Audi helps you time the lights!

The latest technology to come out of Audi shows the driver the perfect speed to drive in order to avoid red lights at upcoming traffic lights! Admittedly, the traffic lights in a German town were modified for the technology to work, but it's still an awesome idea! Source: http://blogs.cars.com/kickingtires/2008/07/audi-takes-on-s.html

Full dyno day results

Full results from the dyno day are now online: http://www.petrolmonkey.com/dyno-results.html

Dyno Day Result

I organised a second OZVR4 dyno day for today and it went very well. 19 Cars were there (17 8th gen and 2 6th gen). Shots from the day will hopefully end up in High Performance Imports (hpi.com.au). Here's my graph, I was 4th for day, which is pretty respectable seeing as I have no aftermarket fuel control like 1st, 2nd and 3rd do :)

Switchable Grails DataSource

As part of my day job I needed to write an administration app that could be easily pointed at multiple environments. To achieve this I used a technique I found a while ago based on Spring's AbstractRoutingDataSource. It basically works by using a facade to switch the connection between one to many child data sources. First off SwitchableDataSource.groovy

package com.leebutts 
import org.springframework.jdbc.datasource
                 .lookup.AbstractRoutingDataSource 
import com.leebutts.Environment 
import org.springframework.context.ApplicationContextAware 
import org.springframework.context.ApplicationContext 
import javax.sql.DataSource 
import org.springframework.jdbc.datasource.DriverManagerDataSource 

class SwitchableDataSource extends AbstractRoutingDataSource 
    implements ApplicationContextAware { 
    def applicationContext 
    
    public void setApplicationContext(ApplicationContext 
                                           applicationContext) { 
        this.applicationContext = applicationContext 
    } 

    protected DataSource determineTargetDataSource() { 
        DriverManagerDataSource ds = 
                        super.determineTargetDataSource(); 
        def env = EnvironmentHolder.getEnvironment() 
        if (env && env.passwordRequired && ds) { 
            ds.setPassword(env.password) 
        } 
        return ds 
    } 

    protected Object determineCurrentLookupKey() { 
        def env = EnvironmentHolder.getEnvironment() 
        return env?.id ?: Environment.list()[0]?.id 
    } 
}

SwitchableDataSource is the facade that delegates to the list of standard DriverManager data sources. They are defined in grails-app/conf/spring/resources.groovy using the environment settings from the Environment class. Here's my spring config in resources.groovy:

import com.leebutts.SwitchableDataSource 
import com.leebutts.Environment 
import org.springframework.jdbc.datasource.DriverManagerDataSource 

beans = { 
    parentDataSource(DriverManagerDataSource) {
        bean -> bean.'abstract' = true; 
        driverClassName = 'com.mysql.jdbc.Driver' 
        username = "root" 
    } 
    
    Environment.list().each {env -> 
        "${env.prefix}DataSource"(DriverManagerDataSource) {bean -> 
            bean.parent = parentDataSource 
            bean.scope = 'prototype' 
            def port = env.port ?: 3306 
            url = "jdbc:mysql://${env.host}:${port}/switchingDemo" 
            if (env.user) { 
                username = env.user 
            } 
            if (env.password) { 
                password = env.password 
            } 
        } 
    } 

    def dataSources = [:] 
    Environment.list().each {env -> 
        dataSources[env.id] = ref(env.prefix + 'DataSource') 
    } 

    dataSource(SwitchableDataSource) { 
        targetDataSources = dataSources 
    } 
}

Environment currently uses a static list to hold the environment config. This could be done better via a reloadable properties file or by adding a view/controller to modify the environment settings on the fly. Environment.groovy:

package com.leebutts

class Environment {

    static environments = []

    static {
        environments << [id: 1, name: 'local', prefix: 'local', 
                          host: 'localhost']
        environments << [id: 2, name: 'UAT', prefix: 'uat',
                            host: 'uat.leebutts.com']
        environments << [id: 3, name: 'Testing', prefix: 'testing',
                         host: 'testing.leebutts.com'] 
        environments << [id: 4, name: 'Beta', prefix: 'beta',
                         host: 'beta.leebutts.com', 
                         passwordRequired: true] 
        environments << [id: 5, name: 'Prod', prefix: 'prod', 
                         host: 'db.leebutts.com', user:'grails', 
                         port: 13306, 
                         passwordRequired: true] 

        //unique id check 
        environments.each {env ->
            assert environments
                .findAll {it.id == env.id}.size() == 1}
    }

    static list() {
        return environments
    }
}

SwitchableDataSource needs a way to determine which environment the current request wishes to use. It does this via a ThreadLocal holder EnvironmentHolder.groovy:

package com.leebutts

class EnvironmentHolder {

    private static final ThreadLocal contextHolder
                                = new ThreadLocal();

    static void setEnvironment(Map environment) {
        contextHolder.set(environment);
    }

    static getEnvironment() {
        return contextHolder.get();
    }

    static void clear() {
        contextHolder.remove();
    }
}

Now that the infrastructure is in place, the next step is to add a controller to allow users to select the environment they wish to use and a filter to set a default environment if one has not yet been chosen. The controller is called via ajax (in my application) but could be used as a standard controller just as easily. It looks up the Environment based on an ID and then tests the connection to make sure the password supplied is valid (if a password is required as specified in the environment config). If a password is being used it takes a copy of the environment config map, adds the password and stores it in the session so that the user doesn't have to re-enter the password on every screen and so that only this user has access to the password. EnvironmentController.groovy:

import com.leebutts.Environment
import com.leebutts.EnvironmentHolder
import javax.servlet.http.HttpServletResponse
import org.codehaus.groovy.grails.commons.ApplicationAttributes
import org.codehaus.groovy.grails.web.context.ServletContextHolder

class EnvironmentController {

    def change = {
        if (params.environment) {
            def env = Environment.list()
                     .find {it.id == new Integer(params.environment)}
            if (env) {
                if (env.passwordRequired) {
                    if (params.password) {
                        //take a copy and add a pword
                        env = addPasswordToEnvCopy(params, env)
                    } else {
                        render 'PASSWORD REQUIRED'
                        response.setStatus(
                          HttpServletResponse.SC_UNAUTHORIZED)
                        return
                    }
                }

                //test connection
                def oldEnv = EnvironmentHolder.getEnvironment()
                EnvironmentHolder.setEnvironment env
                def ds = getDataSourceForEnv()
                try {
                    def con = ds.getConnection()
                    session.environment = env
                    render 'Environment change complete.'
                } catch (e) {
                    EnvironmentHolder.setEnvironment oldEnv
                    render 'Unable to connect to database: '
                              + e.message
                    response.setStatus(
                       HttpServletResponse.SC_UNAUTHORIZED)
                    return
                }
            } else {
                render 'No such environment'
                response.setStatus(
                        HttpServletResponse.SC_BAD_REQUEST)
            }
        } else {
            render 'Missing parameter environment'
            response.setStatus(HttpServletResponse.SC_BAD_REQUEST)
        }
    }

    private def getDataSourceForEnv() {
        def servletContext = ServletContextHolder.servletContext
        def ctx = servletContext
                    .getAttribute(
                         ApplicationAttributes.APPLICATION_CONTEXT)
        return ctx.dataSource
    }

    private Map addPasswordToEnvCopy(Map params, env) {
        def myEnv = [:]
        env.each {key, val ->
            myEnv[key] = val
        }
        myEnv.password = params.password
        return myEnv
    }
}

As mentioned, there is also a simple filter for defaulting the environment to the first one in the list if one has not been selected and storing it in the ThreadLocal holder. Filters.groovy:

import com.leebutts.EnvironmentHolder
import com.leebutts.Environment

class Filters {
    def filters = {
        all(uri: '/**') {
            before = {
                if (!session.environment) {
                    session.environment = Environment.list()[0]
                }
                EnvironmentHolder.setEnvironment(session.environment)
            }
        }
    }
}

The final step is to add an environment selection form to your layout so that users can choose their environment. views/layouts/main.gsp:

<html>
<head>
    <title>Administration System</title>
    <link rel="stylesheet"
            href="${createLinkTo(dir: 'css', file: 'main.css')}"/>
    <g:layoutHead/>
    <g:javascript library="application"/>
    <g:javascript library="prototype"/>
    <script type="text/javascript">
        function refresh()
        {
            window.location.reload(false);
        }

        function loading() {
            document.getElementById('spinner').style.display = 'inline';
            document.getElementById('error').style.display = 'none';
        }
      
        function showError(e) {
            var errorDiv = document.getElementById('error')
            errorDiv.innerHTML = '<ul><li>'
                     + e.responseText + '</li></ul>';
            errorDiv.style.display = 'block';
        }
    </script>
</head>
<body>
<div class="logo">
    <div style="margin-left:10px;">
        <h1>Current Environment: 
               ${session.environment?.name ?: 'None'}</h1>
        <form action="">
            <g:select name="environment" 
                   from="${com.leebutts.Environment.list()}" 
                      optionKey="id" optionValue="name" 
                       value="${session.environment?.id}"/>
            <g:passwordField name="password"/>
            <g:submitToRemote value="Select" controller="environment" 
             action="change" update="currentEnv"
             onLoading="loading();"
             onComplete
               ="document.getElementById('spinner').style.display='none';"
             onFailure="showError(e)"
             onSuccess="refresh()"/> <br/>
            <div class="errors" id="error" 
              style="display:none;width:500px;">

            </div>
            <img id="spinner" style="display:none;"
              src="${createLinkTo(dir: 'images', file: 'spinner.gif')}"
              alt="Spinner"/>
        </form>
    </div>
</div>
<g:layoutBody/>
</body>
</html>

The finished screen looks something like this:







As this is an internal admin application it has not been tested as thoroughly as standard prod code so please do so before using it in a "live" application. Please post any corrections/bug fixes.

Drag racing photos

I found some "official" of me at Willow bank the other day

Unreal 3D Car Art

I think this is the best CG car art I've ever seen! Deviant art gallery: http://dangeruss.deviantart.com Article about him here: http://www.nextautos.com/sexy-digital-sheetmetal-the-art-dangeruss

New PB at Willowbank yesterday

I went out to Willowbank Raceway yesterday for some 1/4 mile fun. My best time was 13.791, about 1/2 a second quicker than last time thanks to a new exhaust, front mount intercooler and clutch.

I haven't found any video of my runs but here's some I took of the other VR-4s and Evos that were there. The last clip is of an R35 GT-R which ran an 11.3!