# Source attribute in a \`packer\` block

**URL:** <https://discuss.hashicorp.com/t/source-attribute-in-a-packer-block/54861>\
**Category:** Packer\
**Created:** [June 12, 2023, 12:38am UTC](https://discuss.hashicorp.com/t/source-attribute-in-a-packer-block/54861 "2023-06-12T00:38:23Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![pjmattingly](https://sea2.discourse-cdn.com/hashicorp/user_avatar/discuss.hashicorp.com/pjmattingly/32/36214_2.png) [@pjmattingly](https://discuss.hashicorp.com/u/pjmattingly)\
**Post date:** [June 12, 2023, 12:38am UTC](https://discuss.hashicorp.com/t/source-attribute-in-a-packer-block/54861/1 "2023-06-12T00:38:23Z")

</div>

Hello,

I’m starting to use Packer. I’m working through the tutorial (see: [Install Packer | Packer | HashiCorp Developer](https://developer.hashicorp.com/packer/tutorials/docker-get-started/get-started-install-cli)). The tutorial contains a sample template. The template include this block:

```auto
packer {
  required_plugins {
    docker = {
      version = ">= 0.0.7"
      source = "github.com/hashicorp/docker"
    }
  }
}

```

In this block the docker plugin is configured with a `source` attribute. Farther down the tutorial ask me not to worry about it:

```auto
The source attribute is only necessary when requiring a plugin outside the HashiCorp domain. You can find the full list of HashiCorp and community maintained builders plugins in the Packer Builders documentation page.

```

But, I would like to know what it is. Its value is `github.com/hashicorp/docker`, which looks like a URL, but is not. I’m assuming its some sort of namespace? This string isn’t mentioned in the documentation for the plugin. What is it for? If, in the future, I need a value for a `source` attribute, where could I find it?

---

<div class="post-metadata">

**Author:** ![mloskot](https://sea2.discourse-cdn.com/hashicorp/user_avatar/discuss.hashicorp.com/mloskot/32/11714_2.png) [@mloskot](https://discuss.hashicorp.com/u/mloskot)\
**Post date:** [June 12, 2023, 3:09pm UTC](https://discuss.hashicorp.com/t/source-attribute-in-a-packer-block/54861/2 "2023-06-12T15:09:00Z")

</div>

> [@pjmattingly](#):
>
> ```auto
> source = "github.com/hashicorp/docker"
> 
> ```

AFAIU, this is a (artificial) namespace indeed and it is mainly used to distinguish HashiCorp-curated plugins from all other plugins. At [packer init - Commands | Packer | HashiCorp Developer](https://developer.hashicorp.com/packer/docs/commands/init) you can read this explanation:

> HashiCorp does not officially verify third party Packer plugins, plugins not under the HashiCorp namespace `hashicorp/*`

which, IMO, should be dead explicit:

> not under the HashiCorp namespace `github.com/hashicorp/*`