»The post-processor
block
Note: This page is about HCL2 Packer templates. HCL2 templates were first introduced as a beta feature into Packer version 1.5. As of v1.7, HCL2 support is no longer in beta, and is the preferred way to write Packer configuration. For the old-style stable configuration language see template docs. As of v1.6.2, you can convert your legacy JSON template into an HCL2 config file using the hcl2_upgrade command.
The post-processor
block defines how a post-processor is configured.
# builds.pkr.hcl
build {
# ... build image
post-processor "checksum" { # checksum image
checksum_types = [ "md5", "sha512" ] # checksum the artifact
keep_input_artifact = true # keep the artifact
}
post-processor "amazon-import" { # upload image to amazon
}
}
Each post-processor
runs after each defined build. A post-processor takes the
Artifact
from a build. Post-processors are optional, and they can be used to
upload artifacts, re-package, or more. The list of available post-processors
can be found in the post-processors section.
A post-processor
can also take the Artifact
from another post-processor
when it is defined in a post-processors
block list, that is a list of
chained post processors.
Note: The input 'artifact' received by a post-processor will be automatically deleted by default.
»Keep an input artifact
To prevent an input artifact from being deleted, you can set the
keep_input_artifact
field to true to make Packer keep both artifacts. For
example if we want to checksum an artifact and keep the artifact:
# builds.pkr.hcl
build {
# ...
post-processor "checksum" {
checksum_types = [ "md5", "sha512" ]
keep_input_artifact = true
}
}
»Run on Specific Builds
You can use the only
or except
configurations to run a post-processor only
with specific sources. These two configurations do what you expect: only
will
only run the post-processor on the specified sources and except
will run the
post-processor on anything other than the specified sources.
An example of only
being used is shown below, but the usage of except
is
effectively the same:
# builds.pkr.hcl
build {
# ...
post-processor "checksum" {
checksum_types = [ "md5", "sha512" ]
keep_input_artifact = true
only = ["amazon-ebs.example"]
}
}
The values within only
or except
are source names, not builder types.
»Build Contextual Variables
Packer allows to access connection information and basic instance state
information from a post-processor. These information are stored in the build
variable. Check out the Contextual
Variables documentation to learn more
about and see some examples of how to use them.
»Related
- The
post-processors
block allows to define one or more chain ofpost-processor
s that will take the output from the build and provision steps.