fix(titus): Lookup image form jenkins properties file (#3714)

restorting back some logic that was missed in refactor here (https://github.com/spinnaker/orca/pull/3688/files#diff-f4fd7e2fcf07f509c4f3be8808c5e76cL111-L113)

orca-clouddriver-provider-titus/src/main/groovy/com/netflix/spinnaker/orca/clouddriver/tasks/providers/aws/TitusAmazonServerGroupCreatorDecorator.java

@@ -23,6 +23,7 @@
 import com.netflix.spinnaker.orca.api.pipeline.models.StageExecution;
 import com.netflix.spinnaker.orca.api.pipeline.models.Trigger;
 import com.netflix.spinnaker.orca.pipeline.model.DockerTrigger;
+import com.netflix.spinnaker.orca.pipeline.model.JenkinsTrigger;
 import java.util.Map;
 import java.util.Optional;
 import org.springframework.stereotype.Component;
@@ -60,6 +61,10 @@ private Optional<String> getImageId(StageExecution stage) {
     if (trigger.getParameters().containsKey("imageName")) {
       imageId = (String) trigger.getParameters().get("imageName");
     }
+    if (Strings.isNullOrEmpty(imageId) && trigger instanceof JenkinsTrigger) {
+      JenkinsTrigger t = (JenkinsTrigger) trigger;
+      imageId = (String) t.getProperties().getOrDefault("imageName", null);
+    }
     if (Strings.isNullOrEmpty(imageId)) {
       imageId = (String) trigger.getOther().get("imageName");
     }

orca-clouddriver-provider-titus/src/test/groovy/com/netflix/spinnaker/orca/clouddriver/tasks/providers/aws/TitusAmazonServerGroupCreatorDecoratorSpec.groovy

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2020 Netflix, Inc.
+ *
+ * Licensed 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 com.netflix.spinnaker.orca.clouddriver.tasks.providers.aws
+
+import com.netflix.spinnaker.orca.pipeline.model.JenkinsTrigger
+import spock.lang.Specification
+import static com.netflix.spinnaker.orca.test.model.ExecutionBuilder.pipeline
+import static com.netflix.spinnaker.orca.test.model.ExecutionBuilder.stage
+
+class TitusAmazonServerGroupCreatorDecoratorSpec extends Specification {
+  def "should find image id from properties file"() {
+    given:
+    JenkinsTrigger jenkinsTrigger = new JenkinsTrigger("master", "job", 1, null)
+    jenkinsTrigger.properties.put("imageName", "imageFromProperties")
+
+    def pipeline = pipeline {
+      trigger = jenkinsTrigger
+      stage {
+        type = "deploy"
+      }
+    }
+
+    def stage = pipeline.stages[0]
+    TitusAmazonServerGroupCreatorDecorator decorator = new TitusAmazonServerGroupCreatorDecorator()
+
+    when:
+    decorator.modifyCreateServerGroupOperationContext(stage, stage.context)
+
+    then:
+    stage.context.imageId == jenkinsTrigger.properties.get("imageName")
+
+    when: 'trigger parameter specified'
+    stage.context.remove("imageId")
+    jenkinsTrigger.parameters.put("imageName", "imageFromParameters")
+    decorator.modifyCreateServerGroupOperationContext(stage, stage.context)
+
+    then: 'it takes precedence over props file'
+    stage.context.imageId == jenkinsTrigger.parameters.get("imageName")
+  }
+}