Polishing.

Extract docker credentials into properties file.

See #2541

Author: mp911de

Jenkinsfile

@@ -35,7 +35,7 @@ pipeline {
 			}
 			steps {
 				script {
-					docker.withRegistry('', 'hub.docker.com-springbuildmaster') {
+					docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
 						docker.image(p['docker.java.main.image']).inside(p['docker.java.inside.basic']) {
 							sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml clean dependency:list verify -Dsort -U -B'
 						}
@@ -63,7 +63,7 @@ pipeline {
 
 			steps {
 				script {
-					docker.withRegistry('', 'hub.docker.com-springbuildmaster') {
+					docker.withRegistry(p['docker.registry'], p['docker.credentials']) {
 						docker.image(p['docker.java.main.image']).inside(p['docker.java.inside.basic']) {
 							sh 'MAVEN_OPTS="-Duser.name=jenkins -Duser.home=/tmp/jenkins-home" ./mvnw -s settings.xml -Pci,artifactory ' +
 									'-Dartifactory.server=https://repo.spring.io ' +

ci/pipeline.properties

@@ -17,3 +17,7 @@ docker.cassandra.3.version=3.11.11
 # Docker environment settings
 docker.java.inside.basic=-v $HOME:/tmp/jenkins-home
 docker.java.inside.docker=-u root -v /var/run/docker.sock:/var/run/docker.sock -v /usr/bin/docker:/usr/bin/docker -v $HOME:/tmp/jenkins-home
+
+# Credentials
+docker.registry=
+docker.credentials=hub.docker.com-springbuildmaster