Fix error in FindRequest.NumVersions handling

metadb/server/service.go

@@ -3,6 +3,7 @@ package server
 import (
 	"context"
 	"database/sql"
+	"fmt"
 	"log"
 	"path/filepath"
 	"strings"
@@ -64,6 +65,11 @@ func (a *dbAtom) getAtom() tabacco.Atom {
 }
 
 func normalizeAtoms(dbAtoms []dbAtom, numVersions int) [][]tabacco.Version {
+	// numVersions == 0 is remapped to 1.
+	if numVersions < 1 {
+		numVersions = 1
+	}
+
 	// Accumulate versions keyed by backup ID first, dataset name
 	// next. Preserve the ordering of backups in dbAtoms, which we
 	// are going to use later to apply a per-dataset limit.
@@ -104,11 +110,10 @@ func normalizeAtoms(dbAtoms []dbAtom, numVersions int) [][]tabacco.Version {
 		backup := backupMap[backupID]
 		var tmpv []tabacco.Version
 		for _, ds := range tmp {
-			if dsCount[ds.Name] >= numVersions {
-				continue
+			if dsCount[ds.Name] < numVersions {
+				tmpv = append(tmpv, tabacco.Version{Backup: *backup, Dataset: *ds})
+				dsCount[ds.Name]++
 			}
-			tmpv = append(tmpv, tabacco.Version{Backup: *backup, Dataset: *ds})
-			dsCount[ds.Name]++
 		}
 		if len(tmpv) > 0 {
 			out = append(out, tmpv)
@@ -193,6 +198,8 @@ func (s *Service) FindAtoms(ctx context.Context, req tabacco.FindRequest) ([][]t
 	}
 	defer tx.Rollback() // nolint
 
+	// Build the SQL query. Assemble the WHERE clauses and their
+	// respective arguments first.
 	var where []string
 	var args []interface{}
 	if req.Host != "" {
@@ -204,11 +211,16 @@ func (s *Service) FindAtoms(ctx context.Context, req tabacco.FindRequest) ([][]t
 		args = append(args, strings.Replace(req.Pattern, "*", "%", -1))
 	}
 
-	q := `  SELECT 
-		  backup_id, backup_timestamp, backup_host,
-		  dataset_name, dataset_handler,
-		  atom_name, atom_path, atom_source_path, atom_relative_path
-		FROM log WHERE ` + strings.Join(where, " AND ")
+	// Build the final query and execute it.
+	q := fmt.Sprintf(
+		`SELECT 
+		   backup_id, backup_timestamp, backup_host,
+		   dataset_name, dataset_handler,
+		   atom_name, atom_path, atom_source_path, atom_relative_path
+		 FROM log WHERE %s
+                 ORDER BY backup_timestamp DESC`,
+		strings.Join(where, " AND "),
+	)
 	rows, err := tx.Query(q, args...)
 	if err != nil {
 		return nil, err

metadb/server/service_test.go

@@ -69,7 +69,8 @@ func TestService_FindAtoms(t *testing.T) {
 	vv, err := svc.FindAtoms(
 		context.Background(),
 		tabacco.FindRequest{
-			Pattern: "*/sub1",
+			Pattern:     "*/sub1",
+			NumVersions: 10,
 		},
 	)
 	if err != nil {