1# Adapted with modifications from tensorflow/third_party/py/
2"""Repository rule for Python autoconfiguration.
3
4`python_configure` depends on the following environment variables:
5
6  * `PYTHON_BIN_PATH`: location of python binary.
7  * `PYTHON_LIB_PATH`: Location of python libraries.
8"""
9
10_BAZEL_SH = "BAZEL_SH"
11_PYTHON_BIN_PATH = "PYTHON_BIN_PATH"
12_PYTHON_LIB_PATH = "PYTHON_LIB_PATH"
13_PYTHON_CONFIG_REPO = "PYTHON_CONFIG_REPO"
14
15
16def _tpl(repository_ctx, tpl, substitutions={}, out=None):
17    if not out:
18        out = tpl
19    repository_ctx.template(out, Label("//third_party/py:%s.tpl" % tpl),
20                            substitutions)
21
22
23def _fail(msg):
24    """Output failure message when auto configuration fails."""
25    red = "\033[0;31m"
26    no_color = "\033[0m"
27    fail("%sPython Configuration Error:%s %s\n" % (red, no_color, msg))
28
29
30def _is_windows(repository_ctx):
31    """Returns true if the host operating system is windows."""
32    os_name = repository_ctx.os.name.lower()
33    return os_name.find("windows") != -1
34
35
36def _execute(repository_ctx,
37             cmdline,
38             error_msg=None,
39             error_details=None,
40             empty_stdout_fine=False):
41    """Executes an arbitrary shell command.
42
43    Args:
44        repository_ctx: the repository_ctx object
45        cmdline: list of strings, the command to execute
46        error_msg: string, a summary of the error if the command fails
47        error_details: string, details about the error or steps to fix it
48        empty_stdout_fine: bool, if True, an empty stdout result is fine, otherwise
49        it's an error
50    Return:
51        the result of repository_ctx.execute(cmdline)
52  """
53    result = repository_ctx.execute(cmdline)
54    if result.stderr or not (empty_stdout_fine or result.stdout):
55        _fail("\n".join([
56            error_msg.strip() if error_msg else "Repository command failed",
57            result.stderr.strip(), error_details if error_details else ""
58        ]))
59    else:
60        return result
61
62
63def _read_dir(repository_ctx, src_dir):
64    """Returns a string with all files in a directory.
65
66  Finds all files inside a directory, traversing subfolders and following
67  symlinks. The returned string contains the full path of all files
68  separated by line breaks.
69  """
70    if _is_windows(repository_ctx):
71        src_dir = src_dir.replace("/", "\\")
72        find_result = _execute(
73            repository_ctx,
74            ["cmd.exe", "/c", "dir", src_dir, "/b", "/s", "/a-d"],
75            empty_stdout_fine=True)
76        # src_files will be used in genrule.outs where the paths must
77        # use forward slashes.
78        return find_result.stdout.replace("\\", "/")
79    else:
80        find_result = _execute(
81            repository_ctx, ["find", src_dir, "-follow", "-type", "f"],
82            empty_stdout_fine=True)
83        return find_result.stdout
84
85
86def _genrule(src_dir, genrule_name, command, outs):
87    """Returns a string with a genrule.
88
89  Genrule executes the given command and produces the given outputs.
90  """
91    return ('genrule(\n' + '    name = "' + genrule_name + '",\n' +
92            '    outs = [\n' + outs + '\n    ],\n' + '    cmd = """\n' +
93            command + '\n   """,\n' + ')\n')
94
95
96def _normalize_path(path):
97    """Returns a path with '/' and remove the trailing slash."""
98    path = path.replace("\\", "/")
99    if path[-1] == "/":
100        path = path[:-1]
101    return path
102
103
104def _symlink_genrule_for_dir(repository_ctx,
105                             src_dir,
106                             dest_dir,
107                             genrule_name,
108                             src_files=[],
109                             dest_files=[]):
110    """Returns a genrule to symlink(or copy if on Windows) a set of files.
111
112  If src_dir is passed, files will be read from the given directory; otherwise
113  we assume files are in src_files and dest_files
114  """
115    if src_dir != None:
116        src_dir = _normalize_path(src_dir)
117        dest_dir = _normalize_path(dest_dir)
118        files = '\n'.join(
119            sorted(_read_dir(repository_ctx, src_dir).splitlines()))
120        # Create a list with the src_dir stripped to use for outputs.
121        dest_files = files.replace(src_dir, '').splitlines()
122        src_files = files.splitlines()
123    command = []
124    outs = []
125    for i in range(len(dest_files)):
126        if dest_files[i] != "":
127            # If we have only one file to link we do not want to use the dest_dir, as
128            # $(@D) will include the full path to the file.
129            dest = '$(@D)/' + dest_dir + dest_files[i] if len(
130                dest_files) != 1 else '$(@D)/' + dest_files[i]
131            # On Windows, symlink is not supported, so we just copy all the files.
132            cmd = 'cp -f' if _is_windows(repository_ctx) else 'ln -s'
133            command.append(cmd + ' "%s" "%s"' % (src_files[i], dest))
134            outs.append('        "' + dest_dir + dest_files[i] + '",')
135    return _genrule(src_dir, genrule_name, " && ".join(command),
136                    "\n".join(outs))
137
138
139def _get_python_bin(repository_ctx):
140    """Gets the python bin path."""
141    python_bin = repository_ctx.os.environ.get(_PYTHON_BIN_PATH)
142    if python_bin != None:
143        return python_bin
144    python_bin_path = repository_ctx.which("python")
145    if python_bin_path != None:
146        return str(python_bin_path)
147    _fail("Cannot find python in PATH, please make sure " +
148          "python is installed and add its directory in PATH, or --define " +
149          "%s='/something/else'.\nPATH=%s" %
150          (_PYTHON_BIN_PATH, repository_ctx.os.environ.get("PATH", "")))
151
152
153def _get_bash_bin(repository_ctx):
154    """Gets the bash bin path."""
155    bash_bin = repository_ctx.os.environ.get(_BAZEL_SH)
156    if bash_bin != None:
157        return bash_bin
158    else:
159        bash_bin_path = repository_ctx.which("bash")
160        if bash_bin_path != None:
161            return str(bash_bin_path)
162        else:
163            _fail(
164                "Cannot find bash in PATH, please make sure " +
165                "bash is installed and add its directory in PATH, or --define "
166                + "%s='/path/to/bash'.\nPATH=%s" %
167                (_BAZEL_SH, repository_ctx.os.environ.get("PATH", "")))
168
169
170def _get_python_lib(repository_ctx, python_bin):
171    """Gets the python lib path."""
172    python_lib = repository_ctx.os.environ.get(_PYTHON_LIB_PATH)
173    if python_lib != None:
174        return python_lib
175    print_lib = (
176        "<<END\n" + "from __future__ import print_function\n" +
177        "import site\n" + "import os\n" + "\n" + "try:\n" +
178        "  input = raw_input\n" + "except NameError:\n" + "  pass\n" + "\n" +
179        "python_paths = []\n" + "if os.getenv('PYTHONPATH') is not None:\n" +
180        "  python_paths = os.getenv('PYTHONPATH').split(':')\n" + "try:\n" +
181        "  library_paths = site.getsitepackages()\n" +
182        "except AttributeError:\n" +
183        " from distutils.sysconfig import get_python_lib\n" +
184        " library_paths = [get_python_lib()]\n" +
185        "all_paths = set(python_paths + library_paths)\n" + "paths = []\n" +
186        "for path in all_paths:\n" + "  if os.path.isdir(path):\n" +
187        "    paths.append(path)\n" + "if len(paths) >=1:\n" +
188        "  print(paths[0])\n" + "END")
189    cmd = '%s - %s' % (python_bin, print_lib)
190    result = repository_ctx.execute([_get_bash_bin(repository_ctx), "-c", cmd])
191    return result.stdout.strip('\n')
192
193
194def _check_python_lib(repository_ctx, python_lib):
195    """Checks the python lib path."""
196    cmd = 'test -d "%s" -a -x "%s"' % (python_lib, python_lib)
197    result = repository_ctx.execute([_get_bash_bin(repository_ctx), "-c", cmd])
198    if result.return_code == 1:
199        _fail("Invalid python library path: %s" % python_lib)
200
201
202def _check_python_bin(repository_ctx, python_bin):
203    """Checks the python bin path."""
204    cmd = '[[ -x "%s" ]] && [[ ! -d "%s" ]]' % (python_bin, python_bin)
205    result = repository_ctx.execute([_get_bash_bin(repository_ctx), "-c", cmd])
206    if result.return_code == 1:
207        _fail("--define %s='%s' is not executable. Is it the python binary?" %
208              (_PYTHON_BIN_PATH, python_bin))
209
210
211def _get_python_include(repository_ctx, python_bin):
212    """Gets the python include path."""
213    result = _execute(
214        repository_ctx, [
215            python_bin, "-c", 'from __future__ import print_function;' +
216            'from distutils import sysconfig;' +
217            'print(sysconfig.get_python_inc())'
218        ],
219        error_msg="Problem getting python include path.",
220        error_details=(
221            "Is the Python binary path set up right? " + "(See ./configure or "
222            + _PYTHON_BIN_PATH + ".) " + "Is distutils installed?"))
223    return result.stdout.splitlines()[0]
224
225
226def _get_python_import_lib_name(repository_ctx, python_bin):
227    """Get Python import library name (pythonXY.lib) on Windows."""
228    result = _execute(
229        repository_ctx, [
230            python_bin, "-c",
231            'import sys;' + 'print("python" + str(sys.version_info[0]) + ' +
232            '      str(sys.version_info[1]) + ".lib")'
233        ],
234        error_msg="Problem getting python import library.",
235        error_details=("Is the Python binary path set up right? " +
236                       "(See ./configure or " + _PYTHON_BIN_PATH + ".) "))
237    return result.stdout.splitlines()[0]
238
239
240def _create_local_python_repository(repository_ctx):
241    """Creates the repository containing files set up to build with Python."""
242    python_bin = _get_python_bin(repository_ctx)
243    _check_python_bin(repository_ctx, python_bin)
244    python_lib = _get_python_lib(repository_ctx, python_bin)
245    _check_python_lib(repository_ctx, python_lib)
246    python_include = _get_python_include(repository_ctx, python_bin)
247    python_include_rule = _symlink_genrule_for_dir(
248        repository_ctx, python_include, 'python_include', 'python_include')
249    python_import_lib_genrule = ""
250    # To build Python C/C++ extension on Windows, we need to link to python import library pythonXY.lib
251    # See https://docs.python.org/3/extending/windows.html
252    if _is_windows(repository_ctx):
253        python_include = _normalize_path(python_include)
254        python_import_lib_name = _get_python_import_lib_name(
255            repository_ctx, python_bin)
256        python_import_lib_src = python_include.rsplit(
257            '/', 1)[0] + "/libs/" + python_import_lib_name
258        python_import_lib_genrule = _symlink_genrule_for_dir(
259            repository_ctx, None, '', 'python_import_lib',
260            [python_import_lib_src], [python_import_lib_name])
261    _tpl(
262        repository_ctx, "BUILD", {
263            "%{PYTHON_INCLUDE_GENRULE}": python_include_rule,
264            "%{PYTHON_IMPORT_LIB_GENRULE}": python_import_lib_genrule,
265        })
266
267
268def _create_remote_python_repository(repository_ctx, remote_config_repo):
269    """Creates pointers to a remotely configured repo set up to build with Python.
270  """
271    _tpl(repository_ctx, "remote.BUILD", {
272        "%{REMOTE_PYTHON_REPO}": remote_config_repo,
273    }, "BUILD")
274
275
276def _python_autoconf_impl(repository_ctx):
277    """Implementation of the python_autoconf repository rule."""
278    if _PYTHON_CONFIG_REPO in repository_ctx.os.environ:
279        _create_remote_python_repository(
280            repository_ctx, repository_ctx.os.environ[_PYTHON_CONFIG_REPO])
281    else:
282        _create_local_python_repository(repository_ctx)
283
284
285python_configure = repository_rule(
286    implementation=_python_autoconf_impl,
287    environ=[
288        _BAZEL_SH,
289        _PYTHON_BIN_PATH,
290        _PYTHON_LIB_PATH,
291        _PYTHON_CONFIG_REPO,
292    ],
293)
294"""Detects and configures the local Python.
295
296Add the following to your WORKSPACE FILE:
297
298```python
299python_configure(name = "local_config_python")
300```
301
302Args:
303  name: A unique name for this workspace rule.
304"""
305
306