Normalizes Maven build logs

Normalizes the Maven build log format so that the build messages go
through the operator log. This makes the logs more easily parseable
by log collection tools due to the format of the previous Maven build
log being different.

This solves GH issue #2268
diff --git a/pkg/util/maven/maven.go b/pkg/util/maven/maven.go
index 081e35e..3979799 100644
--- a/pkg/util/maven/maven.go
+++ b/pkg/util/maven/maven.go
@@ -18,6 +18,7 @@
 package maven
 
 import (
+	"bufio"
 	"context"
 	"fmt"
 	"io"
@@ -117,12 +118,6 @@
 
 	cmd := exec.CommandContext(c, mvnCmd, args...)
 	cmd.Dir = ctx.Path
-	cmd.Stderr = os.Stderr
-	if ctx.Stdout != nil {
-		cmd.Stdout = ctx.Stdout
-	} else {
-		cmd.Stdout = os.Stdout
-	}
 
 	var mavenOptions string
 	if len(ctx.ExtraMavenOpts) > 0 {
@@ -168,7 +163,36 @@
 	Log.WithValues("timeout", timeout.String(), "MAVEN_OPTS", mavenOptions).
 		Infof("executing: %s", strings.Join(cmd.Args, " "))
 
-	return cmd.Run()
+	stdOut, error := cmd.StdoutPipe()
+	if error != nil {
+		return nil
+	}
+
+	error = cmd.Start()
+
+	if error != nil {
+		return error
+	}
+
+	scanner := bufio.NewScanner(stdOut)
+
+	Log.Debug("About to start parsing the Maven output")
+
+	for scanner.Scan() {
+		line := scanner.Text()
+
+		mavenLog, parseError := ParseLog(line)
+
+		if parseError != nil {
+			// Do not abort the build because parsing failed ... the build may have succeeded
+			Log.Error(parseError, "Unable to parse maven log")
+		} else {
+			NormalizeLog(mavenLog)
+		}
+	}
+	Log.Debug("Finished parsing Maven output")
+
+	return cmd.Wait()
 }
 
 // ParseGAV decode a maven artifact id to a dependency definition.
diff --git a/pkg/util/maven/maven_log.go b/pkg/util/maven/maven_log.go
new file mode 100644
index 0000000..57647e4
--- /dev/null
+++ b/pkg/util/maven/maven_log.go
@@ -0,0 +1,63 @@
+/*
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements.  See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You under the Apache License, Version 2.0
+(the "License"); you may not use this file except in compliance with
+the License.  You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package maven
+
+import (
+	"encoding/json"
+	"github.com/apache/camel-k/pkg/util/log"
+)
+
+type MavenLog struct {
+	Level            string `json:"level"`
+	Ts               string `json:"ts"`
+	Logger           string `json:"logger"`
+	Msg              string `json:"msg"`
+	Class            string `json:"class"`
+	CallerMethodName string `json:"caller_method_name"`
+	CallerFileName   string `json:"caller_file_name"`
+	CallerLineNumber int    `json:"caller_line_number"`
+	Thread           string `json:"thread"`
+}
+
+const (
+	TRACE = "TRACE"
+	DEBUG = "DEBUG"
+	INFO  = "INFO"
+	WARN  = "WARN"
+	ERROR = "ERROR"
+	FATAL = "FATAL"
+)
+
+func ParseLog(line string) (mavenLog MavenLog, error error) {
+	error = json.Unmarshal([]byte(line), &mavenLog)
+
+	return mavenLog, error
+}
+
+func NormalizeLog(mavenLog MavenLog) {
+	logger := log.WithName("maven.build")
+
+	switch mavenLog.Level {
+	case DEBUG, TRACE:
+		logger.Debug(mavenLog.Msg)
+	case INFO, WARN:
+		logger.Info(mavenLog.Msg)
+	case ERROR, FATAL:
+		logger.Errorf(nil, mavenLog.Msg)
+	}
+}