Traffic redirection to https in Grails behind load balancer

Grails security plugin has nice feature that allows automatically redirect queries for specific pages to https. For example, you can put this code into Config.groovy to redirect all requests:

grails.plugins.springsecurity.secureChannel.definition = [
    '/**':         'REQUIRES_SECURE_CHANNEL'
]

Unfortunately this does not work when your Tomcat is behind load balancer that does all encryption. To do it requires a little more work.

First, it is needed to specify how to detect either connection is secure or not. Standard way to do it with load balancers is to use X-Forwarded-Proto header. So it needs to be specified in Config.groovy like:

grails.plugins.springsecurity.secureChannel.useHeaderCheckChannelSecurity = true
grails.plugins.springsecurity.portMapper.httpsPort = 443

Worst part, is that it requires Tomcat reconfiguration, so it is needed to update Connector element in server.xml, like:

<Connector port="8080" protocol="HTTP/1.1" connectionTimeout="20000" redirectPort="8443"  proxyName="yourserver.com" proxyPort="443" secure="true" scheme="https"  />

Good part is that it works nicely locally and across multiple environments, no need for fake certificates or different builds.

Setting environment variables when running command via SSH in Ubuntu

There are less environment variables available when running command directly by SSH then interactively. This is because for some reason, Ubuntu does a little less for non-interactive shells and stops executing .bashrc after this line:

[ -z "$PS1" ] && return

So if you wish to run anything, it should be done before, like:

export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_21/
[ -z "$PS1" ] && return

Convert color console output into HTML with Java

Some command line tools can print colored text, which looks nice in console itself (if it is supported), but not so nice when you need to show it in HTML:

[47;32mhello world

There is small console tool "aha" that can pipe such input and transform it directly in command line, but sometimes you have to do it from code. For such cases there is Java library Jansi which prints ANSI escape sequences into Windows consoles. Their less advertised feature is library for direct conversion between ANSI and HTML, which it does just fine:

@Grapes(
    @Grab(group='org.fusesource.jansi', module='jansi', version='1.11')
)

import org.fusesource.jansi.*

private String colorize(String text) throws IOException {
  new ByteArrayOutputStream().with {
    new HtmlAnsiOutputStream(it).with {
      write(text.getBytes("UTF-8"))
      close()
    }
    return new String(it.toByteArray(), "UTF-8");
  }
}

println colorize(" [47;32mhello world")

Adding error messages to domain object in Grails

Sometimes it is more convenient to do some validation outside of the domain object, on the other side it is still nice to use standard error reporting facilities. For these cases, you can inject errors into domain objects like:

    if (someError) {
      domainobject.errors.rejectValue('param', "hasErrors")
    }
    ...
    if (!domainobject.hasErrors() && domainobject.save(flush: true)) {
    ...

Jenkins kills Tomcat or other Java process after job ends

Recently, I was adding new application deployment to Tomcat server that was started by Jenkins. Process was starting nicely, but was stopping at the end of the job. The only clue was log record:

Service exit with a return value of 143

This issue can be easily solved by adding -Xrs to JAVA_OPTS. Option description can be found at http://docs.oracle.com/javase/6/docs/technotes/tools/windows/java.html.

Running Selenium with Groovy on PhantomJS

There is script that runs and takes snapshot of PhantomJS with Selenium:

@Grab("com.github.detro.ghostdriver:phantomjsdriver:1.0.1")

import org.openqa.selenium.*
import org.openqa.selenium.phantomjs.PhantomJSDriver
import org.openqa.selenium.remote.DesiredCapabilities

new PhantomJSDriver(new DesiredCapabilities()).with {
    manage().window().setSize(new Dimension(1028, 768))
 get("http://www.google.com")
 getScreenshotAs(OutputType.FILE).renameTo("screenshot.png")
 quit()
}

Running Selenium with Groovy on Firefox

There is small script to run and take screenshot in Firefox with Selenium from Groovy:

@Grab("org.seleniumhq.selenium:selenium-firefox-driver:2.34.0")

import org.openqa.selenium.firefox.FirefoxDriver
import org.openqa.selenium.*
 
new FirefoxDriver().with {
 get("http://www.google.com")
 getScreenshotAs(OutputType.FILE).renameTo("screenshot.png")
 quit()
}