boost ptree

This is an awesome post on how to use ptree for json processing. http://zenol.fr/blog/boost-property-tree/en.html

JSON in Java

Add to your Maven dependency

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<dependency> <groupId>org.glassfish</groupId> <artifactId>javax.json</artifactId> <version>1.0.4</version> </dependency>

Demo:

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String json = "{\"id\":3}"; JsonReader reader = Json.createReader(new StringReader(json)); JsonObject rootObject = reader.readObject(); reader.close(); int devID = rootObject.getInt("id"); String sDevID = Integer.toString(devID);

Add a new Ambari Service

1. get java home
    from resource_management import Script
   
    config = Script.get_config()
    java_home = config['hostLevelParams']['java_home']

    # /usr/lib/jvm/java

2. default log directory
/var/lib/ambari-agent/data

Add ports mapping to the HDP 2.5 VMware Sandbox

HDP 2.5 Sandbox VM:
    ssh root@IP -p 22

HDP 2.5 Sandbox Container
    ssh root@IP -p 2222

Note: here the IP is the public IP address for VM. It's NOT the IP for Container.

1) login to the Sandbox VM

$ ssh root@IP -p 22

2) Disable sandbox.service

$ systemctl disable sandbox.service

3) Reboot the VM

$ init 6

4) Modify sandbox start script

$ vi /root/start_scripts/start_sandbox.sh

Go search "-p 2222:22 \"

Add a new line after that, like:

    -p 1234:1234 \

save and exit.

5) Delete existing sandbox container

$ docker rm sandbox

6) Enable sandbox.service

systemctl enable sandbox.service

7) Reboot the VM

$ init 6

8) Verify new ports

$ docker ps |grep 1234

You should see that 1234 is now in the list.

9) Bring up webapp listening at port 1234

10) Verify that you can access IP:1234 via browser from a 3rd machine.

Reference: How to add ports to the HDP 2.5 VirtualBox Sandbox

Paths in a JAR file

Suppose a JAR file has the following contents:
$ jar -jar simple-service-1.0-SNAPSHOT.jar

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159 Mon Nov 28 09:22:20 EST 2016 META-INF/MANIFEST.MF 0 Mon Nov 28 09:22:20 EST 2016 META-INF/ 0 Mon Nov 28 09:22:20 EST 2016 backup/ 2333 Mon Nov 28 09:22:20 EST 2016 backup/backupController.js 231 Mon Nov 28 09:22:20 EST 2016 backup/backup.html 0 Mon Nov 28 09:22:20 EST 2016 WEB-INF/ 1081 Mon Nov 28 09:22:20 EST 2016 WEB-INF/web.xml 0 Mon Nov 28 09:22:20 EST 2016 com/ 0 Mon Nov 28 09:22:20 EST 2016 com/example/ 1727 Mon Nov 28 09:22:20 EST 2016 com/example/Main.class 579 Mon Nov 28 09:22:20 EST 2016 com/example/MyResource.class 556 Mon Nov 28 09:22:20 EST 2016 com/example/MyResource2.class 0 Mon Nov 28 09:22:20 EST 2016 config/ 2117 Mon Nov 28 09:22:20 EST 2016 config/configController.js 230 Mon Nov 28 09:22:20 EST 2016 config/config.html 0 Mon Nov 28 09:22:20 EST 2016 restore/ 2137 Mon Nov 28 09:22:20 EST 2016 restore/restoreController.js 232 Mon Nov 28 09:22:20 EST 2016 restore/restore.html 2818 Mon Nov 28 09:22:20 EST 2016 index.html 2821 Mon Nov 28 09:22:20 EST 2016 hdboost.js

1. Root of a JAR file:

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// file:/home/fos/simple-service-1.0-SNAPSHOT.jar String webdir = Main.class.getProtectionDomain().getCodeSource().getLocation().toExternalForm(); // jar:file:/home/fos/simple-service-1.0-SNAPSHOT.jar!/ webdir = "jar:" + webdir + "!/"; webapp.setResourceBase(webdir);

2. Path of a resource in a JAR file:
take "index.html" for example:

1 2	// jar:file:/home/fos/simple-service-1.0-SNAPSHOT.jar!/index.html String webdir = Main.class.getClassLoader().getResource("index.html").toExternalForm();

Another example with "WEB-INF"

1 2	// WEB-INF: jar:file:/home/fos/simple-service-1.0-SNAPSHOT.jar!/WEB-INF/ String webdir = Main.class.getClassLoader().getResource("WEB-INF").toExternalForm();

combine two jar files

There are two jar files in current directory:

• jetty-all-uber.jar
• hello-world-0.1-SNAPSHOT.jar

1. make a temp directory
mkdir tmp
2. cd tmp
    jar -xf ../hello-world-0.1-SNAPSHOT.jar
    jar -xf ../jetty-all-uber.jar
3. cd ..
    jar -cvf my.jar -C tmp .

The above commands create a combined jar file my.jar in current directory.


Test HelloWorld with:
fos@ubuntu:~/dev/jetty-demo$ java -cp my.jar org.example.HelloWorld

If you want to make your jar file as an application, please refer to:
Running JAR-Packaged Software

with which you can run the HelloWorld with:
fos@ubuntu:~/dev/jetty-demo$ java -jar my.jar

How to start http server with Python

Change to the directory where you want to start your http server:
Python2:
    python -m SimpleHTTPServer
Python3:
    python3 -m http.server