Implement the wheel part of PEP 517 (#2)

Cargo.toml

@@ -47,6 +47,8 @@ platforms = "0.2.0"
 shlex = "0.1.1"
 cbindgen = "0.8.7"
 walkdir = "2.2.8"
+flate2 = "1.0.9"
+tar = "0.4.26"
 
 [dev-dependencies]
 indoc = "0.3.3"

Readme.md

@@ -116,6 +116,32 @@ my-project
     └── lib.rs
 ```
 
+## pyproject.toml
+
+pyo3-pack has partial support for building through pyproject.toml. To use it, create a `pyproject.toml` next to your `Cargo.toml` with the following content:
+
+```toml
+[build-system]
+requires = ["pyo3-pack", "toml"]
+build-backend = "pyo3_pack"
+```
+
+You can then e.g. install your package with `pip install .`. With `pip install . -v` you can see the output of cargo and pyo3-pack.
+
+You can use the options `manylinux`, `skip-auditwheel`, `bindings`, `cargo-extra-args` and `rustc-extra-args` under `[tool.pyo3-pack]` the same way you would when running pyo3-pack directly. The `bindings` key is required for cffi and bin projects as those can't be automatically detected.
+
+```toml
+[build-system]
+requires = ["pyo3-pack", "toml"]
+build-backend = "pyo3_pack"
+
+[tool.pyo3-pack]
+bindings = "cffi"
+cargo-extra-args="-v"
+```
+
+Currently, only the wheel build part of [PEP 517](https://snarky.ca/clarifying-pep-518/) is supported. Building source distribution doesn't work yet, which means isolated builds will fail.
+
 ## Manylinux and auditwheel
 
 For portability reasons, native python modules on linux must only dynamically link a set of very few libraries which are installed basically everywhere, hence the name manylinux. The pypa offers a special docker container and a tool called [auditwheel](https://github.com/pypa/auditwheel/) to ensure compliance with the [manylinux rules](https://www.python.org/dev/peps/pep-0513/#the-manylinux1-policy).
@@ -132,7 +158,7 @@ pyo3-pack itself is manylinux compliant when compiled for the musl target. The b
 
 ## PyPy
 
-pyo3-pack can build wheels for pypy with pyo3. Note that pypy support in pyo3 is unreleased as of this writing. Also note that pypy [is not compatible with manylinux1](https://github.com/antocuni/pypy-wheels#why-not-manylinux1-wheels) and you can't publish pypy wheel to pypi pypy has been only tested manually and on linux. See [#115](https://github.com/PyO3/pyo3-pack/issues/115) for more details.
+pyo3-pack can build wheels for pypy with pyo3. Note that pypy [is not compatible with manylinux1](https://github.com/antocuni/pypy-wheels#why-not-manylinux1-wheels) and you can't publish pypy wheel to pypi pypy has been only tested manually and on linux. See [#115](https://github.com/PyO3/pyo3-pack/issues/115) for more details.
 
 ### Build
 

pyo3_pack/__init__.py

@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+"""
+pyo3-pack's implementation of the PEP 517 interface. Calls pyo3-pack through subprocess
+
+Currently pyo3-pack doesn't have json output (nor is there a way to the user visible output off),
+so this parse the user facing messages.
+
+TODO: Don't require the user to specify toml as a requirement in the pyproject.toml
+"""
+
+import os
+import shutil
+import subprocess
+from typing import List, Dict
+
+import toml
+
+available_options = [
+    "manylinux",
+    "skip-auditwheel",
+    "bindings",
+    "cargo-extra-args",
+    "rustc-extra-args",
+]
+
+
+def get_config() -> Dict[str, str]:
+    with open("pyproject.toml") as fp:
+        pyproject_toml = toml.load(fp)
+    return pyproject_toml.get("tool", {}).get("pyo3-pack", {})
+
+
+def get_config_options() -> List[str]:
+    config = get_config()
+    options = []
+    for key, value in config.items():
+        if key not in available_options:
+            raise RuntimeError(
+                "{} is not a valid option for pyo3-pack. Valid are: {}".format(
+                    key, ", ".join(available_options)
+                )
+            )
+        options.append("--{}={}".format(key, value))
+    return options
+
+
+# noinspection PyUnusedLocal
+def build_wheel(wheel_directory, config_settings=None, metadata_directory=None):
+    command = ["pyo3-pack", "build", "-i", "python"]
+    command.extend(get_config_options())
+
+    print("Running `{}`".format(" ".join(command)))
+    output = subprocess.check_output(command, universal_newlines=True)
+    print(output)
+    # Get the filename from `📦 Built wheel [for CPython 3.6m] to /home/user/project`
+    filename = os.path.split(output.strip().splitlines()[-1].split(" to ")[1])[1]
+    shutil.copy2("target/wheels/" + filename, os.path.join(wheel_directory, filename))
+    return filename
+
+
+# noinspection PyUnusedLocal
+def build_sdist(sdist_directory, config_settings=None):
+    command = [
+        "pyo3-pack",
+        "pep517",
+        "write-sdist",
+        "--sdist-directory",
+        sdist_directory,
+    ]
+    command.extend(get_config_options())
+
+    print("Running `{}`".format(" ".join(command)))
+    output = subprocess.check_output(command, universal_newlines=True)
+    print(output)
+    return output.strip().splitlines()[-1]
+
+
+# noinspection PyUnusedLocal
+def get_requires_for_build_wheel(config_settings=None):
+    if get_config().get("bindings") == "cffi":
+        return ["cffi"]
+    else:
+        return []
+
+
+# noinspection PyUnusedLocal
+def get_requires_for_build_sdist(config_settings=None):
+    return []
+
+
+# noinspection PyUnusedLocal
+def prepare_metadata_for_build_wheel(metadata_directory, config_settings=None):
+    command = [
+        "pyo3-pack",
+        "pep517",
+        "write-dist-info",
+        "--metadata-directory",
+        metadata_directory,
+    ]
+    command.extend(get_config_options())
+
+    print("Running `{}`".format(" ".join(command)))
+    output = subprocess.check_output(command, universal_newlines=True)
+    print(output)
+    return output.strip().splitlines()[-1]

src/build_context.rs

@@ -2,6 +2,7 @@
 use crate::auditwheel::auditwheel_rs;
 use crate::compile;
 use crate::compile::warn_missing_py_init;
+use crate::module_writer::write_python_part;
 use crate::module_writer::WheelWriter;
 use crate::module_writer::{write_bin, write_bindings_module, write_cffi_module};
 use crate::Manylinux;
@@ -215,20 +216,11 @@ impl BuildContext {
         Ok(artifact)
     }
 
-    fn get_unversal_tags(&self) -> (String, Vec<String>) {
-        let tag = format!(
-            "py2.py3-none-{platform}",
-            platform = self.target.get_platform_tag(&self.manylinux)
-        );
-        let tags = self.target.get_py2_and_py3_tags(&self.manylinux);
-        (tag, tags)
-    }
-
     /// Builds a wheel with cffi bindings
     pub fn build_cffi_wheel(&self) -> Result<PathBuf, Error> {
         let artifact = self.compile_cdylib(None, None)?;
 
-        let (tag, tags) = self.get_unversal_tags();
+        let (tag, tags) = self.target.get_universal_tags(&self.manylinux);
 
         let mut builder =
             WheelWriter::new(&tag, &self.out, &self.metadata21, &self.scripts, &tags)?;
@@ -266,7 +258,7 @@ impl BuildContext {
         auditwheel_rs(&artifact, &self.target, &self.manylinux)
             .context("Failed to ensure manylinux compliance")?;
 
-        let (tag, tags) = self.get_unversal_tags();
+        let (tag, tags) = self.target.get_universal_tags(&self.manylinux);
 
         if !self.scripts.is_empty() {
             bail!("Defining entrypoints and working with a binary doesn't mix well");
@@ -275,6 +267,14 @@ impl BuildContext {
         let mut builder =
             WheelWriter::new(&tag, &self.out, &self.metadata21, &self.scripts, &tags)?;
 
+        match self.project_layout {
+            ProjectLayout::Mixed(ref python_module) => {
+                write_python_part(&mut builder, python_module, &self.module_name)
+                    .context("Failed to add the python module to the package")?;
+            }
+            ProjectLayout::PureRust => {}
+        }
+
         // I wouldn't know of any case where this would be the wrong (and neither do
         // I know a better alternative)
         let bin_name = artifact