Release of DTail v1.0.0v1.0.0

1 files changed, 75 insertions, 0 deletions

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
+}