Add support for mesa libraries.

Currently Snapcraft adds only a few standard paths to
LD_LIBRARY_PATH. This commit expands that to include
paths used by mesa packages.

Also add an opencv example to exercise this.

Signed-off-by: Kyle Fazzari <kyle@canonical.com>

examples/opencv/snapcraft.yaml

@@ -0,0 +1,14 @@
+name: opencv-example
+version: 1.0
+summary: Use OpenCV and OpenGL
+description: A simple OpenCV example
+
+binaries:
+  example:
+    exec: bin/example
+
+parts:
+  example:
+    plugin: cmake
+    source: src
+    stage-packages: [libopencv-dev]

examples/opencv/src/CMakeLists.txt

@@ -0,0 +1,10 @@
+cmake_minimum_required(VERSION 2.6)
+project(example)
+
+find_package(OpenCV REQUIRED)
+
+add_executable(example main.cpp)
+
+target_link_libraries(example ${OpenCV_LIBS})
+
+install(TARGETS example RUNTIME DESTINATION bin)

examples/opencv/src/main.cpp

@@ -0,0 +1,15 @@
+#include <iostream>
+
+#include <opencv2/core/core.hpp>
+
+int main()
+{
+    cv::Mat matrix(2, 2, CV_8UC1);
+
+    matrix.at<uint8_t>(cv::Point(0, 0)) = 1;
+    matrix.at<uint8_t>(cv::Point(0, 1)) = 2;
+    matrix.at<uint8_t>(cv::Point(1, 0)) = 3;
+    matrix.at<uint8_t>(cv::Point(1, 1)) = 4;
+
+    std::cout << matrix << std::endl;
+}

examples_tests/tests.py

@@ -125,6 +125,11 @@ class TestSnapcraftExamples(testscenarios.TestWithScenarios):
                  'custom libpipeline called\n'
                  'include\n')],
             }),
+        ('opencv', {
+            'dir': 'opencv',
+            'name': 'opencv-example',
+            'version': '1.0',
+            }),
         ('py2-project', {
             'dir': 'py2-project',
             'name': 'spongeshaker',

snapcraft/tests/test_yaml.py

@@ -22,6 +22,7 @@
 
 import fixtures
 
+import snapcraft.common
 import snapcraft.yaml
 from snapcraft import (
     dirs,
@@ -346,6 +347,107 @@ def test_config_expands_filesets(self, mock_loadPlugin):
         })
 
 
+class TestYamlEnvironment(tests.TestCase):
+
+    def setUp(self):
+        super().setUp()
+        dirs.setup_dirs()
+
+        tempdirObj = tempfile.TemporaryDirectory()
+        self.addCleanup(tempdirObj.cleanup)
+        os.chdir(tempdirObj.name)
+        with open('icon.svg', 'w') as icon:
+            icon.write('<svg />')
+
+        with open('snapcraft.yaml', 'w') as fp:
+            fp.write("""name: test
+version: "1"
+summary: test
+description: test
+icon: icon.svg
+
+parts:
+  part1:
+    plugin: go
+    stage-packages: [fswebcam]
+""")
+
+    def test_config_runtime_environment(self):
+        config = snapcraft.yaml.Config()
+        environment = config.runtime_env('foo')
+        self.assertTrue('PATH="foo/bin:foo/usr/bin:$PATH"' in environment)
+
+        # Ensure that LD_LIBRARY_PATH is present and it contains only the
+        # basics.
+        paths = []
+        for variable in environment:
+            if 'LD_LIBRARY_PATH' in variable:
+                these_paths = variable.split('=')[1].strip()
+                paths.extend(these_paths.replace('"', '').split(':'))
+
+        self.assertTrue(len(paths) > 0,
+                        'Expected LD_LIBRARY_PATH to be in environment')
+
+        arch = snapcraft.common.get_arch_triplet()
+        for expected in ['foo/lib', 'foo/usr/lib', 'foo/lib/{}'.format(arch),
+                         'foo/usr/lib/{}'.format(arch)]:
+            self.assertTrue(expected in paths,
+                            'Expected LD_LIBRARY_PATH to include "{}"'.format(
+                                expected))
+
+    def test_config_runtime_environment_ld(self):
+        # Place a few ld.so.conf files in supported locations. We expect the
+        # contents of these to make it into the LD_LIBRARY_PATH.
+        os.makedirs('foo/usr/lib/my_arch/mesa/')
+        with open('foo/usr/lib/my_arch/mesa/ld.so.conf', 'w') as f:
+            f.write('/mesa')
+
+        os.makedirs('foo/usr/lib/my_arch/mesa-egl/')
+        with open('foo/usr/lib/my_arch/mesa-egl/ld.so.conf', 'w') as f:
+            f.write('# Standalone comment\n')
+            f.write('/mesa-egl')
+
+        config = snapcraft.yaml.Config()
+        environment = config.runtime_env('foo')
+
+        # Ensure that the LD_LIBRARY_PATH includes all the above paths
+        paths = []
+        for variable in environment:
+            if 'LD_LIBRARY_PATH' in variable:
+                these_paths = variable.split('=')[1].strip()
+                paths.extend(these_paths.replace('"', '').split(':'))
+
+        self.assertTrue(len(paths) > 0,
+                        'Expected LD_LIBRARY_PATH to be in environment')
+
+        for expected in ['foo/mesa', 'foo/mesa-egl']:
+            self.assertTrue(expected in paths,
+                            'Expected LD_LIBRARY_PATH to include "{}"'.format(
+                                expected))
+
+
+class TestLdLibraryPathParser(tests.TestCase):
+
+    def _write_conf_file(self, contents):
+        tmp = tempfile.NamedTemporaryFile(delete=False, mode='w')
+        self.addCleanup(os.remove, tmp.name)
+
+        tmp.write(contents)
+        tmp.close()
+
+        return tmp.name
+
+    def test_extract_ld_library_paths(self):
+        file_path = self._write_conf_file("""# This is a comment
+/foo/bar
+/colon:/separated,/comma\t/tab /space # This is another comment
+/baz""")
+
+        self.assertEqual(['/foo/bar', '/colon', '/separated', '/comma',
+                          '/tab', '/space', '/baz'],
+                         snapcraft.yaml._extract_ld_library_paths(file_path))
+
+
 class TestValidation(tests.TestCase):
 
     def setUp(self):

snapcraft/yaml.py

@@ -20,6 +20,8 @@
 import os
 import os.path
 import sys
+import re
+import glob
 
 import jsonschema
 import yaml
@@ -205,13 +207,22 @@ def runtime_env(self, root):
             '{0}/usr/bin',
             '$PATH'
         ]).format(root) + '"')
+
+        # Add the default LD_LIBRARY_PATH
         env.append('LD_LIBRARY_PATH="' + ':'.join([
             '{0}/lib',
             '{0}/usr/lib',
             '{0}/lib/{1}',
             '{0}/usr/lib/{1}',
             '$LD_LIBRARY_PATH'
         ]).format(root, common.get_arch_triplet()) + '"')
+
+        # Add more specific LD_LIBRARY_PATH if necessary
+        ld_library_paths = _determine_ld_library_path(root)
+        if ld_library_paths:
+            env.append('LD_LIBRARY_PATH="' + ':'.join(ld_library_paths) +
+                       ':$LD_LIBRARY_PATH"')
+
         return env
 
     def build_env(self, root):
@@ -292,6 +303,38 @@ def snap_env(self):
         return env
 
 
+def _determine_ld_library_path(root):
+    # If more ld.so.conf files need to be supported, add them here.
+    ld_config_globs = {
+        '{}/usr/lib/*/mesa*/ld.so.conf'.format(root)
+    }
+
+    ld_library_paths = []
+    for this_glob in ld_config_globs:
+        for ld_conf_file in glob.glob(this_glob):
+            ld_library_paths.extend(_extract_ld_library_paths(ld_conf_file))
+
+    return [root + path for path in ld_library_paths]
+
+
+def _extract_ld_library_paths(ld_conf_file):
+    # From the ldconfig manpage, paths can be colon-, space-, tab-, newline-,
+    # or comma-separated.
+    path_delimiters = re.compile(r'[:\s,]')
+    comments = re.compile(r'#.*$')
+
+    paths = []
+    with open(ld_conf_file, 'r') as f:
+        for line in f:
+            # Remove comments from line
+            line = comments.sub('', line).strip()
+
+            if line:
+                paths.extend(path_delimiters.split(line))
+
+    return paths
+
+
 def _validate_snapcraft_yaml(snapcraft_yaml):
     schema_file = os.path.abspath(os.path.join(common.get_schemadir(),
                                                'snapcraft.yaml'))