Checksum Post-Processor

Type: checksum

The checksum post-processor computes specified checksum for the artifact list from an upstream builder or post-processor. All downstream post-processors will see the new artifacts. The primary use-case is compute checksum for artifact to verify it later.

After computes checksum for artifacts, you can use new artifacts with other post-processors like artifice, compress, docker-push, or a third-party post-processor.

Basic example

{
  "type": "checksum",
  "checksum_types": ["sha1", "sha256"],
  "output": "packer_{{.BuildName}}_{{.ChecksumType}}.checksum"
}

post-processor "checksum" {
  checksum_types = ["sha1", "sha256"]
  output = "packer_{{.BuildName}}_{{.ChecksumType}}.checksum"
}

Configuration Reference

Optional parameters:

• checksum_types (array of strings) - An array of strings of checksum types to compute. If empty, Defaults to md5. Allowed values are:

  • md5
  • sha1
  • sha224
  • sha256
  • sha384
  • sha512

• output (string) - Specify filename to store checksums. This defaults to packer_{{.BuildName}}_{{.BuilderType}}_{{.ChecksumType}}.checksum. For example, if you had a builder named database, you might see the file written as packer_database_docker_md5.checksum. This is treated as a template engine. Therefore, you may use user variables and template functions in this field. The following special variables are also available to use in the output template:

  • BuildName: The name of the builder that produced the artifact.
  • BuilderType: The type of builder used to produce the artifact.
  • ChecksumType: The type of checksums the file contains. This should be used if you have more than one value in checksum_types.