Web3j Solidity Gradle Plugin¶

Simple Gradle plugin used by the Web3j plugin to compile Solidity contracts, but it can be used in any standalone project for this purpose.

Plugin configuration¶

To configure the Web3j Solidity Gradle Plugin using the plugins DSL or the legacy plugin application, check the plugin page. The minimum Gradle version to run the plugin is 7.+.

Then run this command from your project containing Solidity contracts:

./gradlew build

After the task execution, the base directory for compiled code (by default $buildDir/resources/solidity) will contain a directory for each source set (by default main and test), and each of those a directory with the compiled code.

Code generation¶

The solidity DSL allows to configure the generated code, e.g.:

solidity {
    outputComponents = [BIN, ABI, ASM_JSON]
    optimizeRuns = 500
}

The properties accepted by the DSL are listed in the following table:

Name	Type	Default value	Description
`executable`	`String`	`null` (bundled with the plugin)	Solidity compiler path.
`version`	`String`	`null` (defined by contract's pragma)	Solidity compiler version.
`overwrite`	`Boolean`	`true`	Overwrite existing files.
`resolvePackages`	`Boolean`	`true`	Resolve third-party contract packages.
`optimize`	`Boolean`	`true`	Enable byte code optimizer.
`optimizeRuns`	`Integer`	`200`	Set for how many contract runs to optimize.
`prettyJson`	`Boolean`	`false`	Output JSON in pretty format. Enables the combined JSON output.
`ignoreMissing`	`Boolean`	`false`	Ignore missing files.
`allowPaths`	`List<String>`	`['src/main/solidity', 'src/test/solidity', ...]`	Allow a given path for imports.
`pathRemappings`	`Map<String, String>`	`[ : ]`	Remaps contract imports to target path.
`packages`	`Map<String, String>`	`[ : ]`	Additional npm packages (name to version) to resolve.
`evmVersion`	`EVMVersion`	`BYZANTIUM`	Select desired EVM version.
`outputComponents`	`OutputComponent[]`	`[BIN, ABI]`	List of output components to produce.
`combinedOutputComponents`	`CombinedOutputComponent[]`	`[BIN, BIN_RUNTIME, SRCMAP, SRCMAP_RUNTIME]`	List of output components in combined JSON output.

Notes:

Setting the executable property will disable the bundled solc and use your local or containerized executable:

solidity {
    executable = "docker run --rm -v $projectDir/src:/src -v $projectDir/build:/build ethereum/solc:0.6.4-alpine"
    version = '0.4.15'
}

Use version to change the bundled Solidity version. Check the Solidity releases for all available versions.
allowPaths contains all project's Solidity source sets by default.

Source sets¶

By default, all .sol files in $projectDir/src/main/solidity and $projectDir/src/test/solidity will be processed by the plugin. To specify and add different source sets, use the sourceSets DSL. You can also set your preferred output directory for compiled code.

sourceSets {
    main {
        solidity {
            srcDir 'my/custom/path/to/solidity'
            output.resourcesDir = file('out/bin/compiledSol')
        }
    }
}

Now with solidity gradle plugin version 0.4.2, you can set different solidity versions, evmVersions, optimize flag, optimizeRuns and ignoreMissing flag values for different sourceSets.

sourceSets {
    main {
        solidity {
            srcDir 'my/custom/path/to/solidity'
            output.resourcesDir = file('out/bin/compiledSol')
            evmVersion = 'ISTANBUL'
            optimize = true
            optimizeRuns = 200
            version = '0.8.12'
        }
    }
}

For Kotlin DSL, configure the source path with srcDir("my/custom/path/to/solidity"). The allowPaths property controls Solidity import resolution only; it does not replace source directories.

Gradle Node Plugin¶

The plugin makes use of the Node plugin to resolve third-party contract dependencies. It currently supports:

When importing libraries from @openzeppelin/contracts in your Solidity contract, the plugin will use the task resolveSolidity to generate a package.json file required by the Node plugin.

By default, package.json will be generated under the build/ directory. If you wish to change the directory for the Node plugin, add the following snippet to your build.gradle file:

node {
    nodeProjectDir = file("my/custom/node/directory")
}

The plugin will look for the package.json file in the directory set and will also download the node modules under the same directory.

Note: In case of problems with the package.json file, you can delete it, and it will be regenerated with the latest versions.

Resolving additional packages¶

Only scoped imports (e.g. @openzeppelin/contracts) written directly in your .sol files are detected automatically, and they are always resolved at their latest version. Use the packages property to declare extra npm packages that are not detected automatically, or to pin a specific version:

solidity {
    packages = [
        '@consensys-software/permissioning-smart-contracts': 'latest',
        '@uniswap/v3-core'                                 : '1.0.1'
    ]
}

Declared packages are added to the generated package.json, installed by npm and remapped automatically, so there is no need to disable resolvePackages or configure pathRemappings manually. A version declared here takes precedence over a version detected from imports.

Plugin tasks¶

The Java Plugin adds tasks to your project build using a naming convention on a per source set basis (i.e. compileJava, compileTestJava).

Similarly, the Solidity plugin will add a:

resolveSolidity task for all project Solidity sources.
compileSolidity task for the project main source set.
compile<SourceSet>Solidity for each remaining source set. (e.g. compileTestSolidity for the test source set, etc.).

To obtain a list and description of all added tasks, run the command:

./gradlew tasks --all