Categorygithub.com/hashicorp/packer-plugin-sdk

# README

Go Reference

Packer Plugin SDK

This SDK enables building Packer plugins. This allows Packer's users to use both the officially-supported builders, provisioners, and post-processors, and custom in-house solutions.

Packer itself is a tool for building identical machine images for multiple platforms from a single source configuration. You can find more about Packer on its website and its GitHub repository.

Packer CLI Compatibility

Packer v1.7.0 or later is needed for this SDK. Versions of Packer prior to that release are still compatible with third-party plugins, but the plugins should use the plugin tooling from inside earlier versions of Packer to ensure complete API compatibility.

Go Compatibility

The Packer Plugin SDK is built in Go, and uses the support policy of Go as its support policy. The two latest major releases of Go are supported by the SDK.

Currently, that means Go 1.14 or later must be used when building a provider with the SDK.

Getting Started

See the Extending Packer docs for a guided tour of plugin development.

Documentation

See the Extending Packer section on the Packer website.

Testing

The SDK embeds tests to ensure we don't introduce a regression in the future. Up to version 0.5.0 of the SDK, tests would be runnable with make test on their own but since we removed the replace statement for go-cty tests won't work out-of-the-box. Users will need to invoke packer-sdc fix . in order to fix the go.mod and go.sum files before running tests. Please do not commit these changes, as adding this replace section to the go.mod file will make it impossible for dependents to run go install for packer-sdc afterwards.

Packer Scope (Plugins VS Core)

Packer Core

  • acts as an RPC client
  • interacts with the user
  • parses (HCL/JSON) configuration
  • manages build as whole, asks plugin(s) to manage the image lifecycle and modify the image being built.
  • discovers plugin(s) and their versions per configuration
  • manages plugin lifecycles (i.e. spins up & tears down plugin process)
  • passes relevant parts of parsed (valid JSON/HCL) and interpolated configuration to plugin(s)

Packer Provider (via this SDK)

  • acts as RPC server
  • executes any domain-specific logic based on received parsed configuration. For builders this includes managing the vm lifecycle on a give hypervisor or cloud; for provisioners this involves calling the operation on the remote instance.
  • tests domain-specific logic via provided acceptance test framework
  • provides Core with template validation, artifact information, and information about whether the plugin process succeeded or failed.

Migrating to SDK from built-in SDK

Migrating to the standalone SDK v1 is covered on the Plugin SDK section of the website.

Versioning

The Packer Plugin SDK is a Go module versioned using semantic versioning.

Contributing

See .github/CONTRIBUTING.md

License

Mozilla Public License v2.0

# Packages

Package acctest provides an acceptance testing framework for testing builders and provisioners.
Package adapter helps command line tools connect to the guest via a Packer communicator.
Package bootcommand generates and sends boot commands to the remote instance.
Package chroot provides convenience tooling specific to chroot builders.
No description provided by the author
Package common provides the PackerConfig structure that gets passed to every plugin and contains information populated by the Packer core.
Package communicator provides common steps for connecting to an instance using the Packer communicator.
No description provided by the author
Package filelock makes it easy to create and check file locks for concurrent processes.
Package guestexec provides a shim for running common operating system commands on the guest/remote instance that is being provisioned.
Package hcl2helper provides helper functions for parsing or getting hcl2 types to and from a Packer plugin config.
No description provided by the author
multistep is a library for building up complex actions using individual, discrete steps.
Package net contains some helper wrapping functions for the http and net golang libraries that meet Packer-specific needs.
go:generate packer-sdc mapstructure-to-hcl2 -type MockProvisioner.
Package packerbuilderdata provides tooling for setting and getting special builder-generated data that will be passed to the provisioners.
Package pathing determines where to put the Packer config directory based on host OS architecture and user environment variables.
The plugin package provides the functionality to both expose a Packer plugin binary and to connect to an existing Packer plugin binary.
Package random is a helper for generating random alphanumeric strings.
Package retry provides tooling to retry API calls which are known to be vulnerable to throttling or flakiness due to eventual consistency.
Package rpc contains the implementation of the remote procedure call code that the Packer core uses to communicate with packer plugins.
No description provided by the author
Package shell defines configuration fields that are common to many different kinds of shell.
No description provided by the author
Package shutdowncommand is a helper module for builder plugin configuration.
Package template helps plugins parse the Packer template into golang structures.
Package tmp provides temporary directory helpers.
Package useragent creates a user agent for builders to use when calling out to cloud APIs or other addresses.
Package uuid provides helper functions for creating time-ordered UUIDs.
Package version helps plugin creators set and track the plugin version using the same convenience functions used by the Packer core.