Fix #3: Delay boostrap stage

Signed-off-by: jensenzhang <[email protected]>

pom.xml

@@ -79,6 +79,11 @@
   </dependencyManagement>
 
   <dependencies>
+    <dependency>
+      <groupId>javax.servlet</groupId>
+      <artifactId>servlet-api</artifactId>
+      <version>${servlet.version}</version>
+    </dependency>
     <dependency>
       <groupId>org.glassfish.jersey.containers</groupId>
       <artifactId>jersey-container-servlet</artifactId>
@@ -133,5 +138,6 @@
     <httpcomponents.version>4.5.3</httpcomponents.version>
     <slf4j.version>1.7.21</slf4j.version>
     <jackson.version>2.8.9</jackson.version>
+    <servlet.version>2.5</servlet.version>
   </properties>
 </project>

src/main/java/org/snlab/unicorn/Bootstrap.java

@@ -0,0 +1,27 @@
+package org.snlab.unicorn;
+
+import java.util.Collection;
+
+import javax.servlet.ServletConfig;
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.snlab.unicorn.orchestrator.OrchestratorInfo;
+import org.snlab.unicorn.orchestrator.OrchestratorInfoReader;
+import org.snlab.unicorn.register.UnicornRegister;
+import org.snlab.unicorn.register.UnicornRegisterBuilder;
+
+public class Bootstrap extends HttpServlet {
+    private final static Logger LOG = LoggerFactory.getLogger(Bootstrap.class);
+
+    @Override
+    public void init(ServletConfig config) throws ServletException {
+        LOG.info("Starting bootstrap stage...");
+        // Register to orchestrator
+        Collection<OrchestratorInfo> infos = OrchestratorInfoReader.read(UnicornDefinitions.OrchestratorConfig.CONFIG_PATH);
+        UnicornRegister register = new UnicornRegisterBuilder().addOrchestrators(infos).build();
+        register.register();
+    }
+}

src/main/java/org/snlab/unicorn/UnicornApplication.java

@@ -2,20 +2,14 @@
 
 import org.glassfish.jersey.media.sse.SseFeature;
 import org.glassfish.jersey.server.ResourceConfig;
-import org.snlab.unicorn.orchestrator.OrchestratorInfo;
-import org.snlab.unicorn.orchestrator.OrchestratorInfoReader;
-import org.snlab.unicorn.register.UnicornRegister;
-import org.snlab.unicorn.register.UnicornRegisterBuilder;
-
-import java.util.Collection;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class UnicornApplication extends ResourceConfig {
+    private final static Logger LOG = LoggerFactory.getLogger(UnicornApplication.class);
+
     public UnicornApplication() {
         super(UnicornService.class, SseFeature.class);
-
-        // Register to orchestrator
-        Collection<OrchestratorInfo> infos = OrchestratorInfoReader.read(UnicornDefinitions.OrchestratorConfig.CONFIG_PATH);
-        UnicornRegister register = new UnicornRegisterBuilder().addOrchestrators(infos).build();
-        register.register();
+        LOG.info("Starting unicorn application...");
     }
 }

src/main/webapp/WEB-INF/web.xml

@@ -13,6 +13,11 @@
         <load-on-startup>1</load-on-startup>
         <async-supported>true</async-supported>
     </servlet>
+    <servlet>
+        <servlet-name>Bootstrap</servlet-name>
+        <servlet-class>org.snlab.unicorn.Bootstrap</servlet-class>
+        <load-on-startup>2</load-on-startup>
+    </servlet>
     <servlet-mapping>
         <servlet-name>Jersey Web Application</servlet-name>
         <url-pattern>/experimental/v1/*</url-pattern>