packer-cn/website/content/docs/plugins/index.mdx

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---
description: |
Packer Plugins allow new functionality to be added to Packer without modifying
the core source code. Packer plugins are able to add new builders,
provisioners, hooks, and more.
page_title: Plugins
sidebar_title: Packer Plugins
---
# Packer Plugins
Packer Plugins allow new functionality to be added to Packer without modifying
the core source code. Packer plugins are able to add new components to Packer,
such as builders, provisioners, post-processors, and data sources.
This page documents how to install plugins.
If you're interested in developing plugins, see the [developing
plugins](/docs/plugins/creation#developing-plugins) page.
The current official listing of community-written plugins can be found
[here](/community-tools#third-party-plugins); if you have written a Packer
plugin, please reach out to us so we can add your plugin to the website.
## How Plugins Work
Packer plugins are completely separate, standalone applications that the core
of Packer starts and communicates with. Even the components that ship with the
Packer core (core builders, provisioners, and post-processors) are implemented
in a similar way and run as though they are standalone plugins.
These plugin applications aren't meant to be run manually. Instead, Packer core
launches and communicates with them. The next time you run a Packer build,
look at your process list and you should see a handful of `packer-` prefixed
applications running. One of those applications is the core; the rest are
plugins -- one plugin process is launched for each component used in a Packer
build.
## Installing Plugins
Currently, you do not need to install plugins for builder, provisioner, or
post-processor components documented on the Packer website; these components
ship with the Packer core and Packer automatically knows how to find and launch
them. These instructions are for installing custom components that are not
bundled with the Packer core.
The below tabs reference "multi-component" and "single-component" plugins. If
you are not sure what kind of plugin you are trying to install, the easiest way
to find out is to check the name. If the name starts with `packer-plugin-`, then
it is a multi-component plugin. If the name starts with a prefix that actually
says the component type (e.g. `packer-provisioner-` or `packer-builder`), then
it is a single-component plugin.
<Tabs>
<Tab heading="Packer init (from Packer v1.7.0)">
~> **Note**: Only _multi-component plugin binaries_ -- that is plugins named
packer-plugin-*, like the `packer-plugin-amazon` -- are expected to work with
Packer init. The legacy `builder`, `post-processor` and `provisioner` plugin
types will keep on being detected but Packer cannot install them automatically.
If a plugin you use has not been upgraded to use the multi-component plugin
architecture, contact your maintainer to request an upgrade.
### Create a required_plugins block
1. Add a
[`required_plugins`](/docs/templates/hcl_templates/blocks/packer#specifying-plugin-requirements)
block to your [packer block](/docs/templates/hcl_templates/blocks/packer). Each block will tell Packer what version(s) of a
particular plugin can be installed. Make sure to set a valid [version
constraint string](/docs/templates/hcl_templates/blocks/packer#version-constraints).
Here is an example `required_plugins` block:
```hcl
packer {
required_plugins {
myawesomecloud = {
version = ">= 2.7.0"
source = "github.com/azr/myawesomecloud"
}
happycloud = {
version = ">= 1.1.3"
source = "github.com/azr/happycloud"
}
}
}
```
2. Run [`packer init`](/docs/commands/init) from your project directory (the
directory containing your Packer templates) to install all missing plugin
binaries. Given the above example, Packer will try to look for a GitHub
repository owned by user or organization `azr` named
`packer-plugin-myawesomecloud` and `packer-plugin-happycloud`.
## Names and Addresses
Each plugin has two identifiers:
* A `source` address, which is only necessary when requiring a plugin outside the HashiCorp domain.
* A unique **local name**, which is used everywhere else in a Packer
configuration.
### Local Names
Local names allow you to access the components of a plugin and must be unique
per configuration.
This is best explained using an example. In the above `required_plugins` block,
we declared the local name "myawesomecloud" for the plugin `azr/myawesomecloud`.
If the "myawesomecloud" plugin contains both an "ebs" builder and an "import"
post-processor, then the builder will be accessed in a source block by using:
```hcl
source "myawesomecloud-ebs" "example" {
// builder configuration...
}
```
similarly, the import post-processor would be accessed by declaring the
post-processor block:
```hcl
post-processor "myawesomecloud-import" {
// post-processor configuration...
}
```
If we change the required_plugins block to use a different local name "foo":
```hcl
required_plugins {
foo = {
version = ">= 2.7.0"
source = "github.com/azr/myawesomecloud"
}
}
```
Then we'd instead access that builder using the source:
```hcl
source "foo-ebs" "example" {
// builder configuration...
}
```
## Source Addresses
A plugin's source address is its global identifier. It also tells Packer where
to download it.
Source addresses consist of three parts delimited by slashes (`/`), as
follows:
`<HOSTNAME>/<NAMESPACE>/<TYPE>`
* **Hostname:** The hostname of the location/service that
distributes the plugin. Currently, the only valid "hostname" is github.com,
but we plan to eventually support plugins downloaded from other domains.
* **Namespace:** An organizational namespace within the specified host.
This often is the organization that publishes the plugin.
* **Type:** A short name for the platform or system the plugin manages. The
type is usually the plugin's preferred local name.
For example, the fictional `myawesomecloud` plugin could belong to the
`hashicorp` namespace on `github.com`, so its `source` could be
`github.com/hashicorp/myawesomecloud`,
Note: the actual _repository_ that myawesomecloud comes from must always have
the name format `github.com/hashicorp/packer-plugin-myawesomecloud`, but the
`required_plugins` block omits the redundant `packer-plugin-` repository prefix
for brevity.
The source address with all three components given explicitly is called the
plugin's _fully-qualified address_. You will see fully-qualified address in
various outputs, like error messages.
## Plugin location
@include "plugins/plugin-location.mdx"
## Implicit Github urls
Using the following example :
```hcl
required_plugins {
happycloud = {
version = ">= 2.7.0"
source = "github.com/azr/happycloud"
}
}
```
The plugin getter will look for plugins located at:
* github.com/azr/packer-plugin-happycloud
Packer will error if you set the `packer-plugin-` prefix in a `source`. This
will avoid conflicting with other plugins for other tools, like Terraform.
</Tab>
<Tab heading="manually (multi-component plugin)">
The easiest way to manually install a plugin is to name it correctly, then place
it in the proper directory. To name a plugin correctly, make sure the binary is
named `packer-plugin-NAME`. For example, `packer-plugin-amazon` for a "plugin"
binary named "amazon". This binary will make one or more plugins available to
use. Valid types for plugins are down this page.
Once the plugin is named properly, Packer automatically discovers plugins in
the following directories in the given order. If a conflicting plugin is found
later, it will take precedence over one found earlier.
1. The directory where `packer` is, or the executable directory.
2. The `$HOME/.packer.d/plugins` directory, if `$HOME` is defined (unix)
3. The `%APPDATA%/packer.d/plugins` if `%APPDATA%` is defined (windows)
4. The `%USERPROFILE%/packer.d/plugins` if `%USERPROFILE%` is defined
(windows)
5. The current working directory.
6. The directory defined in the env var `PACKER_PLUGIN_PATH`. There can be more
than one directory defined; for example, `~/custom-dir-1:~/custom-dir-2`.
Separate directories in the PATH string using a colon (`:`) on posix systems and
a semicolon (`;`) on windows systems. The above example path would be able to
find a provisioner named `packer-provisioner-foo` in either
`~/custom-dir-1/packer-provisioner-foo` or
`~/custom-dir-2/packer-provisioner-foo`.
The valid types for plugins are:
- `plugin` - A plugin binary that can contain one or more of each Packer plugin
type.
- `builder` - Plugins responsible for building images for a specific
platform.
- `post-processor` - A post-processor responsible for taking an artifact from
a builder and turning it into something else.
- `provisioner` - A provisioner to install software on images created by a
builder.
</Tab>
<Tab heading="manually (single-component plugin)">
</Tab>
</Tabs>