Gradle Properties - Runtime and Project Configuration
External
- https://docs.gradle.org/current/userguide/groovy_build_script_primer.html#groovy:properties
- https://docs.gradle.org/current/userguide/build_environment.html
Internal
TODO
Document the difference between properties and extra properties.
Overview
"Properties" in this context represent external configuration elements passed to a Gradle build to modify the behavior of the Gradle runtime itself, or the behavior of tasks being executed by various projects that are part of the build. Gradle supports many kinds of "properties": configuration can be passed as command line options, system properties, settings.gradle and build.gradle extra properties, gradle.properties file properties and environment variables. All these configuration elements are provided externally and injected into the build and various model object instances.
It is also possible to define properties, referred to as extra properties, in settings.gradle and build.gradle scripts and pass configuration around between different elements of the build.
Since build scripts may include executable code, it is also possible to use local variables, which are a feature of the underlying Groovy language.
The external configuration and extra properties become part of the state of various objects of the build, such as projects or tasks. The state of build objects can be read from settings.gradle or build.gradle scripts via dedicated accessors.
A project exposes project properties: coordinates such as name, group and version, various other state properties such as the description, path, and externally-configured project properties that come from gradle.properties file hierarchy or -P command line options. More details about accessing the project state and externally-configured properties are available in:
A task also exposes its state (name, description, whether it is enabled or not) through getters and DLS elements.
Property Syntax
Property Names
Property keys may contain dots or dashes, but if they do, special precautions should be taken. A property named "my.color" cannot be dereferenced using the simple format:
"color is ${project.my.color}"
Gradle will throw the following error message:
Could not get unknown property 'my' for project ':test' of type org.gradle.api.Project.
The property can still be retrieved, but only using project.property('...') method call:
"color is ${project.property('my.color')}"
Property Values
Declare the value without simple or double quotation marks, it will be handled as a string:
color = red
If simple or double quotation marks are used, they will be considered as part of the string and they will be used verbatim in ${...} dereferences:
"color ${color}"
will be rendered:
"color 'red'"
or
"color \"red\""