CODEWITHSUNDEEP
phingfallback
Mitch Hen Chez
Mitch Hen Chez

Reputation: 21

Phing property: fallback from environment variable to property file

Is there an elegant way of determining a value for a property? For example, I'd like to allow a property to be read from a file, but also to be grabbed from an environment variable. If the environment variable is present, I'd like to prioritize it over the file's value.

Here's what I have (with the example property deploy.destination):

<property environment="env" />
<if>
    <isset property="env.DEPLOY_DEST" />
    <then>
        <property name="deploy.destination" refid="env.DEPLOY_DEST"/>
    </then>
</if>
<property file="build.properties"/>

However, it's fairly bulky (especially for more than more property).

Is there a way I can do something like this?

<property environment="env" />
<property name="deploy.destination" refid="env.DEPLOY_DEST"/>
<property file="build.properties"/>

With this example, it fails if env.DEPLOY_DEST is not set.

Thanks!

Upvotes: 1

Views: 1178

Answers (2)

jawira
jawira

Reputation: 4598

Environment variables are widely used in CI/CD platforms, if this is your case maybe the following will be useful.

First I show you my buildfile build.xml:

<project name="Demo" default="deployment">

    <target name="deployment">
        <property file="build.properties.ini"/>
        <echo message="Your host is: ${destination}"/>
    </target>

</project>

My propertyfile build.properties.ini:

destination = localhost

If we execute the only target in our buildfile, $ phing deployment, the output will be the expected one:

$ phing deployment
[echo] Your host is: localhost

Now execute the following $ phing deployment -Ddestination=example.com, the output is:

$ phing deployment -Ddestination=example.com
[echo] Your host is: example.com

As you can see my buildfile and propertyfile remain unchanged. however I was capable change the value of destination property, this is because when properties are set as a command line argument they have higher priority than properties declared in a property file.

To conclude:

// Use the following in development
$ phing deployment

// And override "destination" in your CI/CD config
$ phing deployment -Ddestination=$DEPLOY_DEST

Source: https://www.phing.info/phing/guide/en/output/chunkhtml/ch04s03.html

Upvotes: 1

one-mb
one-mb

Reputation: 39

Given your statement:

If the environment variable is present, I'd like to prioritize it over the file's value.

you can do

<property environment="env" />
<if>
    <available file="custom.properties"/>
    <then>
        <property file="custom.properties" override="false"/>
    </then>
</if>

The key shall be override="false" to allow env property values to stay.

Upvotes: 2

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