[WIP] Allow to specify channels in a recipe

conda_build/metadata.py

@@ -23,7 +23,7 @@
 from conda_build import exceptions, utils, variants, environ
 from conda_build.conda_interface import memoized
 from conda_build.features import feature_list
-from conda_build.config import Config, get_or_merge_config
+from conda_build.config import Config, get_or_merge_config, get_channel_urls
 from conda_build.utils import (ensure_list, find_recipe, expand_globs, get_installed_packages,
                                HashableDict, insert_variant_versions)
 from conda_build.license_family import ensure_valid_license_family
@@ -390,6 +390,7 @@ def parse(data, config, path=None):
     'build/force_ignore_keys': list,
     'build/merge_build_host': bool,
     'build/msvc_compiler': text_type,
+    'requirements/channels': list,
     'requirements/build': list,
     'requirements/host': list,
     'requirements/run': list,
@@ -505,7 +506,7 @@ def _str_version(package_meta):
               },
     'outputs': {'name', 'version', 'number', 'script', 'script_interpreter', 'build',
                 'requirements', 'test', 'about', 'files', 'type'},
-    'requirements': {'build', 'host', 'run', 'conflicts', 'run_constrained'},
+    'requirements': {'channels', 'build', 'host', 'run', 'conflicts', 'run_constrained'},
     'app': {'entry', 'icon', 'summary', 'type', 'cli_opts',
             'own_environment'},
     'test': {'requires', 'commands', 'files', 'imports', 'source_files', 'downstreams'},
@@ -965,6 +966,10 @@ def parse_again(self, permit_undefined_jinja=False, allow_no_other_outputs=False
         if self.meta.get('build', {}).get('error_overdepending', False):
             self.config.error_overdepending = self.meta['build']['error_overdepending']
 
+        additional_channels = ensure_list(self.get_value('requirements/channels') or [])
+        if additional_channels:
+            self._add_channels_to_config(additional_channels)
+
         self.validate_features()
         self.ensure_no_pip_requirements()
 
@@ -1156,6 +1161,11 @@ def build_number(self):
             build_int = ""
         return build_int
 
+    def _add_channels_to_config(self, channels):
+        for url in get_channel_urls({'channels': channels}):
+            if url not in self.config.channel_urls:
+                self.config.channel_urls.append(url)
+
     def get_depends_top_and_out(self, typ):
         meta_requirements = ensure_list(self.get_value('requirements/' + typ, []))[:]
         req_names = set(req.split()[0] for req in meta_requirements if req)

news/allow-channels-in-recipes.rst

@@ -0,0 +1,25 @@
+Enhancements:
+-------------
+
+* Channels can now be added to recipes (at requirements > channels).
+
+Bug fixes:
+----------
+
+* <news item>
+
+Deprecations:
+-------------
+
+* <news item>
+
+Docs:
+-----
+
+* <news item>
+
+Other:
+------
+
+* <news item>
+

tests/test-recipes/metadata/_recipe_requiring_external_channel_in_yaml/meta.yaml

@@ -0,0 +1,11 @@
+package:
+  name: requires_external_channel
+  version: 1.0
+
+requirements:
+  channels:
+    - conda_build_test
+
+  build:
+    # package that does not exist on defaults, but only on our test channel
+    - conda_build_test_requirement

tests/test_cli.py

@@ -49,6 +49,23 @@ def test_build_add_channel():
     main_build.execute(args)
 
 
+def test_build_add_channel_from_yaml():
+    """This recipe requires the conda_build_test_requirement package, which is
+    only on the conda_build_test channel. This verifies that specifying channels in the meta.yaml file works."""
+
+    args = [os.path.join(metadata_dir, "_recipe_requiring_external_channel_in_yaml")]
+    main_build.execute(args)
+
+
+def test_build_duplicate_channel():
+    """This recipe requires the conda_build_test_requirement package, which is
+    only on the conda_build_test channel. This verifies that specifying channels in the meta.yaml and using the -c argument simultaneously does not cause problems."""
+
+    args = ['-c', 'conda_build_test', '--no-activate', '--no-anaconda-upload', 
+            os.path.join(metadata_dir, "_recipe_requiring_external_channel_in_yaml")]
+    main_build.execute(args)
+
+
 def test_build_without_channel_fails(testing_workdir):
     # remove the conda forge channel from the arguments and make sure that we fail.  If we don't,
     #    we probably have channels in condarc, and this is not a good test.
@@ -76,6 +93,22 @@ def test_render_add_channel():
         assert required_package_details[1] == '1.0', "Expected version number 1.0 on successful rendering, but got {}".format(required_package_details[1])
 
 
+def test_render_add_channel_from_yaml():
+    """This recipe requires the conda_build_test_requirement package, which is
+    only on the conda_build_test channel. This verifies specifying channels in the meta.yaml file works for rendering."""
+    with TemporaryDirectory() as tmpdir:
+        rendered_filename = os.path.join(tmpdir, 'out.yaml')
+        args = [os.path.join(metadata_dir, "_recipe_requiring_external_channel_in_yaml"), '--file', rendered_filename]
+        main_render.execute(args)
+        rendered_meta = yaml.safe_load(open(rendered_filename, 'r'))
+        required_package_string = [pkg for pkg in rendered_meta['requirements']['build'] if
+                                   'conda_build_test_requirement' in pkg][0]
+        required_package_details = required_package_string.split(' ')
+        assert len(required_package_details) > 1, ("Expected version number on successful "
+                                    "rendering, but got only {}".format(required_package_details))
+        assert required_package_details[1] == '1.0', "Expected version number 1.0 on successful rendering, but got {}".format(required_package_details[1])
+
+
 def test_render_without_channel_fails():
     # do make extra channel available, so the required package should not be found
     with TemporaryDirectory() as tmpdir: