Add exptime support for virtual xattrs

Author: bbrks

collection+xattrs.go

@@ -27,6 +27,7 @@ const (
 	virtualXattrName     = "$document"
 	virtualXattrRevSeqNo = "revid"
 	virtualXattrCAS      = "CAS"
+	virtualXattrExpiry   = "exptime"
 )
 
 // ////// SGBUCKET XATTR STORE INTERFACE
@@ -412,12 +413,13 @@ func (c *Collection) getRawXattrs(txn *sql.Tx, key string) ([]byte, error) {
 // get doc's raw body and an xattr.
 func (c *Collection) getRawWithXattrs(key string, xattrKeys []string) (sgbucket.BucketDocument, error) {
 	var revSeqNo int64
-	row := c.db().QueryRow(`SELECT value, cas, xattrs, tombstone, revSeqNo FROM documents WHERE collection=?1 AND key=?2`, c.id, key)
+	var exp Exp
+	row := c.db().QueryRow(`SELECT value, cas, xattrs, tombstone, revSeqNo, exp FROM documents WHERE collection=?1 AND key=?2`, c.id, key)
 	rawDoc := sgbucket.BucketDocument{
 		Xattrs: make(map[string][]byte, len(xattrKeys)),
 	}
 	var xattrs []byte
-	err := scan(row, &rawDoc.Body, &rawDoc.Cas, &xattrs, &rawDoc.IsTombstone, &revSeqNo)
+	err := scan(row, &rawDoc.Body, &rawDoc.Cas, &xattrs, &rawDoc.IsTombstone, &revSeqNo, &exp)
 	if err != nil {
 		return sgbucket.BucketDocument{}, remapKeyError(err, key)
 	}
@@ -438,6 +440,9 @@ func (c *Collection) getRawWithXattrs(key string, xattrKeys []string) (sgbucket.
 		} else if xattrKey == virtualXattrName+"."+virtualXattrCAS {
 			rawDoc.Xattrs[xattrKey] = []byte(fmt.Sprintf(`"0x%s"`, strconv.FormatUint(rawDoc.Cas, 16)))
 			continue
+		} else if xattrKey == virtualXattrName+"."+virtualXattrExpiry {
+			rawDoc.Xattrs[xattrKey] = []byte(strconv.FormatUint(uint64(exp), 10))
+			continue
 		}
 		val, ok := xattrMap[xattrKey]
 		if !ok {

collection_test.go

@@ -1088,6 +1088,30 @@ func TestVirtualXattr(t *testing.T) {
 		expectedCAS := fmt.Sprintf(`0x%s`, strconv.FormatUint(cas, 16))
 		require.Equal(t, expectedCAS, fetchedCAS)
 	})
+
+	// $document.exptime returns the doc expiry as a JSON number (always present, even when 0).
+	t.Run("expiry", func(t *testing.T) {
+		xattrKey := fmt.Sprintf("%s.%s", virtualXattrName, virtualXattrExpiry)
+
+		// Doc written above has no expiry — should return 0.
+		xattrs, _, err := col.GetXattrs(ctx, docID, []string{xattrKey})
+		require.NoError(t, err)
+		require.Contains(t, xattrs, xattrKey)
+		var fetchedExpiry uint32
+		require.NoError(t, json.Unmarshal(xattrs[xattrKey], &fetchedExpiry))
+		require.Equal(t, uint32(0), fetchedExpiry)
+
+		// Write a doc with a real expiry and confirm it round-trips.
+		expDocID := docID + "_exp"
+		expiry := uint32(time.Now().Add(1 * time.Hour).Unix())
+		require.NoError(t, col.Set(ctx, expDocID, expiry, nil, []byte(`{"foo": 2}`)))
+
+		xattrs, _, err = col.GetXattrs(ctx, expDocID, []string{xattrKey})
+		require.NoError(t, err)
+		require.Contains(t, xattrs, xattrKey)
+		require.NoError(t, json.Unmarshal(xattrs[xattrKey], &fetchedExpiry))
+		require.Equal(t, expiry, fetchedExpiry)
+	})
 }
 
 func assertRevSeqNo(t *testing.T, col *Collection, docID string, expectedRevSeqNo string) {