34)

---
 internal/setup/setup.go | 6 +++---
 sql/collector.go        | 4 ++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/internal/setup/setup.go b/internal/setup/setup.go
index 72a0b8a..cdec817 100644
--- a/internal/setup/setup.go
+++ b/internal/setup/setup.go
@@ -55,7 +55,7 @@ func (f *File) Register(c *sql.Collector) error {
 		logx.Debug.Println("Unregister:", ok)
 		if !ok {
 			// This is a fatal error. If the
-			return fmt.Errorf("Failed to unregister %q", f.Name)
+			return fmt.Errorf("failed to unregister %q", f.Name)
 		}
 		f.c = nil
 	}
@@ -65,10 +65,10 @@ func (f *File) Register(c *sql.Collector) error {
 		// While collector Update could fail transiently, this may be a fatal error.
 		return err
 	}
-	logx.Debug.Println("Register: success:", f.Name)
+	logx.Debug.Println("Register:", f.Name, c.RegisterErr)
 	// Save the registered collector.
 	f.c = c
-	return nil
+	return c.RegisterErr
 }
 
 // Update runs the collector query again.
diff --git a/sql/collector.go b/sql/collector.go
index fe1f127..3f01188 100644
--- a/sql/collector.go
+++ b/sql/collector.go
@@ -51,6 +51,9 @@ type Collector struct {
 	metrics []Metric
 	// mux locks access to types above.
 	mux sync.Mutex
+
+	// RegisterErr contains any error during registration. This should be considered fatal.
+	RegisterErr error
 }
 
 // NewCollector creates a new BigQuery Collector instance.
@@ -76,6 +79,7 @@ func (col *Collector) Describe(ch chan<- *prometheus.Desc) {
 		err := col.Update()
 		if err != nil {
 			log.Println(err)
+			col.RegisterErr = err
 		}
 		col.setDesc()
 	}