packer.py

About

packer.py - python library for interacting with hashicorp packer CLI executable.

Project follows semantic versioning , v0.x.x API should be considered unstable, API will change frequently, please plan accordingly.

Installation

packer.py can be installed via pip:

$ pip install packer.py

Configuration

Packer Executable

Specify Packer Location

Access to hashicorp packer executable is needed in order to use packer.py. When generating commands, if no location is specified, the following defaults are used.

*nix:	/usr/local/packer
macOS:	/usr/local/packer
windows:	packer.exe

These defaults can be overridden by explicitly setting the location of packer for your environment.

PackerExecutable(executable_path="/usr/local/bin/packer")

or

PackerExecutable("/usr/local/bin/packer")

Machine Readable Output

Commands are executed with packer's machine readable format enabled by default. This can be disabled by setting

PackerExecutable(machine_readable=False)

Running Commands

The following commands are currently supported:

• build
• inspect
• validate
• version

Below is the packer.py equivalent of running these packer CLI commands

Configuration

Templates

Templates are specified by passing their filepath to the command.

template = 'tests/templates/test_template1.json'
PackerExecutable().validate(template)

Templates can also be specified as a string literal.

template = """
{
    "variables": {
        "my_var1": "{{env `key1`}}"
    },
    "builders": [
        {
            "type": "file",
            "content": "Lorem ipsum dolor sit amet {{user `my_var1`}} ",
            "target": "/tmp/packer.test"
        }
    ]
}
"""
PackerExecutable().validate(template)

packerlicious templates can also be used and combined with packer.py.

from packerlicious import builder, Template, EnvVar
from packerpy import PackerExecutable
var1 = EnvVar("my_var1")
var2 = EnvVar("my_var2")
file_builder = builder.File()
file_builder = builder.File(content="{} more words {}".format(var2.ref().data, var1.ref().data),
                            target="/tmp/packer.test"
                            )
template = Template()
template.add_variable([var1, var2])
template.add_builder(file_builder)
p = PackerExecutable("/usr/local/bin/packer")
template_vars = {'my_var1': 'my_val1', 'my_var2': 'my_val2'}
p.build(template.to_json(),
        var=template_vars
        )

Command Arguments

packer CLI commands arguments can be specified by passing them as packer.py method arguments.

$ packer validate -syntax-only -var "key1=my_value" tests/templates/test_template1.json

p = PackerExecutable("/usr/local/bin/packer")
template = 'tests/templates/test_template1.json'
p.validate(template,
           syntax_only=True,
           var="key1=my_value"
           )

The following rules are used by packer.py when converting to packer CLI commands.

Dashes in Packer Command Option Names

If the packer command option has a dash in it, pass it to packer.py with an underscore.

-on-error=cleanup:	on_error='cleanup'

Boolean Values and Implicit Value Command Options

If the packer command option is either a boolean option or an option with an implicit value, pass it to packer.py as a boolean.

-color=false:	color=False
-force:	force=True

Repeating Command Options

If the packer command options can be specified multiple times, pass the value as a dictionary to packer.py. Multiple -var option is an example of this.

$ packer build -var 'my_var1=my_val1' -var 'my_var2=my_val2' tests/templates/test_template1.json

from packerpy import PackerExecutable
p = PackerExecutable("/usr/local/bin/packer")
template = 'tests/templates/test_template1.json'
template_vars = { 'my_var1': 'my_val1', 'my_var2': 'my_val2' }
p.build(template,
           var=template_vars
           )

Build

$ packer build template.json

>>> from packerpy import PackerExecutable
>>> p = PackerExecutable("/usr/local/bin/packer")
>>> (ret, out, err) = p.build('tests/templates/test_template1.json')
>>> ret==0
True
>>> print(ret)
0
>>> print(out)
b"1552841678,,ui,say,Build 'file' finished.\n1552841678,,ui,say,\\n==> Builds finished. The artifacts of successful builds are:\n1552841678,file,artifact-count,1\n1552841678,file,artifact,0,builder-id,packer.file\n1552841678,file,artifact,0,id,File\n1552841678,file,artifact,0,string,Stored file: /tmp/packer.test \n1552841678,file,artifact,0,files-count,1\n1552841678,file,artifact,0,file,0,/tmp/packer.test \n1552841678,file,artifact,0,end\n1552841678,,ui,say,--> file: Stored file: /tmp/packer.test \n"
>>> print(err)
b''

Example of a failed build.

>>> from packerpy import PackerExecutable
>>> p = PackerExecutable("/usr/local/bin/packer")
>>> bad_template = """{
...     "builders": [
...         {
...             "type": "amazon-ebs",
...             "access_key": "..."
...         }
...     ]
... }
... """
>>> (ret, out, err) = p.build(bad_template)
>>> ret==0
False
>>> print(ret)
1
>>> print(out)
b'1552841800,,ui,error,5 error(s) occurred:\\n\\n* ami_name must be specified\\n* ami_name must be between 3 and 128 characters long\\n* An ssh_username must be specified\\n  Note: some builders used to default ssh_username to "root".\\n* A source_ami or source_ami_filter must be specified\\n* An instance_type must be specified\n'
>>> print(err)
b''

Inspect

$ packer inspect template.json

>>> from packerpy import PackerExecutable
>>> p = PackerExecutable("/usr/local/bin/packer")
>>> (ret, out, err) = p.inspect('tests/templates/test_template1.json')
>>> ret==0
True
>>> print(ret)
0
>>> print(out)
b"1552841499,,ui,say,Optional variables and their defaults:\\n\n1552841499,,template-variable,my_var1,{{env `key1`}},0\n1552841499,,ui,say,  my_var1 = {{env `key1`}}\n1552841499,,ui,say,\n1552841499,,ui,say,Builders:\\n\n1552841499,,template-builder,file,file\n1552841499,,ui,say,  file\n1552841499,,ui,say,\n1552841499,,ui,say,Provisioners:\\n\n1552841499,,ui,say,  <No provisioners>\n1552841499,,ui,say,\\nNote: If your build names contain user variables or template\\nfunctions such as 'timestamp'%!(PACKER_COMMA) these are processed at build time%!(PACKER_COMMA)\\nand therefore only show in their raw form here.\n"
>>> print(err)
b''

Validate

$ packer validate template.json

>>> from packerpy import PackerExecutable
>>> p = PackerExecutable("/usr/local/bin/packer")
>>> (ret, out, err) = p.validate('tests/templates/test_template1.json')
>>> ret==0
True
>>> print(ret)
0
>>> print(out)
b'1552840497,,ui,say,Template validated successfully.\n'
>>> print(err)
b''

Example of a template which failed to validation.

>>> from packerpy import PackerExecutable
>>> p = PackerExecutable("/usr/local/bin/packer")
>>> bad_template = """{
...     "builders": [
...         {
...             "type": "amazon-ebs",
...             "access_key": "..."
...         }
...     ]
... }
... """
>>> (ret, out, err) = p.validate(bad_template)
>>> ret==0
False
>>> print(ret)
1
>>> print(out)
b'1552840892,,ui,error,Template validation failed. Errors are shown below.\\n\n1552840892,,ui,error,Errors validating build \'amazon-ebs\'. 5 error(s) occurred:\\n\\n* ami_name must be specified\\n* ami_name must be between 3 and 128 characters long\\n* An ssh_username must be specified\\n  Note: some builders used to default ssh_username to "root".\\n* A source_ami or source_ami_filter must be specified\\n* An instance_type must be specified\n'
>>> print(err)
b''

Version

$ packer version

>>> from packerpy import PackerExecutable
>>> p = PackerExecutable("/usr/local/bin/packer")
>>> (ret, out, err) = p.version()
>>> ret==0
True
>>> print(ret)
0
>>> print(out)
b'1552840138,,version,1.0.3\n1552840138,,version-prelease,\n1552840138,,version-commit,c0ddb4a+CHANGES\n1552840138,,ui,say,Packer v1.0.3\n1552840138,,ui,say,\\nYour version of Packer is out of date! The latest version\\nis 1.3.5. You can update by downloading from www.packer.io\n'
>>> print(err)
b''

Licensing

packer.py is licensed under the Apache license 2.0. See LICENSE for the full license text.