Add support to configure the number of browser processes per instance.

src/main/java/com/rmn/qa/aws/AwsVmManager.java

@@ -66,8 +66,13 @@ public class AwsVmManager implements VmManager {
     private AmazonEC2Client client;
     @VisibleForTesting AWSCredentials credentials;
     private Properties awsProperties;
-    public static final int CHROME_THREAD_COUNT = 5;
-    public static final int FIREFOX_IE_THREAD_COUNT = 1;
+
+    // How many chrome browser processes are allowed per EC2 instance.
+    public static int CHROME_THREAD_COUNT = 5;
+
+    // How many firefox browser processes are allowed per EC2 instance.
+    public static int FIREFOX_IE_THREAD_COUNT = 1;
+
     private String region;
 
 
@@ -95,6 +100,33 @@ public AwsVmManager() {
             client = new AmazonEC2Client();
         }
         AwsVmManager.setRegion(client, awsProperties, region);
+
+        // Allow the user to override the default settings for browser 
+        // processes per EC2 operating system instance.
+        String maxChromeThreads = awsProperties.getProperty("node_max_processes_chrome");
+        if ((null != maxChromeThreads) && (0 != maxChromeThreads.length())) {
+        	int newMaxChromeThreads = Integer.parseInt(maxChromeThreads);
+        	// Sanity check the maximum chrome instances setting.  Hard max of 128 sounds good.
+        	if ((newMaxChromeThreads >= 1) && (newMaxChromeThreads <= 128)) {
+        		log.info("Overriding factory default maximum chrome threads with: " + newMaxChromeThreads);
+        		CHROME_THREAD_COUNT = newMaxChromeThreads;
+        	} else {
+        		log.error("Invalid property setting for 'node_max_processes_chrome', ignoring '" + maxChromeThreads + "', using factory default of " + CHROME_THREAD_COUNT);
+        	}
+        }
+
+        String maxFirefoxThreads = awsProperties.getProperty("node_max_processes_firefox");
+        if ((null != maxFirefoxThreads) && (0 != maxFirefoxThreads.length())) {
+        	int newMaxFirefoxThreads = Integer.parseInt(maxFirefoxThreads);
+        	// Sanity check the maximum firefox instances setting.  Hard max of 128 sounds good.
+        	if ((newMaxFirefoxThreads >= 1) && (newMaxFirefoxThreads <= 128)) {
+        		log.info("Overriding factory default maximum chrome threads with: " + newMaxFirefoxThreads);
+        		FIREFOX_IE_THREAD_COUNT = newMaxFirefoxThreads;
+        	} else {
+        		log.error("Invalid property setting for 'node_max_processes_firefox', ignoring '" + maxFirefoxThreads + "', using factory default of " + FIREFOX_IE_THREAD_COUNT);
+        	}
+        }
+
     }
 
     public static void setRegion(AmazonEC2Client client, Properties awsProperties, String region) {

src/main/resources/grid_start_node.sh

@@ -0,0 +1,42 @@
+#!/bin/bash
+# ######################################################################################
+# Shell script to configure a Selenium Grid worker node and add it to the grid.
+# This is executed by this command in the crontab, as seen with "cronatab -l":
+#   @reboot /home/ubuntu/grid/grid_start_node.sh >> /home/ubuntu/grid/process.log 2>&1
+# 
+# ######################################################################################
+PATH=/sbin:/usr/sbin:/bin:/usr/bin
+cd /home/ubuntu/grid/
+
+# Call into AWS and figure out what our EC2 instance ID is.
+# Sometimes cron kicks off this script before the AWS/EC2 networking stack is awake.
+# We need to wait, polling for when the instance ID details beome available.
+echo "Grid Automation process started, looking up our EC2 Instance at `date`"
+export EC2_INSTANCE_ID=
+while [ -z "${EC2_INSTANCE_ID}" ] ; do
+   # Wait 1 seconds to let the network settle down on boot up and let AWS get all of
+   # the user-data zip file artifiacts in place.
+   sleep 1
+   export EC2_INSTANCE_ID="`wget -q -O - http://169.254.169.254/latest/meta-data/instance-id`"
+done
+
+echo "Retreived our EC2 Instance ID: $EC2_INSTANCE_ID at `date`"
+
+# Pull down the user data, which will be a zip file containing necessary information
+# This is placed in the user-data fild for the instance by the getUserData() and launchNodes() methods.
+export NODE_TEMPLATE="/home/ubuntu/grid/nodeConfigTemplate.json"
+curl http://169.254.169.254/latest/user-data -o /home/ubuntu/grid/data.zip
+
+# Now, unzip the data downloaded from the userdata
+unzip -o /home/ubuntu/grid/data.zip -d /home/ubuntu/grid/
+
+# Replace the instance ID in the node config file
+sed "s/<INSTANCE_ID>/$EC2_INSTANCE_ID/g" $NODE_TEMPLATE > /home/ubuntu/grid/nodeConfig.json
+
+# Finally, run the java process in a window so browsers can run
+xvfb-run --auto-servernum --server-args='-screen 0, 1600x1200x24' \
+   java -jar /home/ubuntu/grid/selenium-server-node.jar -role node \
+   -nodeConfig /home/ubuntu/grid/nodeConfig.json \
+   -Dwebdriver.chrome.driver="/home/ubuntu/grid/chromedriver" \
+   -log /home/ubuntu/grid/grid.log &
+

src/main/resources/patch_etc_hosts.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+# ###########################################################################
+# A shell script to patch the /etc/hosts file for new grid node hosts.
+# Stock hosts files on EC2 usually only contain the loopback addresses and
+# are missing the actual host name and the DHCP address binding.  This can
+# delay certain network operations.
+# This script patches the /etc/hosts file to contain the hostname on both the
+# loopback and DHCP based VPC IP address.
+# ###########################################################################
+PATH=/sbin:/usr/sbin:/bin:/usr/bin
+
+# Make certain we can find our host's EC2 instance ID.  This ensures that the
+# network stack is online and that it can get out to the rest of the netowrk.
+export EC2_INSTANCE_ID=
+while [ -z "${EC2_INSTANCE_ID}" ] ; do
+   # Wait 1 seconds to let the network settle down on boot up and let AWS get all of
+   # the user-data zip file artifiacts in place.
+   sleep 1
+   export EC2_INSTANCE_ID="`wget -q -O - http://169.254.169.254/latest/meta-data/instance-id`"
+done
+
+# Now we are certain the network stack is online, what is the host's IP?
+LOCALIP=`ifconfig | grep "inet addr" | grep -v "127.0.0" | cut -d':' -f2 | cut -d' ' -f1`
+HOSTNAME=`hostname`
+
+# Count the number of instacnces of the local ip in /etc/hosts. If this comes
+# back as zero then we know the local IP address needs to be added to the
+# /etc/hosts file.
+HASLOCALIP=`grep -c $LOCALIP /etc/hosts`
+
+# Count the number of instances of the host name in /etc/hosts.  If this comes
+# back as zero then we know the localhost line needs to be patched to include
+# the local host name. 
+HASHOSTNAME=`grep -c $HOSTNAME /etc/hosts`
+
+# Add the local hostname to /etc/hosts.
+if [ "0" -eq "$HASHOSTNAME" ] ; then
+   sudo sed -i -e "s/localhost/localhost $HOSTNAME/" /etc/hosts
+fi
+
+# Add the local IP to /etc/hosts.
+if [ "0" -eq "$HASLOCALIP" ] ; then
+   sudo bash -c "echo '# hostname added to support SeleniumGridScaler. ' >> /etc/hosts"
+   sudo bash -c "echo \"$LOCALIP $HOSTNAME\" >> /etc/hosts"
+fi
+
+# Add an /etc/hosts entry for the Hub IP address.
+HASHUBNODEADDR=`grep -c hubHost /home/ubuntu/grid/nodeConfig.json`
+while [ "0" -eq "$HASHUBNODEADDR" ] ; do
+   # Wait for the node setup script to pull down the hub's IP address.
+   sleep 1
+   export HASHUBNODEADDR=`grep -c hubHost /home/ubuntu/grid/nodeConfig.json`
+done
+
+# Lookup the IP address of the hubNode in the nodeConfig.json file.
+HUBNODEADDR=`grep hubHost /home/ubuntu/grid/nodeConfig.json | cut -d'"' -f4`
+
+# Only add the entry if it is actually necessary to do so.
+ETCHOSTSHUBCOUNT=`grep -c $HUBNODEADDR /etc/hosts`
+if [ "0" -eq "$ETCHOSTSHUBCOUNT" ] ; then
+   sudo bash -c "echo $HUBNODEADDR hubnode gridhead >> /etc/hosts"
+fi