Move the config flow control of the linux build into Python

The use of separate bash processes for each build means we can be a bit
freer with environment pollution

cibuildwheel/linux.py

@@ -30,6 +30,22 @@ def get_python_configurations(build_selector):
     return [c for c in python_configurations if build_selector(c.identifier)]
 
 
+def run_docker(command, stdin_str=None):
+    print('docker command: docker {}'.format(' '.join(map(shlex_quote, command))))
+    if stdin_str is None:
+        subprocess.check_call(['docker'] + command)
+    else:
+        args = ['docker'] + command
+        process = subprocess.Popen(args, stdin=subprocess.PIPE, universal_newlines=True)
+        try:
+            process.communicate(stdin_str)
+        except KeyboardInterrupt:
+            process.kill()
+            process.wait()
+        if process.returncode != 0:
+            raise subprocess.CalledProcessError(process.returncode, args)
+
+
 def build(project_dir, output_dir, test_command, test_requires, test_extras, before_build, build_verbosity, build_selector, repair_command, environment, manylinux_images, dependency_constraints):
     try:
         subprocess.check_call(['docker', '--version'])
@@ -51,23 +67,43 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
         if not platform_configs:
             continue
 
-        bash_script = '''
+        container_name = 'cibuildwheel-{}'.format(uuid.uuid4())
+        try:
+            run_docker(['create',
+                        '--env', 'CIBUILDWHEEL',
+                        '--name', container_name,
+                        '-i',
+                        '-v', '/:/host', # ignored on CircleCI
+                        docker_image, '/bin/bash'])
+            run_docker(['cp', os.path.abspath(project_dir) + '/.', container_name + ':/project'])
+
+            for config in platform_configs:
+                if dependency_constraints:
+                    run_docker(['cp', os.path.abspath(dependency_constraints), container_name + ':/constraints.txt'])
+                run_docker(['start', '-i', '-a', container_name], stdin_str='''
                     set -o errexit
                     set -o xtrace
-            mkdir /output
+                    mkdir -p /output
                     cd /project
 
+                    PYBIN="{config_python_bin}"
+                    export PATH="$PYBIN:$PATH"
+
+                    # check the active python and pip are in PYBIN
+                    # if `test` returns false, the script will exit due to errexit
+                    test "$(which pip)" = "$PYBIN/pip"
+                    test "$(which python)" = "$PYBIN/python"
+
                     {environment_exports}
 
-            for PYBIN in {pybin_paths}; do
                     if [ ! -z {before_build} ]; then
-                    PATH="$PYBIN:$PATH" sh -c {before_build}
+                        sh -c {before_build}
                     fi
 
                     # Build the wheel
                     rm -rf /tmp/built_wheel
                     mkdir /tmp/built_wheel
-                PATH="$PYBIN:$PATH" "$PYBIN/pip" wheel . -w /tmp/built_wheel --no-deps {build_verbosity_flag}
+                    pip wheel . -w /tmp/built_wheel --no-deps {build_verbosity_flag}
                     built_wheel=(/tmp/built_wheel/*.whl)
 
                     # repair the wheel
@@ -86,9 +122,9 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
                     if [ ! -z {test_command} ]; then
                         # Set up a virtual environment to install and test from, to make sure
                         # there are no dependencies that were pulled in at build time.
-                    "$PYBIN/pip" install {dependency_install_flags} virtualenv
+                        pip install {dependency_install_flags} virtualenv
                         venv_dir=`mktemp -d`/venv
-                    "$PYBIN/python" -m virtualenv "$venv_dir"
+                        python -m virtualenv "$venv_dir"
 
                         # run the tests in a subshell to keep that `activate`
                         # script from polluting the env
@@ -126,10 +162,11 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
 
                     # we're all done here; move it to output
                     mv "${{repaired_wheels[@]}}" /output
-                for repaired_wheel in "${{repaired_wheels[@]}}"; do chown {uid}:{gid} "/output/$(basename "$repaired_wheel")"; done
+                    for repaired_wheel in "${{repaired_wheels[@]}}"; do
+                        chown {uid}:{gid} "/output/$(basename "$repaired_wheel")"
                     done
                 '''.format(
-            pybin_paths=' '.join(c.path+'/bin' for c in platform_configs),
+                    config_python_bin=config.path + '/bin',
                     test_requires=' '.join(test_requires),
                     test_extras=test_extras,
                     test_command=shlex_quote(
@@ -146,38 +183,14 @@ def build(project_dir, output_dir, test_command, test_requires, test_extras, bef
                     uid=os.getuid(),
                     gid=os.getgid(),
                     dependency_install_flags='-c /constraints.txt' if dependency_constraints else '',
-        )
+                ))
 
-        def run_docker(command, stdin_str=None):
+            # copy the output back into the host
-            print('docker command: docker {}'.format(' '.join(map(shlex_quote, command))))
-            if stdin_str is None:
-                subprocess.check_call(['docker'] + command)
-            else:
-                args = ['docker'] + command
-                process = subprocess.Popen(args, stdin=subprocess.PIPE, universal_newlines=True)
-                try:
-                    process.communicate(stdin_str)
-                except KeyboardInterrupt:
-                    process.kill()
-                    process.wait()
-                if process.returncode != 0:
-                    raise subprocess.CalledProcessError(process.returncode, args)
-
-        container_name = 'cibuildwheel-{}'.format(uuid.uuid4())
-        try:
-            run_docker(['create',
-                        '--env', 'CIBUILDWHEEL',
-                        '--name', container_name,
-                        '-i',
-                        '-v', '/:/host', # ignored on Circle
-                        docker_image, '/bin/bash'])
-            run_docker(['cp', os.path.abspath(project_dir) + '/.', container_name + ':/project'])
-            if dependency_constraints:
-                run_docker(['cp', os.path.abspath(dependency_constraints), container_name + ':/constraints.txt'])
-            run_docker(['start', '-i', '-a', container_name], stdin_str=bash_script)
             run_docker(['cp', container_name + ':/output/.', os.path.abspath(output_dir)])
         except subprocess.CalledProcessError:
             exit(1)
         finally:
             # Still gets executed, even when 'exit(1)' gets called
             run_docker(['rm', '--force', '-v', container_name])
+
+