Commit f2632d59 authored by Jonathan Maw's avatar Jonathan Maw
Browse files

source: Store the url aliases or use an override 

This is part of a later plan to implement mirroring without forcing
everyone to update their sources. We use the expected calls to
Source.translate_url() when running Source.configure() to extract the
aliases from the URL. Multiple aliases must be extracted because
sources exist that may fetch from multiple aliases (for example, git
submodules)

Later, we want to substitute another URI where the alias normally reads
from the project - We accomplish this by re-instantiating the Source
with the alias overrides passed as an argument to the constructor.
parent a75928e9

buildstream/source.py

+53 −4
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ class Source(Plugin): 
    __defaults = {}          # The defaults from the project

    __defaults_set = False   # Flag, in case there are not defaults at all



    def __init__(self, context, project, meta):

    def __init__(self, context, project, meta, *, alias_overrides=None):

        provenance = _yaml.node_get_provenance(meta.config)

        super().__init__("{}-{}".format(meta.element_name, meta.element_index),

                         context, project, provenance, "source")
@@ -134,6 +134,8 @@ class Source(Plugin): 
        self.__element_kind = meta.element_kind         # The kind of the element owning this source

        self.__directory = meta.directory               # Staging relative directory

        self.__consistency = Consistency.INCONSISTENT   # Cached consistency state

        self.__alias_override = alias_override          # Tuple of alias and its override to use instead

        self.__expected_alias = None                    # A hacky way to store the first alias used



        # Collect the composited element configuration and

        # ask the element to configure itself.
@@ -283,6 +285,18 @@ class Source(Plugin): 
        """

        self.stage(directory)



    def mark_download_url(self, url):

        """Identifies the URL that this Source uses to download



        This must be called during :func:`~buildstream.plugin.Plugin.configure` if

        :func:`~buildstream.source.Source.translate_url` is not called.



        Args:

           url (str): The url used to download

        """

        alias, _ = url.split(utils._ALIAS_SEPARATOR, 1)

        self.__expected_alias = alias



    #############################################################

    #                       Public Methods                      #

    #############################################################
@@ -299,16 +313,40 @@ class Source(Plugin): 
        os.makedirs(directory, exist_ok=True)

        return directory



    def translate_url(self, url):

    def translate_url(self, url, alias_override=None):

        """Translates the given url which may be specified with an alias

        into a fully qualified url.



        Args:

           url (str): A url, which may be using an alias

           alias_override (str): Optionally, an URI to override the alias with.



        Returns:

           str: The fully qualified url, with aliases resolved

        """

        # Alias overriding can happen explicitly (by command-line) or

        # implicitly (the Source being constructed with an __alias_override).

        if alias_override or self.__alias_override:

            url_alias, url_body = url.split(utils._ALIAS_SEPARATOR, 1)

            if url_alias:

                if alias_override:

                    url = alias_override + url_body

                else:

                    # Implicit alias overrides may only be done for one

                    # specific alias, so that sources that fetch from multiple

                    # URLs and use different aliases default to only overriding

                    # one alias, rather than getting confused.

                    override_alias = self.__alias_override[0]

                    override_url = self.__alias_override[1]

                    if url_alias == override_alias:

                        url = override_url + url_body

            return url

        else:

            # Sneakily store the alias if it hasn't already been stored

            if not self.__expected_alias and url and utils._ALIAS_SEPARATOR in url:

                url_alias, _ = url.split(utils._ALIAS_SEPARATOR, 1)

                self.__expected_alias = url_alias



            project = self._get_project()

            return project.translate_url(url)
@@ -593,6 +631,17 @@ class Source(Plugin): 


        return new_ref



    # Returns the alias if it's defined in the project

    def _get_alias(self):

        alias = self.__expected_alias

        project = self._get_project()

        if project.get_alias_uri(alias):

            # The alias must already be defined in the project's aliases

            # otherwise http://foo gets treated like it contains an alias

            return alias

        else:

            return None



    #############################################################

    #                   Local Private Methods                   #

    #############################################################