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Version: 2.18 (deprecated)


A self-contained Python function suitable for uploading to AWS Lambda.


Backend: pants.backend.awslambda.python



Entry point to the AWS Lambda handler.

You can specify a full module like '' or use a shorthand to specify a file name, using the same syntax as the sources field, e.g. ''.

This is re-exported at lambda_function.handler in the resulting package to be used as the configured handler of the Lambda in AWS. It can also be accessed under its source-root-relative module path, for example:


Iterable[str] | None
default: None

The platforms the built PEX should be compatible with.

There must be built wheels available for all of the foreign platforms, rather than sdists.

You can give a list of multiple complete platforms to create a multiplatform PEX, meaning that the PEX will be executable in all of the supported environments.

Complete platforms should be addresses of file targets that point to files that contain complete platform JSON as described by Pex (

N.B.: only one of this and runtime can be set. If runtime is set, a default complete platform is chosen, if one is known for that runtime. Explicitly set this to [] to use the platform's ambient interpreter, such as when running in an docker environment.


Iterable[str] | None
default: None

Addresses to other targets that this target depends on, e.g. ['helloworld/subdir:lib', 'helloworld/', '3rdparty:reqs#django'].

This augments any dependencies inferred by Pants, such as by analyzing your imports. Use pants dependencies or pants peek on this target to get the final result.

See for more about how addresses are formed, including for generated targets. You can also run pants list :: to find all addresses in your project, or pants list dir to find all addresses defined in that directory.

If the target is in the same BUILD file, you can leave off the BUILD file path, e.g. :tgt instead of helloworld/subdir:tgt. For generated first-party addresses, use ./ for the file path, e.g. ./; for all other generated targets, use :tgt#generated_name.

You may exclude dependencies by prefixing with !, e.g. ['!helloworld/subdir:lib', '!./sibling.txt']. Ignores are intended for false positives with dependency inference; otherwise, simply leave off the dependency from the BUILD file.


str | None
default: None

A human-readable description of the target.

Use pants list --documented :: to see all targets with descriptions.


str | None
default: '__local__'

Specify which environment target to consume environment-sensitive options from.

Once environments are defined in [environments-preview].names, you can specify the environment for this target by its name. Any fields that are defined in that environment will override the values from options set by pants.toml, command line values, or environment variables.

You can specify multiple valid environments by using parametrize. If __local__ is specified, Pants will fall back to the local_environment defined for the current platform, or no environment if no such environment exists.


default: True

Whether to resolve requirements and include them in the AWS Lambda artifact. This is most useful with Lambda Layers to make code uploads smaller when third-party requirements are in layers.


str | None
default: None

Where the built asset should be located.

If undefined, this will use the path to the BUILD file, followed by the target name. For example, src/python/project:app would be src.python.project/app.ext.

When running pants package, this path will be prefixed by --distdir (e.g. dist/).

Warning: setting this value risks naming collisions with other package targets you may have.


Iterable[str] | None
default: ()

Any extra arguments to pass to the pex3 venv create invocation that is used to create the final zip file.

For example, pex3_venv_create_extra_args=["--collisions-ok"], if using packages that have colliding files that aren't required at runtime (errors like "Encountered collisions populating ...").


str | None
default: None

The resolve from [python].resolves to use.

If not defined, will default to [python].default_resolve.

All dependencies must share the same value for their resolve field.


str | None
default: None

The identifier of the AWS Lambda runtime to target (pythonX.Y). See

N.B.: only one of this and complete_platforms can be set. If runtime is set, a default complete platform is chosen, if one is known for that runtime. If you have issues either packaging the AWS Lambda PEX or running it as a deployed AWS Lambda function, you should try using an explicit complete_platforms instead.


Iterable[str] | None
default: None

Arbitrary strings to describe a target.

For example, you may tag some test targets with 'integration_test' so that you could run pants --tag='integration_test' test :: to only run on targets with that tag.