Dagger Module Init - Dagger

A new Dagger module is initialized by calling dagger init. This creates a new dagger.json configuration file in the current working directory, together with sample Dagger Function source code. The configuration file will default the name of the module to the current directory name, unless an alternative is specified with the --name argument.

Once a module is initialized, dagger develop --sdk=... sets up or updates all the resources needed to develop the module locally. By default, the module source code will be stored in the current working directory, unless an alternative is specified with the --source argument.

:::warning Running dagger develop regenerates the module's code based on dependencies, the current state of the module, and the current Dagger API version. This can result in unexpected results if there are significant changes between the previous and latest installed Dagger API versions. Always refer to the changelog for a complete list of changes (including breaking changes) in each Dagger release before running dagger develop, or use the --compat=skip option to bypass updating the Dagger API version. :::

The default template from dagger develop creates the following structure:

.
├── LICENSE
├── dagger.gen.go
├── go.mod
├── go.sum
├── internal
│   ├── dagger
│   ├── querybuilder
│   └── telemetry
└── main.go
└── dagger.json

In this structure:

dagger.json is the Dagger module configuration file.
go.mod/go.sum manage the Go module and its dependencies.
main.go is where your Dagger module code goes. It contains sample code to help you get started.
internal contains automatically-generated types and helpers needed to configure and run the module:
- dagger contains definitions for the Dagger API that's tied to the currently running Dagger Engine container.
- querybuilder has utilities for building GraphQL queries (used internally by the dagger package).
- telemetry has utilities for sending Dagger Engine telemetry.

For examples of modules written in Go, see Daggerverse Modules in Go.

</TabItem> <TabItem value="python" label="Python">

.
├── LICENSE
├── pyproject.toml
├── uv.lock
├── sdk
├── src
│   └── my_module
│       ├── __init__.py
│       └── main.py
└── dagger.json

In this structure:

dagger.json is the Dagger module configuration file.
pyproject.toml manages the Python project configuration.
uv.lock manages the module's pinned dependencies.
src/my_module/ is where your Dagger module code goes. It contains sample code to help you get started.
sdk/ contains the vendored Python SDK client library.

:::info Placing the source code under a src directory follows a common Python convention. To know more, see src layout vs flat layout. :::

For examples of modules written in Python, see Daggerverse Modules in Python.

</TabItem> <TabItem value="typescript" label="TypeScript">

.
├── LICENSE
├── package.json
├── sdk
├── src
│   └── index.ts
└── tsconfig.json
└── dagger.json

In this structure:

dagger.json is the Dagger module configuration file.
package.json manages the module dependencies.
src/ is where your Dagger module code goes. It contains sample code to help you get started.
sdk/ contains the bundled TypeScript SDK.

For examples of modules written in Typescript, see [Daggerverse Modules in Typescript](https://daggerverse.dev/search?sdk=typescript </TabItem> <TabItem value="php" label="PHP">

.
├── composer.json
├── composer.lock
├── dagger.json
├── LICENSE
├── README.md
├── sdk
├── src
│    └── MyModule.php
└── vendor

In this structure:

dagger.json is the Dagger module configuration file.
composer.json manages the module dependencies.
src/ is where your Dagger module code goes. It contains sample code to help you get started.
sdk/ contains the PHP SDK.

For examples of modules written in PHP, see Daggerverse Modules in PHP.

</TabItem> <TabItem value="java" label="Java"> ``` . ├── dagger.json ├── pom.xml ├── src │ └── main │ └── java │ └── io │ └── dagger │ └── modules │ └── mymodule │ ├── MyModule.java │ └── package-info.java └── target └── generated-sources ├── dagger-io ├── dagger-module └── entrypoint ```

In this structure:

dagger.json is the Dagger module configuration file.
pom.xml manages the module dependencies.
src/main/java/io/dagger/modules/mymodule/ is where your Dagger module code goes. It contains sample code to help you get started.
- MyModule.java is the main class that contains the Dagger Functions.
- package-info.java is the package information file and is the place to document the module.
target/generated-sources/ contains the generated Dagger code:
- dagger-io contains the Java specific library for Dagger.
- dagger-module contains all the types generated by Dagger and accessible from the module.
- entrypoint contains the generated entrypoint for the module.

The target folder is re-generated every time you run dagger develop and enables code completion and type hinting in the IDE.

The pom.xml is configured to automatically set the generated entrypoint as the main class so the generated JAR can be easily run. </TabItem> </Tabs>

:::note While you can use the utilities defined in the automatically-generated code above, you cannot edit these files. Even if you edit them locally, any changes will not be persisted when you run the module. :::