Add "append" modifier for "outfile" keyword to the mapreduce language

4 files changed, 72 insertions, 11 deletions

diff --git a/doc/querylanguage.md b/doc/querylanguage.md
index 41e95de..c3e567e 100644
--- a/doc/querylanguage.md
+++ b/doc/querylanguage.md
@@ -35,7 +35,7 @@ QUERY := select SELECT1[,SELECT2...]
          [set SET1,[,SET2...]]
          [interval NUMBER]
          [limit NUMBER]
-         [outfile STRING]
+         [outfile [append] STRING]
          [logformat LOGFORMAT]
 ```
 
diff --git a/internal/mapr/groupsetresult.go b/internal/mapr/groupsetresult.go
index 6d0ac1f..915b342 100644
--- a/internal/mapr/groupsetresult.go
+++ b/internal/mapr/groupsetresult.go
@@ -159,7 +159,7 @@ func (g *GroupSet) resultWriteFormattedDataEntry(query *Query, sb *strings.Build
 }
 
 func (*GroupSet) writeQueryFile(query *Query) error {
-	queryFile := fmt.Sprintf("%s.query", query.Outfile)
+	queryFile := fmt.Sprintf("%s.query", query.Outfile.FilePath)
 	tmpQueryFile := fmt.Sprintf("%s.tmp", queryFile)
 	dlog.Common.Debug("Writing query file", queryFile)
 
@@ -187,8 +187,8 @@ func (g *GroupSet) WriteResult(query *Query) error {
 		return err
 	}
 
-	dlog.Common.Info("Writing outfile", query.Outfile)
-	tmpOutfile := fmt.Sprintf("%s.tmp", query.Outfile)
+	dlog.Common.Info("Writing outfile", query.Outfile.FilePath)
+	tmpOutfile := fmt.Sprintf("%s.tmp", query.Outfile.FilePath)
 
 	fd, err := os.Create(tmpOutfile)
 	if err != nil {
@@ -228,7 +228,7 @@ func (g *GroupSet) resultWriteUnformatted(query *Query, rows []result, tmpOutfil
 		fd.WriteString("\n")
 	}
 
-	if err := os.Rename(tmpOutfile, query.Outfile); err != nil {
+	if err := os.Rename(tmpOutfile, query.Outfile.FilePath); err != nil {
 		os.Remove(tmpOutfile)
 		return err
 	}
diff --git a/internal/mapr/query.go b/internal/mapr/query.go
index d70675f..4eeb7b6 100644
--- a/internal/mapr/query.go
+++ b/internal/mapr/query.go
@@ -13,6 +13,15 @@ const (
 	unexpectedEnd string = "Unexpected end of query"
 )
 
+type Outfile struct {
+	FilePath   string
+	AppendMode bool
+}
+
+func (o Outfile) String() string {
+	return fmt.Sprintf("Outfile(FilePath:%v,AppendMode:%v)", o.FilePath, o.AppendMode)
+}
+
 // Query represents a parsed mapr query.
 type Query struct {
 	Select       []selectCondition
@@ -25,7 +34,7 @@ type Query struct {
 	GroupKey     string
 	Interval     time.Duration
 	Limit        int
-	Outfile      string
+	Outfile      *Outfile
 	RawQuery     string
 	tokens       []token
 	LogFormat    string
@@ -68,7 +77,7 @@ func NewQuery(queryStr string) (*Query, error) {
 
 // HasOutfile returns true if query result will be written to a CVS output file.
 func (q *Query) HasOutfile() bool {
-	return q.Outfile != ""
+	return q.Outfile != nil
 }
 
 // Has is a helper to determine whether a query contains a substring
@@ -193,10 +202,18 @@ func (q *Query) parseTokens(tokens []token) ([]token, error) {
 			q.Limit = i
 		case "outfile":
 			tokens, found = tokensConsume(tokens[1:])
-			if len(found) == 0 {
-				return tokens, errors.New(invalidQuery + unexpectedEnd)
+			switch len(found) {
+			case 1:
+				q.Outfile = &Outfile{FilePath: found[0].str, AppendMode: false}
+			case 2:
+				if found[0].str == "append" {
+					q.Outfile = &Outfile{FilePath: found[1].str, AppendMode: true}
+				} else {
+					return tokens, errors.New(invalidQuery + invalidQuery)
+				}
+			default:
+				return tokens, errors.New(invalidQuery + invalidQuery)
 			}
-			q.Outfile = found[0].str
 		case "logformat":
 			tokens, found = tokensConsume(tokens[1:])
 			if len(found) == 0 {
diff --git a/internal/mapr/query_test.go b/internal/mapr/query_test.go
index a0913fd..f03ccba 100644
--- a/internal/mapr/query_test.go
+++ b/internal/mapr/query_test.go
@@ -5,6 +5,48 @@ import (
 	"time"
 )
 
+func TestParseQueryOutfile(t *testing.T) {
+	queryStr := "select foo from bar outfile \"baz.csv\""
+
+	q, err := NewQuery(queryStr)
+	if err != nil {
+		t.Errorf("Query parse error: %s\n%v: %v", queryStr, q, err)
+	}
+
+	if q.Outfile == nil {
+		t.Errorf("Expected non-nil outfile: %s\n%v", queryStr, q)
+	}
+
+	if q.Outfile.FilePath != "baz.csv" {
+		t.Errorf("Expected \"baz.csv\" as outfile file path: %s\n%v", queryStr, q)
+	}
+
+	if q.Outfile.AppendMode {
+		t.Errorf("Expected append mode of outfile to be false: %s\n%v", queryStr, q)
+	}
+}
+
+func TestParseQueryOutfileAppend(t *testing.T) {
+	queryStr := "select foo from bar outfile append \"baz.csv\""
+
+	q, err := NewQuery(queryStr)
+	if err != nil {
+		t.Errorf("Query parse error: %s\n%v: %v", queryStr, q, err)
+	}
+
+	if q.Outfile == nil {
+		t.Errorf("Expected non-nil outfile: %s\n%v", queryStr, q)
+	}
+
+	if q.Outfile.FilePath != "baz.csv" {
+		t.Errorf("Expected \"baz.csv\" as outfile file path: %s\n%v", queryStr, q)
+	}
+
+	if !q.Outfile.AppendMode {
+		t.Errorf("Expected append mode of outfile to be true: %s\n%v", queryStr, q)
+	}
+}
+
 func TestParseQuerySimple(t *testing.T) {
 	errorQueries := []string{
 		"select",
@@ -30,7 +72,9 @@ func TestParseQuerySimple(t *testing.T) {
 		"select foo from bar where baz < 100 bay eq 12 group by foo, bar, baz " +
 			"order by foo limit 23 outfile \"result.csv\"",
 		"select foo from bar where baz < 100 bay eq 12 group by foo, bar, baz " +
-			"order by foo limit 23 outfile \"result.csv\" " +
+			"order by foo limit 23 outfile append \"result.csv\"",
+		"select foo from bar where baz < 100 bay eq 12 group by foo, bar, baz " +
+			"order by foo limit 23 outfile append \"result.csv\" " +
 			"set $foo = maskdigits(bar), $baz = 12, $bay = $foo;",
 	}