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dagger/docs/learn/1010-dev-cue-package.md
Jean-Yves Gastaud 7ad5f264e6 docs: make dev-cue-package example naming consitant
Signed-off-by: Jean-Yves Gastaud <jygastaud@gmail.com>
Signed-off-by: Sam Alba <samalba@users.noreply.github.com>
2021-12-14 16:08:20 -08:00

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---
slug: /1010/dev-cue-package/
---
# Develop a new CUE package for Dagger
This tutorial illustrates how to create new packages, manually distribute them among your applications and contribute to the Dagger stdlib packages.
## Creating your package
### Initializing project
Create an empty directory for your new Dagger project:
```shell
mkdir project
cd project
```
As described in the previous tutorials, initialize your Dagger project:
```shell
dagger init
```
That will create two directories: `.dagger` and `cue.mod`, where our package will reside:
```shell
.
├── cue.mod
│ ├── module.cue
│ ├── pkg
│ └── usr
├── .dagger
│ └── env
```
### Writing the package
Now that you've initialized your project, it's time to write a simple package. Package name usually starts with a
domain name (as in Go) followed by a descriptive name. In this example, we reuse the Cloud Run example and create a
package from it.
```shell
mkdir -p cue.mod/pkg/github.com/username/gcpcloudrun
```
Let's write the package logic. It is basically what we've seen in the 106-cloudrun example:
```shell
touch cue.mod/pkg/github.com/username/gcpcloudrun/source.cue
```
```cue file=./tests/dev-cue-package/source.cue title="cue.mod/pkg/github.com/username/gcpcloudrun/source.cue"
```
### Running the package
Now that you've successfully created a package let's run it in a new environment. Create a new test package using
our reusable `gcpcloudrun`:
```cue file=./tests/dev-cue-package/script.sh#L3-L16
```
Run it:
```shell
dagger up -e staging
```
You should see a familiar output:
```shell
9:32AM ERR system | required input is missing input=run.src
9:32AM ERR system | required input is missing input=run.imageRef
9:32AM ERR system | required input is missing input=run.gcpConfig.region
9:32AM ERR system | required input is missing input=run.gcpConfig.project
9:32AM ERR system | required input is missing input=run.gcpConfig.serviceKey
9:32AM ERR system | required input is missing input=run.deploy.name
9:32AM FTL system | some required inputs are not set, please re-run with `--force` if you think it's a mistake missing=0s
```
## Manually distributing packages
You've probably guessed this package isn't tied to just your project. You can easily copy/paste it into any number
of different projects and use it as we've shown above.
```shell
mkdir -p /my-new-workspace/cue.mod/pkg/github.com/username/gcpcloudrun
cp ./cue.mod/pkg/github.com/username/gcpcloudrun/source.cue /new-workspace/cue.mod/pkg/github.com/username/gcpcloudrun
```
## Contributing to Dagger stdlib
Our [stdlib](https://github.com/dagger/dagger/tree/main/stdlib) has many valuable packages that you can use.
You've probably seen it when you've initialized your project:
```shell
.
├── cue.mod
│ ├── module.cue
│ ├── pkg
│ │ ├── alpha.dagger.io
│ │ └── .gitignore
│ └── usr
```
We are still a small community and are constantly looking for new contributors that will work with us to improve this fantastic project. If you feel like we are missing a package or want to improve an existing one, please start with our
[contributing docs](https://github.com/dagger/dagger/blob/main/CONTRIBUTING.md) and open a PR.