dbsmoketest

Some simple example tasks for using Gradle to smoke test databases.

Installing

I suggest simply sticking these in the buildSrc directory of your Gradle project.

Using

There's an example of using the H2 database in example.gradle, but it's small enough to give in full:

import com.github.jlmelville.dbsmoketest.H2SmokeTest

task checkDb(type: H2SmokeTest) {
    url = "jdbc:h2:~/test;IFEXISTS=TRUE"
    username = "sa"
    password = ""
    driverRepo = "https://repo1.maven.org/maven2/"
    errorMessage = "DB doesn't seem to be up"
    stopBuildOnFailure = false
}

If you can install H2 and get as far as logging in the quickstart guide, then you should be able to successfully smoke test the test DB with:

gradle -b example.gradle checkDb

There are classes for Oracle and Postgres too, so it should be enough to give the general idea. The stopBuildOnFailure flag is useful if you're running this in Jenkins, when the build failing will normally prevent the logs getting archived.

Why?

In his excellent book Gradle in Action, Benjamin Muschko provides some useful tasks for smoke testing web apps via HTTP. You can extend these ideas quite easily to smoke testing a database by connecting via JDBC and then executing a simple query.

What makes this a bit trickier is that you need to make sure that the JDBC drivers get loaded at the correct time. A straightforward solution is to add the following to your build.gradle whenever you want to load a JDBC driver:

repositories {
    maven {
       // ...
    }
}

configurations {
    jdbcdriver
}

dependencies {
    jdbcdriver 'oracle:ojdbc6:11.2.0.4'
}

task smokeTest {
    configurations.jdbcdriver.files.each {
        Sql.classLoader.addURL it.toURI().toURL()
    }

    // This is the only bit that does anything task-like
    Sql.withInstance(url, username, password, driver) { sql ->
        sql.execute 'select sysdate from dual'
    }
}

Quite a palaver, just to load a JDBC driver. The usual way to tidy things up by writing a custom task only cleans up the Sql stuff in the smokeTest task. You can't just copy and paste the repositories, configurations and dependencies blocks into the buildSrc build.gradle, because they need to be loaded when the task gets run, not when it's built. So you would need to keep them littering your build script, and now there's not even anything terribly obvious to indicate why they're there.

My solution was to eschew the declarative approach and use the Gradle API to load things from a method in the custom task. This was originally just a gist, but there are just enough moving parts that I don't know if anyone could reproduce this from just some snippet of codes. Hence this project.

Thanks

This is based heavily on the material in Chapter 15 of Gradle in Action. Author Benjamin Muschko kindly got in touch with Manning to explicitly apply a license to the source code for the book so I could publish this without fear of infringing copyright. Obviously, the horrific quality of the code in these tasks is not a reflection on the material in the book.

License

The MIT License.