Release of DTail v1.0.0v1.0.0

3 files changed, 133 insertions, 0 deletions

diff --git a/mapr/logformat/default.go b/mapr/logformat/default.go
new file mode 100644
index 0000000..f0df5bc
--- /dev/null
+++ b/mapr/logformat/default.go
@@ -0,0 +1,23 @@
+package logformat
+
+import (
+	"errors"
+	"strings"
+)
+
+// MakeFieldsDEFAULT is the default log file mapreduce parser.
+func (p *Parser) MakeFieldsDEFAULT(maprLine string) (map[string]string, error) {
+	fields := make(map[string]string, 20)
+	splitted := strings.Split(maprLine, "|")
+
+	fields["$hostname"] = p.hostname
+
+	for _, kv := range splitted {
+		keyAndValue := strings.SplitN(kv, "=", 2)
+		if len(keyAndValue) != 2 {
+			return fields, errors.New("Error parsing mapr token: " + kv)
+		}
+		fields[strings.ToLower(keyAndValue[0])] = keyAndValue[1]
+	}
+	return fields, nil
+}
diff --git a/mapr/logformat/default_test.go b/mapr/logformat/default_test.go
new file mode 100644
index 0000000..a3c47fb
--- /dev/null
+++ b/mapr/logformat/default_test.go
@@ -0,0 +1,35 @@
+package logformat
+
+import (
+	"testing"
+)
+
+func TestDefaultLogFormat(t *testing.T) {
+	parser, err := NewParser("default")
+	if err != nil {
+		t.Errorf("Unable to create parser: %s", err.Error())
+	}
+
+	fields, err := parser.MakeFields("foo=bar|baz=bay")
+
+	if err != nil {
+		t.Errorf("Unable to parse: %s", err.Error())
+	}
+
+	if bar, ok := fields["foo"]; !ok {
+		t.Errorf("Expected field 'foo', but no such field there\n")
+	} else if bar != "bar" {
+		t.Errorf("Expected 'bar' stored in field 'foo', but got '%s'\n", bar)
+	}
+
+	if bay, ok := fields["baz"]; !ok {
+		t.Errorf("Expected field 'baz', but no such field there\n")
+	} else if bay != "bay" {
+		t.Errorf("Expected 'bay' stored in field 'baz', but got '%s'\n", bay)
+	}
+
+	fields, err = parser.MakeFields("foo=bar|bazbay")
+	if err == nil {
+		t.Errorf("Expected error but didn't: %s", err.Error())
+	}
+}
diff --git a/mapr/logformat/parser.go b/mapr/logformat/parser.go
new file mode 100644
index 0000000..b7c8c5c
--- /dev/null
+++ b/mapr/logformat/parser.go
@@ -0,0 +1,75 @@
+package logformat
+
+import (
+	"dtail/logger"
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+)
+
+// Parser is used to parse the mapreduce information from the server log files.
+type Parser struct {
+	hostname           string
+	logFormatName      string
+	makeFieldsFunc     reflect.Value
+	makeFieldsReceiver reflect.Value
+}
+
+// NewParser returns a new log parser.
+func NewParser(logFormatName string) (*Parser, error) {
+	hostname, err := os.Hostname()
+
+	if err != nil {
+		return nil, err
+	}
+
+	p := Parser{
+		hostname: hostname,
+	}
+
+	err = p.reflectLogFormat(logFormatName)
+	if err != nil {
+		return nil, err
+	}
+
+	return &p, nil
+}
+
+// The aim of this is that everyone can plug in their own mapr log format
+// parsing method to DTail. Just add a method MakeFieldsMODULENAME to type
+// Parser. Whereas MODULENAME must be a upeprcase string.
+func (p *Parser) reflectLogFormat(logFormatName string) error {
+	methodName := fmt.Sprintf("MakeFields%s", strings.ToUpper(logFormatName))
+
+	rt := reflect.TypeOf(p)
+	method, ok := rt.MethodByName(methodName)
+	if !ok {
+		return errors.New("No such mapr log format module: " + methodName)
+	}
+
+	p.makeFieldsFunc = method.Func
+	p.makeFieldsReceiver = reflect.ValueOf(p)
+
+	return nil
+}
+
+// MakeFields is for returning the fields from a given log line.
+func (p *Parser) MakeFields(maprLine string) (fields map[string]string, err error) {
+	inputValues := []reflect.Value{p.makeFieldsReceiver, reflect.ValueOf(maprLine)}
+	returnValues := p.makeFieldsFunc.Call(inputValues)
+
+	errInterface := returnValues[1].Interface()
+
+	if errInterface == nil {
+		fields, err = returnValues[0].Interface().(map[string]string), nil
+		logger.Trace("parser.MakeFields", fields, err)
+		return
+	}
+
+	fields, err = returnValues[0].Interface().(map[string]string), errInterface.(error)
+	logger.Trace("parser.MakeFields", fields, err)
+
+	return
+}