storage: log /uploads SQL queries

Change-Id: I0aad9567cc8887922541145868fd927d8c4fb10b
Reviewed-on: https://go-review.googlesource.com/37167
Run-TryBot: Quentin Smith <quentin@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

storage/app/query.go

@@ -76,6 +76,8 @@ func (a *App) uploads(w http.ResponseWriter, r *http.Request) {
 	res := a.DB.ListUploads(q, r.Form["extra_label"], limit)
 	defer res.Close()
 
+	infof(ctx, "query: %s", res.Debug())
+
 	w.Header().Set("Content-Type", "application/json")
 	e := json.NewEncoder(w)
 	for res.Next() {

storage/db/db.go

@@ -554,6 +554,10 @@ func (db *DB) Close() error {
 type UploadList struct {
 	rows        *sql.Rows
 	extraLabels []string
+	// for Debug
+	q        string
+	sqlQuery string
+	sqlArgs  []interface{}
 	// from last call to Next
 	count       int
 	uploadID    string
@@ -561,11 +565,25 @@ type UploadList struct {
 	err         error
 }
 
+// Debug returns the human-readable state of ul.
+func (ul *UploadList) Debug() string {
+	ret := fmt.Sprintf("q=%q", ul.q)
+	if ul.sqlQuery != "" || len(ul.sqlArgs) > 0 {
+		ret += fmt.Sprintf(" sql={%q %#v}", ul.sqlQuery, ul.sqlArgs)
+	}
+	if ul.err != nil {
+		ret += fmt.Sprintf(" err=%v", ul.err)
+	}
+	return ret
+}
+
 // ListUploads searches for uploads containing results matching the given query string.
 // The query may be empty, in which case all uploads will be returned.
 // For each label in extraLabels, one unspecified record's value will be obtained for each upload.
 // If limit is non-zero, only the limit most recent uploads will be returned.
 func (db *DB) ListUploads(q string, extraLabels []string, limit int) *UploadList {
+	ret := &UploadList{q: q, extraLabels: extraLabels}
+
 	var args []interface{}
 	query := "SELECT j.UploadID, rCount"
 	for i, label := range extraLabels {
@@ -575,7 +593,8 @@ func (db *DB) ListUploads(q string, extraLabels []string, limit int) *UploadList
 	query += " FROM (SELECT UploadID, COUNT(*) as rCount FROM "
 	sql, qArgs, err := parseQuery(q)
 	if err != nil {
-		return &UploadList{err: err}
+		ret.err = err
+		return ret
 	}
 	args = append(args, qArgs...)
 	for i, part := range sql {
@@ -600,11 +619,9 @@ func (db *DB) ListUploads(q string, extraLabels []string, limit int) *UploadList
 		query += fmt.Sprintf(" LIMIT %d", limit)
 	}
 
-	rows, err := db.sql.Query(query, args...)
-	if err != nil {
-		return &UploadList{err: err}
-	}
-	return &UploadList{rows: rows, extraLabels: extraLabels}
+	ret.sqlQuery, ret.sqlArgs = query, args
+	ret.rows, ret.err = db.sql.Query(query, args...)
+	return ret
 }
 
 // Next prepares the next result for reading with the Result