feat: add formatted indentifier printout

action.yml

@@ -13,6 +13,10 @@ inputs:
     description: 'File containing the config, defaults to {package}/pyproject.toml'
     required: false
     default: ''
+  print-build-identifiers:
+    description: 'Print build identifiers and exit. Set id: to access these in a later step'
+    required: false
+    default: ''
 branding:
   icon: package
   color: yellow
@@ -36,5 +40,6 @@ runs:
         ${{ inputs.package-dir }}
         --output-dir ${{ inputs.output-dir }}
         --config-file "${{ inputs.config-file }}"
+        --print-build-identifiers "${{ inputs.print-build-identifiers }}"
         2>&1
       shell: bash

cibuildwheel/__main__.py

@@ -100,8 +100,16 @@ def main() -> None:
 
     parser.add_argument(
         "--print-build-identifiers",
-        action="store_true",
-        help="Print the build identifiers matched by the current invocation and exit.",
+        action="store",
+        const="{identifier}",
+        nargs="?",
+        help="""
+            Print the build identifiers matched by the current invocation and
+            exit.  Optionally, specify a format string to print the identifiers.
+            Available replacements are {identifier}, {arch}, {version}, {os}
+            (manylinux / musllinux / macos / windows), and {impl} (CPython,
+            PyPy). Default: {identifier}.
+        """,
     )
 
     parser.add_argument(
@@ -210,7 +218,27 @@ def build_in_directory(args: CommandLineArguments) -> None:
 
     if args.print_build_identifiers:
         for identifier in identifiers:
-            print(identifier)
+            py_ver, os_plat = identifier.split("-")
+            impl = py_ver[:2]
+            version = f"{py_ver[2]}.{py_ver[3:]}"
+
+            if os_plat == "win32":
+                os_ = "win32"
+                arch = "x86"
+            else:
+                os_, arch = os_plat.split("_", maxsplit=1)
+                if os_ == "win32":
+                    arch = arch.upper()
+
+            print(
+                args.print_build_identifiers.format(
+                    identifier=identifier,
+                    arch=arch,
+                    version=version,
+                    os=os_,
+                    impl="CPython" if impl == "cp" else "PyPy",
+                )
+            )
         sys.exit(0)
 
     # Add CIBUILDWHEEL environment variable

cibuildwheel/options.py

@@ -47,7 +47,7 @@ class CommandLineArguments:
     output_dir: Path
     config_file: str
     package_dir: Path
-    print_build_identifiers: bool
+    print_build_identifiers: str | None
     allow_empty: bool
     prerelease_pythons: bool
 

unit_test/utils.py

@@ -14,7 +14,7 @@ def get_default_command_line_arguments() -> CommandLineArguments:
         output_dir=Path("wheelhouse"),
         package_dir=Path("."),
         prerelease_pythons=False,
-        print_build_identifiers=False,
+        print_build_identifiers=None,
     )
 
     return defaults