In that post it was developed a simple Rest example. For testing the application, file was copied into a web server (Tomcat for example), and then accessing to http://localhost:8080/RestServer/characters/1 information of character 1 was returned.
In current post I am going to explain how to transform that application to a Google App Engine and be deployed into Google’s infrastructure using Maven. Of course in this case we are going to deploy a Rest Spring MVC application, but same approach can be used for migrating a Spring MVC web application (or any other application developed with other web framework) to GAE.
First of all, obviously you should create a Google Account and register a new application (remember the name because will be used in next step). After that you can start the migration.
Three changes are required, create appengine-web.xml defining application name; add server tag to settings.xml with Google account information, and modify pom.xml for adding GAE plugin and its dependencies.
Let’s start with appengine-web.xml. This file is used by GAE to configure application and is created into WEB-INF directory (at same level of web.xml).
01 02 03 04 05 06 07 08 09 10 11 12 | <?xml version="1.0" encoding="utf-8"?><appengine-web-app xmlns="http://appengine.google.com/ns/1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://appengine.google.com/ns/1.0 http://googleappengine.googlecode.com/svn/branches/1.2.1/java/docs/appengine-web.xsd"> <application>alexsotoblog</application> <version>1</version> <system-properties> <property name="java.util.logging.config.file" value="WEB-INF/classes/logging.properties"/> </system-properties> <precompilation-enabled>false</precompilation-enabled> <sessions-enabled>true</sessions-enabled></appengine-web-app> |
The most important field is application tag. This tag contains the name of our application (defined when you register a new Google Application).
Other tags are version, system properties and environment variables, and misc configuration like if you want a precompilation to enhance performance or if your application requires sessions.
And your project should not be modified anymore, now only Maven files will be touched.
In settings.xml, account information should be added:
01 02 03 04 05 06 07 08 09 10 11 12 13 | <settings xmlns="http://maven.apache.org/SETTINGS/1.1.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.1.0 http://maven.apache.org/xsd/settings-1.1.0.xsd"> <localRepository>/media/share/maven_repo</localRepository> <servers> <server> <id>appengine.google.com</id> <username>my_account@gmail.com</username> <password>my_password</password> </server> </servers> </settings> |
See that it is as easy as registering any other server in Maven.
And finally the most tedious part, modifying pom.xml.
First thing is adding new properties:
1 2 3 4 5 6 7 | <gae.home>/media/share/maven_repo/com/google/appengine/appengine-java-sdk/1.5.5/appengine-java-sdk-1.5.5</gae.home><gaeApplicationName>alexsotoblog</gaeApplicationName><gaePluginVersion>0.9.0</gaePluginVersion><gae.version>1.5.5</gae.version><!-- Upload to http://test.latest.<applicationName>.appspot.com by default --><gae.application.version>test</gae.application.version> |
At first line we are defining Appengine Java SDK location. If you have already installed then insert location in this tag, if not, copy same location of this pom and simply change maven repository directory, in my case /media/share/maven_repo, to yours. Typically your Maven repository location will be /home/user/.m2/repositories. Maven will download SDK for you at deploy time.
Next step is adding Maven GAE repository.
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 | <repositories> <repository> <id>maven-gae-plugin-repo</id> <name>maven-gae-plugin repository</name> </repository></repositories><pluginRepositories> <pluginRepository> <id>maven-gae-plugin-repo</id> <name>Maven Google App Engine Repository</name> </pluginRepository></pluginRepositories> |
Because our project is dummy project, Datanucleus are not used. In case of more complex projects, that database access is required using, for example JDO, next dependencies should be added:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | <dependency> <groupId>javax.jdo</groupId> <artifactId>jdo2-api</artifactId> <version>2.3-eb</version> <exclusions> <exclusion> <groupId>javax.transaction</groupId> <artifactId>transaction-api</artifactId> </exclusion> </exclusions></dependency><dependency> <groupId>com.google.appengine.orm</groupId> <artifactId>datanucleus-appengine</artifactId> <version>1.0.6.final</version></dependency><dependency> <groupId>org.datanucleus</groupId> <artifactId>datanucleus-core</artifactId> <version>1.1.5</version> <scope>runtime</scope> <exclusions> <exclusion> <groupId>javax.transaction</groupId> <artifactId>transaction-api</artifactId> </exclusion> </exclusions></dependency><dependency> <groupId>com.google.appengine</groupId> <artifactId>geronimo-jta_1.1_spec</artifactId> <version>1.1.1</version> <scope>runtime</scope></dependency><dependency> <groupId>com.google.appengine</groupId> <artifactId>geronimo-jpa_3.0_spec</artifactId> <version>1.1.1</version> <scope>runtime</scope></dependency> |
And in case you are using Datanucleus, maven-datanucleus-plugin should be registered. Take care to configure it properly depending on your project.
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | <plugin> <groupId>org.datanucleus</groupId> <artifactId>maven-datanucleus-plugin</artifactId> <version>1.1.4</version> <configuration> <!-- Make sure this path contains your persistent classes! --> <mappingIncludes>**/model/*.class</mappingIncludes> <verbose>true</verbose> <enhancerName>ASM</enhancerName> <api>JDO</api> </configuration> <executions> <execution> <phase>compile</phase> <goals> <goal>enhance</goal> </goals> </execution> </executions> <dependencies> <dependency> <groupId>org.datanucleus</groupId> <artifactId>datanucleus-core</artifactId> <version>1.1.5</version> <exclusions> <exclusion> <groupId>javax.transaction</groupId> <artifactId>transaction-api</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.datanucleus</groupId> <artifactId>datanucleus-rdbms</artifactId> <version>1.1.5</version> </dependency> <dependency> <groupId>org.datanucleus</groupId> <artifactId>datanucleus-enhancer</artifactId> <version>1.1.5</version> </dependency> </dependencies></plugin> |
Now Google App Engine dependencies are added.
01 02 03 04 05 06 07 08 09 10 11 | <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-api-1.0-sdk</artifactId> <version>${gae.version}</version></dependency><dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-tools-api</artifactId> <version>1.3.7</version></dependency> |
Then if you want to test GAE functionalities (not used in our dummy project), next GAE libraries are added:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 | <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-api-labs</artifactId> <version>${gae.version}</version> <scope>test</scope></dependency><dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-api-stubs</artifactId> <version>${gae.version}</version> <scope>test</scope></dependency><dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-testing</artifactId> <version>${gae.version}</version> <scope>test</scope></dependency> |
Next change is a modification on maven-war-plugin including appengine-web.xml into generated package:
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 | <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <configuration> <webResources> <resource> <directory>src/main/webapp</directory> <filtering>true</filtering> <includes> <include>**/appengine-web.xml</include> </includes> </resource> </webResources> </configuration></plugin> |
And finally adding maven-gae-plugin and configuring it to upload application to appspot.
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 | <plugin> <groupId>net.kindleit</groupId> <artifactId>maven-gae-plugin</artifactId> <version>${gaePluginVersion}</version> <configuration> <serverId>appengine.google.com</serverId> </configuration> <dependencies> <dependency> <groupId>net.kindleit</groupId> <artifactId>gae-runtime</artifactId> <version>${gae.version}</version> <type>pom</type> </dependency> </dependencies></plugin> |
See that <serviceId> tag contains the server name defined previously in settings.xml file.
Also if you are using maven-release-plugin you can upload application to the appspot automatically, during release:perform goal:
1 2 3 4 5 6 7 8 | <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-release-plugin</artifactId> <version>2.2.1</version> <configuration> <goals>gae:deploy</goals> </configuration></plugin> |
Now run gae:deploy goal. If you have already installed Appengine Java SDK, then your application will be uploaded to your GAE site. But if it is the first time you run the plugin, you will receive an error. Do not panic, this error occurs because Maven plugin does not find Appengine SDK into directory you specified in <gae.home> tag. But if you have configured gae.home location into your local Maven repository, simply run gae:unpack goal, and SDK will be installed correctly so when you rerun gae:deploy your application will be uploaded into Google infrastructure.
In post example you can go to http://alexsotoblog.appspot.com/characters/1http://alexsotoblog.appspot.com/characters/1 and character information in JSON format is displayed into your browser.
As I have noted at the beginning of the post, the same process can be used for any web application, not only for Spring Rest MVC.
Because of teaching purpose all modifications have been made into application pom. My advice is that you create a parent pom with GAE related tags, so each project that must be uploaded into Google App Engine extends from same pom file.
I wish you have found this post useful.
This week I am at devoxx, meet me there ;) I will be speaking on Thursday 17 at 13:00 about Speeding Up Javascript & CSS Download Times With Aggregation and Minification.
Full pom file:
001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 | <?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" <modelVersion>4.0.0</modelVersion> <groupId>org.springframework</groupId> <artifactId>rest</artifactId> <name>Rest</name> <packaging>war</packaging> <version>1.0.0-BUILD-SNAPSHOT</version> <properties> <java-version>1.6</java-version> <org.springframework-version>3.0.4.RELEASE</org.springframework-version> <org.aspectj-version>1.6.9</org.aspectj-version> <org.slf4j-version>1.5.10</org.slf4j-version> <!-- Specify AppEngine version for your project. It should match SDK version pointed to by ${gae.home} property (Typically, one used by your Eclipse plug-in) --> <gae.home>/home/alex/.m2/repository/com/google/appengine/appengine-java-sdk/1.5.5/appengine-java-sdk-1.5.5</gae.home> <gaeApplicationName>alexsotoblog</gaeApplicationName> <gaePluginVersion>0.9.0</gaePluginVersion> <gae.version>1.5.5</gae.version> <!-- Upload to http://test.latest.<applicationName>.appspot.com by default --> <gae.application.version>test</gae.application.version> </properties> <dependencies> <!-- Rest --> <dependency> <groupId>com.sun.xml.bind</groupId> <artifactId>jaxb-impl</artifactId> <version>2.2.4-1</version> </dependency> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-core-lgpl</artifactId> <version>1.8.5</version> </dependency> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-mapper-lgpl</artifactId> <version>1.8.5</version> </dependency> <!-- GAE libraries for local testing as described here: http://code.google.com/appengine/docs/java/howto/unittesting.html --> <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-api-labs</artifactId> <version>${gae.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-api-stubs</artifactId> <version>${gae.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-testing</artifactId> <version>${gae.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-api-1.0-sdk</artifactId> <version>${gae.version}</version> </dependency> <dependency> <groupId>com.google.appengine</groupId> <artifactId>appengine-tools-api</artifactId> <version>1.3.7</version> </dependency> <!-- Spring --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>${org.springframework-version}</version> <exclusions> <!-- Exclude Commons Logging in favor of SLF4j --> <exclusion> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${org.springframework-version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-oxm</artifactId> <version>${org.springframework-version}</version> </dependency> <!-- AspectJ --> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>${org.aspectj-version}</version> </dependency> <!-- Logging --> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-api</artifactId> <version>${org.slf4j-version}</version> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>jcl-over-slf4j</artifactId> <version>${org.slf4j-version}</version> <scope>runtime</scope> </dependency> <dependency> <groupId>org.slf4j</groupId> <artifactId>slf4j-log4j12</artifactId> <version>${org.slf4j-version}</version> <scope>runtime</scope> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>1.2.15</version> <exclusions> <exclusion> <groupId>javax.mail</groupId> <artifactId>mail</artifactId> </exclusion> <exclusion> <groupId>javax.jms</groupId> <artifactId>jms</artifactId> </exclusion> <exclusion> <groupId>com.sun.jdmk</groupId> <artifactId>jmxtools</artifactId> </exclusion> <exclusion> <groupId>com.sun.jmx</groupId> <artifactId>jmxri</artifactId> </exclusion> </exclusions> <scope>runtime</scope> </dependency> <!-- @Inject --> <dependency> <groupId>javax.inject</groupId> <artifactId>javax.inject</artifactId> <version>1</version> </dependency> <!-- Servlet --> <dependency> <groupId>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>javax.servlet</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <!-- Test --> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.7</version> <scope>test</scope> </dependency> </dependencies> <repositories> <!-- For testing against latest Spring snapshots --> <repository> <id>org.springframework.maven.snapshot</id> <name>Spring Maven Snapshot Repository</name> <releases> <enabled>false</enabled> </releases> <snapshots> <enabled>true</enabled> </snapshots> </repository> <!-- For developing against latest Spring milestones --> <repository> <id>org.springframework.maven.milestone</id> <name>Spring Maven Milestone Repository</name> <snapshots> <enabled>false</enabled> </snapshots> </repository> <!-- GAE repositories --> <repository> <id>maven-gae-plugin-repo</id> <name>maven-gae-plugin repository</name> </repository> </repositories> <pluginRepositories> <pluginRepository> <id>maven-gae-plugin-repo</id> <name>Maven Google App Engine Repository</name> </pluginRepository> </pluginRepositories> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>${java-version}</source> <target>${java-version}</target> </configuration> </plugin> <!-- Adding appengine-web into war --> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <configuration> <webResources> <resource> <directory>src/main/webapp</directory> <filtering>true</filtering> <includes> <include>**/appengine-web.xml</include> </includes> </resource> </webResources> <warName>abc</warName> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <executions> <execution> <id>install</id> <phase>install</phase> <goals> <goal>sources</goal> </goals> </execution> </executions> </plugin> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>aspectj-maven-plugin</artifactId> <!-- Have to use version 1.2 since version 1.3 does not appear to work with ITDs --> <version>1.2</version> <dependencies> <!-- You must use Maven 2.0.9 or above or these are ignored (see MNG-2972) --> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>${org.aspectj-version}</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjtools</artifactId> <version>${org.aspectj-version}</version> </dependency> </dependencies> <executions> <execution> <goals> <goal>compile</goal> <goal>test-compile</goal> </goals> </execution> </executions> <configuration> <outxml>true</outxml> <source>${java-version}</source> <target>${java-version}</target> </configuration> </plugin> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-surefire-plugin</artifactId> <configuration> <junitArtifactName>junit:junit</junitArtifactName> </configuration> </plugin> <plugin> <groupId>org.codehaus.mojo</groupId> <artifactId>tomcat-maven-plugin</artifactId> <version>1.0-beta-1</version> </plugin> <!-- The actual maven-gae-plugin. Type "mvn gae:run" to run project, "mvn gae:deploy" to upload to GAE. --> <plugin> <groupId>net.kindleit</groupId> <artifactId>maven-gae-plugin</artifactId> <version>${gaePluginVersion}</version> <configuration> <serverId>appengine.google.com</serverId> </configuration> <dependencies> <dependency> <groupId>net.kindleit</groupId> <artifactId>gae-runtime</artifactId> <version>${gae.version}</version> <type>pom</type> </dependency> </dependencies> </plugin> </plugins> </build></project> |
Download Code.
Music: http://www.youtube.com/watch?v=Nba3Tr_GLZU
Reference: Spring MVC and REST at Google App Engine from our JCG partner Alex Soto at the One Jar To Rule Them All blog.
Related Articles :
Excellent article. Can you add how to test the GAE app in dev mode without uploading it to the server as well.
run maven goal:
mvn jetty:run (it will run this application on jetty server on your localhost)
Once, server starts: go to browser > http://localhost:8080/characters/1
Thanks,
Rajan
Very useful, thank you :)))
Very usefull!!
I put true into my appengine-web.xml
Hi,
I am facing following issue can any one guide me what am I doing wrong. Struggling for almost a week. I have downloaded this example and trying to run but its not working. [ERROR] Unable to execute AppCfg
java.lang.ExceptionInInitializerError
at com.google.appengine.tools.util.Logging.initializeLogging(Logging.java:35)
at com.google.appengine.tools.admin.AppCfg.main(AppCfg.java:94)
at net.kindleit.gae.EngineGoalBase$1.run(EngineGoalBase.java:318)
Caused by: java.lang.IllegalArgumentException: Unable to find C:Erndinstallslibshared
at com.google.appengine.tools.info.SdkInfo._getLibs(SdkInfo.java:76)
at com.google.appengine.tools.info.SdkInfo.getLibsRecursive(SdkInfo.java:69)
at com.google.appengine.tools.info.SdkInfo.determineSharedLibFiles(SdkInfo.java:302)
at com.google.appengine.tools.info.SdkInfo.init(SdkInfo.java:237)
at com.google.appengine.tools.info.SdkInfo.getSdkRoot(SdkInfo.java:190)
at com.google.appengine.tools.info.SdkImplInfo.(SdkImplInfo.java:19)
… 3 more