feat: allow skipping py2 installation

allow skipping py2 installation

examples/verify_versions/BUILD.bazel → examples/py3_only/BUILD

@@ -6,13 +6,6 @@ py_binary(
     python_version = "PY3",
 )
 
-py_binary(
-    name = "main_py2",
-    srcs = ["main.py"],
-    main = "main.py",
-    python_version = "PY2",
-)
-
 filegroup(
     name = "srcs",
     srcs = [

examples/py3_only/WORKSPACE

@@ -0,0 +1,12 @@
+workspace(name = "examples_p3_only")
+
+local_repository(
+    name = "dpu_rules_pyenv",
+    path = "../../",
+)
+
+load("@dpu_rules_pyenv//pyenv:defs.bzl", "pyenv_install")
+
+pyenv_install(
+    py3 = "3.7.7",
+)

examples/py3_only/main.py

@@ -0,0 +1,2 @@
+import sys
+print(sys.version)

pyenv/defs.bzl

@@ -24,11 +24,13 @@ CONFIGURATIONS = {
     }
 }
 
-BUILD_FILE_CONTENT = """# This file was automatically generated by @dpu_rules_pyenv//pyenv:defs.bzl
+BUILD_FILE_CONTENT_HEADER = """# This file was automatically generated by @dpu_rules_pyenv//pyenv:defs.bzl
 package(default_visibility = ["//visibility:public"])
 
 load("@bazel_tools//tools/python:toolchain.bzl", "py_runtime_pair")
+"""
 
+BUILD_CONTENT_PY2_PY3 = """
 # export interpreter so it can accessed as a regular file
 exports_files([
     "{py2_dir_link}/{interpreter}",
@@ -62,6 +64,49 @@ toolchain(
 )
 """
 
+BUILD_CONTENT_PY3_ONLY = """
+# export interpreter so it can accessed as a regular file
+exports_files([
+    "{py3_dir_link}/{interpreter}"
+])
+
+py_runtime(
+    name = "python_{py3}_runtime",
+    files = glob(["versions/{py3}/**/*"], exclude_directories = 0),
+    interpreter = "versions/{py3}/{interpreter_path}",
+    python_version = "PY3"
+)
+
+py_runtime_pair(
+    name = "runtimes",
+    py3_runtime = "@pyenv//:python_{py3}_runtime",
+)
+
+toolchain(
+    name = "python_toolchain",
+    toolchain = ":runtimes",
+    toolchain_type = "@bazel_tools//tools/python:toolchain_type",
+)
+"""
+
+def _generate_build_file_content(py2, 
+                                 py3, 
+                                 py2_dir_link, 
+                                 py3_dir_link,
+                                 interpreter_path,
+                                 interpreter = INTERPRETER_DEFAULT_NAME):
+    build_file_content_template = BUILD_FILE_CONTENT_HEADER
+    if py2:
+        build_file_content_template += BUILD_CONTENT_PY2_PY3
+    else:
+        build_file_content_template += BUILD_CONTENT_PY3_ONLY
+    return build_file_content_template.format(py2 = py2, 
+            py3 = py3, 
+            py2_dir_link = py2_dir_link, 
+            py3_dir_link = py3_dir_link,
+            interpreter = interpreter,
+            interpreter_path = interpreter_path)
+
 def _is_windows(repository_ctx):
     """Returns true when os is recognized as windows
     Args:
@@ -147,14 +192,15 @@ def _setup_links(repository_ctx, version, dir_name):
 def _setup_build_files(repository_ctx, py2, py3, py2_dir, py3_dir):
     interpreter_dir = _get_config(repository_ctx)["interpreter_dir"]
     interpreter_path = "{}/{}".format(interpreter_dir, INTERPRETER_DEFAULT_NAME) if interpreter_dir else INTERPRETER_DEFAULT_NAME
+    build_file_content = _generate_build_file_content(py2 = py2, 
+                                               py3 = py3, 
+                                               py2_dir_link = py2_dir, 
+                                               py3_dir_link = py3_dir,
+                                               interpreter = INTERPRETER_DEFAULT_NAME,
+                                               interpreter_path = interpreter_path)
     repository_ctx.file(
         "BUILD",
-        content = BUILD_FILE_CONTENT.format(py2 = py2, 
-                                            py3 = py3, 
-                                            py2_dir_link = py2_dir, 
-                                            py3_dir_link = py3_dir,
-                                            interpreter = INTERPRETER_DEFAULT_NAME,
-                                            interpreter_path = interpreter_path)
+        content = build_file_content
     )
 
 def _pyenv_install_impl(repository_ctx):
@@ -164,18 +210,19 @@ def _pyenv_install_impl(repository_ctx):
     py3_dir = repository_ctx.attr.py3_dir
 
     _setup_pyenv(repository_ctx)
-    _install_python(repository_ctx, py2)
+    if py2:
+        _install_python(repository_ctx, py2)
+        _setup_links(repository_ctx, py2, py2_dir)
     _install_python(repository_ctx, py3)
-    _setup_links(repository_ctx, py2, py2_dir)
     _setup_links(repository_ctx, py3, py3_dir)
     _setup_build_files(repository_ctx, py2, py3, py2_dir, py3_dir)
 
 _pyenv_install = repository_rule(
     _pyenv_install_impl,
     attrs = {
-        "py2": attr.string(mandatory = True, doc = "exact version of python2"),
+        "py2": attr.string(mandatory = False, doc = "exact version of python2"),
         "py3": attr.string(mandatory = True, doc = "exact version of python3"),
-        "py2_dir": attr.string(mandatory = True, doc = "directory for python2"),
+        "py2_dir": attr.string(mandatory = False, doc = "directory for python2"),
         "py3_dir": attr.string(mandatory = True, doc = "directory for python3"),
         "hermetic": attr.bool(default = True, doc = "True if pyenv should be downloaded, False if local pyenv should be used"),
         "pyenv_repo": attr.string_dict(default = {
@@ -191,7 +238,7 @@ _pyenv_install = repository_rule(
     }
 )
 
-def pyenv_install(py2, py3, py2_dir = PY2_DEFAULT_DIR_NAME, py3_dir = PY3_DEFAULT_DIR_NAME, name = DEFAULT_REPOSITORY_NAME, **kwargs):
+def pyenv_install(py3, py2 = None, py3_dir = PY3_DEFAULT_DIR_NAME, py2_dir = PY2_DEFAULT_DIR_NAME, name = DEFAULT_REPOSITORY_NAME, **kwargs):
     """
     Macro to install and register a py_runtime_pair.
     """