move stream to rabit part, support rabit on yarn

subtree/rabit/tracker/rabit_yarn.py

@@ -14,7 +14,13 @@ import rabit_tracker as tracker
 WRAPPER_PATH = os.path.dirname(__file__) + '/../wrapper'
 YARN_JAR_PATH = os.path.dirname(__file__) + '/../yarn/rabit-yarn.jar'
 
-assert os.path.exists(YARN_JAR_PATH), ("cannot find \"%s\", please run build.sh on the yarn folder" % YARN_JAR_PATH)
+if not os.path.exists(YARN_JAR_PATH):
+    warnings.warn("cannot find \"%s\", I will try to run build" % YARN_JAR_PATH)
+    cmd = 'cd %;./build.sh' % os.path.dirname(__file__) + '/../yarn/'
+    print cmd
+    subprocess.check_call(cmd, shell = True, env = os.environ) 
+    assert os.path.exists(YARN_JAR_PATH), "failed to build rabit-yarn.jar, try it manually"
+
 hadoop_binary  = 'hadoop'
 # code 
 hadoop_home = os.getenv('HADOOP_HOME')

subtree/rabit/yarn/build.sh

@@ -1,4 +1,8 @@
 #!/bin/bash
+if [ -z "$HADOOP_PREFIX" ]; then
+    echo "cannot found $HADOOP_PREFIX in the environment variable, please set it properly"
+    exit 1
+fi
 CPATH=`${HADOOP_PREFIX}/bin/hadoop classpath`
 javac -cp $CPATH -d bin src/org/apache/hadoop/yarn/rabit/*
 jar cf rabit-yarn.jar -C bin .