Remove Protobuf and AWS Lambda from example (#84)

We got feedback in Slack that these two backends were making the example too complex. 

> I could not use that repo as a template because of the aws and protobuf stuff. ie do you want the repo to be a reusable template? or a fully baked example?

We would rather have the example repo be very easy to get started than to show every bell and whistle of Pants. Our docs are for the niche features like AWS Lambdas. Our example repo is to allow you to very easily try out Pants to get a feel for it before committing to prototyping in your own repo.

Author: Eric-Arellano

BUILD

@@ -1,24 +1,7 @@
 # Copyright 2020 Pants project contributors.
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-
-# A macro that turns every entry in this directory's requirements.txt into a target
-# with the name of the corresponding dist.
-#
-# For example, `translate>=3.2.1` expands to:
-#
-#   python_requirement_library(
-#     name='translate',
-#     requirements=['translate>=3.2.1']
-#   )
-#
-# We set `module_mapping` for any requirements whose module names differ from the project's name so that dependency
-# inference works.
-#
-# Refer to https://www.pantsbuild.org/docs/python-third-party-dependencies.
-python_requirements(
-  module_mapping={
-    "ansicolors": ["colors"],
-    "setuptools": ["pkg_resources"],
-  },
-)
+# A macro that turns every entry in this directory's requirements.txt into a
+# `python_requirement_library` target. Refer to
+# https://www.pantsbuild.org/docs/python-third-party-dependencies.
+python_requirements()

README.md

@@ -171,14 +171,6 @@ This will build both a `.whl` bdist and a `.tar.gz` sdist.
 We can also remove the `setup_py_commands` field from `helloworld/util/BUILD` to have Pants instead generate a 
 `setup.py` file, with all the relevant code in a chroot.
 
-## Build an AWS Lambda
-
-(This example only works on Linux because it has an sdist. See https://www.pantsbuild.org/docs/awslambda-python.)
-
-```
-./pants package helloworld/awslambda.py
-```
-
 ## Count lines of code
 
 ```

constraints.txt

@@ -8,13 +8,11 @@ importlib-metadata==4.6.3
 libretranslatepy==2.1.1
 lxml==4.6.3
 pip==21.2.2
-protobuf==3.17.3
 requests==2.26.0
 setuptools==56.2.0
 six==1.16.0
 translate==3.6.1
 types-futures==0.1.6
-types-protobuf==3.17.4
 types-setuptools==57.0.0
 typing-extensions==3.10.0.0
 urllib3==1.26.6

helloworld/BUILD

@@ -24,13 +24,3 @@ pex_binary(
     name="pex_binary",
     entry_point="main.py",
 )
-
-# This target allows us to create an AWS Lambda binary via `./pants package`.
-#  See https://www.pantsbuild.org/docs/awslambda-python.
-#
-# Note: This has sdist dependencies, so it must be built on Linux.
-python_awslambda(
-    name="awslambda",
-    handler="awslambda.py:handler",
-    runtime="python3.7",
-)

helloworld/awslambda.py

@@ -3,15 +3,13 @@
 
 from colors import green
 
-from helloworld.config import load_config
 from helloworld.greet.greeting import Greeter
+from helloworld.util.config import Config
 
 
 def say_hello() -> None:
-    config = load_config()
-    greeter = Greeter(
-        languages=list(config.languages), greetings=list(config.greetings)
-    )
+    config = Config.load_from_json_resource(__name__, "config.json")
+    greeter = Greeter(languages=config.languages, greetings=config.greetings)
     sentence = greeter.greet("world")
     print(green(sentence))
 

helloworld/config.py

@@ -0,0 +1,21 @@
+# Copyright 2020 Pants project contributors.
+# Licensed under the Apache License, Version 2.0 (see LICENSE).
+
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+
+import pkg_resources
+
+
+@dataclass
+class Config:
+    languages: list[str]
+    greetings: list[str]
+
+    @classmethod
+    def load_from_json_resource(cls, pkg_name: str, resource_name: str) -> Config:
+        resource_content = pkg_resources.resource_string(pkg_name, resource_name)
+        parsed = json.loads(resource_content)
+        return cls(languages=parsed["languages"], greetings=parsed["greetings"])

helloworld/main.py

@@ -1,10 +1,10 @@
 # Copyright 2020 Pants project contributors.
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-from helloworld.util.config_loader import load_config_from_json
+from helloworld.util.config import Config
 
 
 def test_load_config_from_json() -> None:
-    config = load_config_from_json(__name__, "config_loader_test_data.json")
+    config = Config.load_from_json_resource(__name__, "config_test_data.json")
     assert config.languages == ["af", "zh"]
     assert config.greetings == ["hi", "hey"]