pythonruntime

README

Paketo Python Runtime Cloud Native Buildpack

The Python Runtime CNB provides the Python 3 runtime. The buildpack installs Python onto the $PATH which makes it available for subsequent buildpacks and in the final running container. It also sets the $PYTHONPATH environment variable.

Integration

The Python Runtime CNB provides python as a dependency. Downstream buildpacks, can require the python dependency by generating Build Plan TOML file that looks like the following:

[[requires]]
  # The name of the Python dependency is "python". This value is considered
  # part of the public API for the buildpack and will not change without a plan
  # for deprecation.
  name = "python"
  # The version of the Python dependency is not required. In the case it
  # is not specified, the buildpack will provide the default version, which can
  # be seen in the buildpack.toml file.
  # If you wish to request a specific version, the buildpack supports
  # specifying a semver constraint in the form of "3.*", "3.8.*", or even
  # "3.8.2".
  version = "3.8.2"
  # The Python buildpack supports some non-required metadata options.
  [requires.metadata]

    # Setting the build flag to true will ensure that the Python
    # depdendency is available on the $PATH for subsequent buildpacks during
    # their build phase. If you are writing a buildpack that needs to use Python
    # during its build process, this flag should be set to true.
    build = true

    # Setting the launch flag to true will ensure that the python runtime is
    # available to the running application. If you are writing an application that needs to run
    # python at runtime, this flag should be set to true.
    launch = true

To package this buildpack for consumption:

$ ./scripts/package.sh

This builds the buildpack's Go source using GOOS=linux by default. You can supply another value as the first argument to package.sh.

buildpack.yml Configurations

In order to specify a particular version of python you can provide an optional buildpack.yml in the root of the application directory.

python:
  # this allows you to specify a version constraint for the python depdendency
  # any valid semver constaints (e.g. 3.*) are also acceptable
  version: ~3

Documentation

Index

• Constants
• func Build(entries EntryResolver, dependencies DependencyManager, ...) packit.BuildFunc
• func Detect(buildpackYMLParser VersionParser) packit.DetectFunc
• type BuildPlanMetadata
• type BuildPlanRefinery
  • func NewBuildPlanRefinery() BuildPlanRefinery
  • func (r BuildPlanRefinery) BillOfMaterials(dependency postal.Dependency) packit.BuildpackPlanEntry
• type BuildpackYMLParser
  • func NewBuildpackYMLParser() BuildpackYMLParser
  • func (p BuildpackYMLParser) ParseVersion(path string) (string, error)
• type DependencyManager
• type EntryResolver
• type LogEmitter
  • func NewLogEmitter(output io.Writer) LogEmitter
  • func (l LogEmitter) Candidates(entries []packit.BuildpackPlanEntry)
  • func (l LogEmitter) Environment(env packit.Environment)
  • func (l LogEmitter) Title(info packit.BuildpackInfo)
• type PlanEntryResolver
  • func NewPlanEntryResolver(logger LogEmitter) PlanEntryResolver
  • func (r PlanEntryResolver) Resolve(entries []packit.BuildpackPlanEntry) packit.BuildpackPlanEntry
• type PlanRefinery
• type VersionParser

Constants

const (
	Python = "python"

	DepKey = "dependency-sha"
)

Functions

func Build

func Build(entries EntryResolver, dependencies DependencyManager, planRefinery PlanRefinery, logs LogEmitter, clock chronos.Clock) packit.BuildFunc

func Detect

func Detect(buildpackYMLParser VersionParser) packit.DetectFunc

Types

type BuildPlanMetadata

type BuildPlanMetadata struct {
	Version       string `toml:"version"`
	VersionSource string `toml:"version-source"`
}

type BuildPlanRefinery

type BuildPlanRefinery struct{}

func NewBuildPlanRefinery

func NewBuildPlanRefinery() BuildPlanRefinery

func (BuildPlanRefinery) BillOfMaterials

func (r BuildPlanRefinery) BillOfMaterials(dependency postal.Dependency) packit.BuildpackPlanEntry

type BuildpackYMLParser

type BuildpackYMLParser struct{}

func NewBuildpackYMLParser

func NewBuildpackYMLParser() BuildpackYMLParser

func (BuildpackYMLParser) ParseVersion

func (p BuildpackYMLParser) ParseVersion(path string) (string, error)

type DependencyManager

type DependencyManager interface {
	Resolve(path, id, version, stack string) (postal.Dependency, error)
	Install(dependency postal.Dependency, cnbPath, layerPath string) error
}

type EntryResolver

type EntryResolver interface {
	Resolve([]packit.BuildpackPlanEntry) packit.BuildpackPlanEntry
}

type LogEmitter

type LogEmitter struct {
	scribe.Emitter
}

func NewLogEmitter

func NewLogEmitter(output io.Writer) LogEmitter

func (LogEmitter) Candidates

func (l LogEmitter) Candidates(entries []packit.BuildpackPlanEntry)

func (LogEmitter) Environment

func (l LogEmitter) Environment(env packit.Environment)

func (LogEmitter) Title

func (l LogEmitter) Title(info packit.BuildpackInfo)

type PlanEntryResolver

type PlanEntryResolver struct {
	// contains filtered or unexported fields
}

func NewPlanEntryResolver

func NewPlanEntryResolver(logger LogEmitter) PlanEntryResolver

func (PlanEntryResolver) Resolve

func (r PlanEntryResolver) Resolve(entries []packit.BuildpackPlanEntry) packit.BuildpackPlanEntry

type PlanRefinery

type PlanRefinery interface {
	BillOfMaterials(dependency postal.Dependency) packit.BuildpackPlanEntry
}

type VersionParser

type VersionParser interface {
	ParseVersion(path string) (version string, err error)
}