Add content reader to decouple NFS file reads [RHELDST-26339]

src/pushsource/_impl/list_cmd.py

@@ -48,6 +48,10 @@ def represent_enum(cls, dumper: yaml.Dumper, value: enum.Enum):
         # same as a plain string "foo".
         return dumper.represent_data(value.value)
 
+    @classmethod
+    def represent_callable(cls, dumper: yaml.Dumper, value: callable):
+        return dumper.represent_data(getattr(value, "__name__", repr(value)))
+
     @classmethod
     def add_enum_representers(cls):
         # Register our enum representer for any enum classes in the API.
@@ -59,6 +63,7 @@ def add_enum_representers(cls):
 
 ItemDumper.add_enum_representers()
 ItemDumper.add_representer(frozendict, ItemDumper.represent_dict)
+ItemDumper.add_representer(type(lambda: None), ItemDumper.represent_callable)
 
 
 def format_python(item):

src/pushsource/_impl/model/base.py

@@ -16,6 +16,8 @@
     optional,
     optional_str,
 )
+from ..reader import PushItemReader
+from ..utils.openers import open_src_local
 
 
 LOG = logging.getLogger("pushsource")
@@ -178,6 +180,10 @@ def _default_build_info(self):
     doesn't enforce this.
     """
 
+    opener = attr.ib(type=callable, default=open_src_local, repr=False)
+    """Callable that gets the content of this push item. The content could be
+    retrived from `content()` method"""
+
     def with_checksums(self):
         """Return a copy of this push item with checksums present.
 
@@ -248,3 +254,12 @@ def with_checksums(self):
             updated_sums[attribute] = hasher.hexdigest()
 
         return attr.evolve(self, **updated_sums)
+
+    def content(self):
+        """Returns a read-only, non-seekable content of this push item.
+
+        Returns:
+            :class:`~io.BufferedReader`
+                A non-seekable object of the push item content
+        """
+        return PushItemReader(self.opener(self))

src/pushsource/_impl/reader.py

@@ -0,0 +1,23 @@
+from io import BufferedReader, SEEK_SET, UnsupportedOperation
+
+
+class PushItemReader(BufferedReader):
+    # Internal class to ensure that the file-like content object returned by
+    # the push items are read-only and non-seekable with a name attribute.
+    def __init__(self, raw, name=None, **kwargs):
+        super(PushItemReader, self).__init__(raw, **kwargs)
+
+        # Attempt to assign name from the raw object if none is provided
+        self._name = name or getattr(super(), "name", None)
+        if not self._name:
+            raise ValueError("'name' not provided or availble from 'raw' object")
+
+    @property
+    def name(self):
+        return self._name or super().name()
+
+    def seekable(self):
+        return False
+
+    def seek(self, offset, whence=SEEK_SET):
+        raise UnsupportedOperation(f"Seek unsupported while reading {self.name}")

src/pushsource/_impl/utils/openers.py

@@ -0,0 +1,5 @@
+def open_src_local(item):
+    # default opener for the push items
+    # assumes that the item's 'src' points to the
+    # locally-accessible file
+    return open(item.src, "rb")

tests/baseline/cases/direct-cgw.yml

@@ -15,6 +15,7 @@ items:
     - dest
     md5sum: null
     name: cgw.yaml
+    opener: open_src_local
     origin: direct
     sha256sum: null
     signing_key: null

tests/baseline/cases/direct-comps.yml

@@ -14,6 +14,7 @@ items:
     dest: []
     md5sum: null
     name: mycomps.xml
+    opener: open_src_local
     origin: direct
     sha256sum: null
     signing_key: null

tests/baseline/cases/direct-dir.yml

@@ -15,6 +15,7 @@ items:
     - /destdir
     md5sum: null
     name: srcdir
+    opener: open_src_local
     origin: direct
     sha256sum: null
     signing_key: null

tests/baseline/cases/direct-file.yml

@@ -18,6 +18,7 @@ items:
     display_order: null
     md5sum: null
     name: custom-filename
+    opener: open_src_local
     origin: direct
     sha256sum: null
     signing_key: null

tests/baseline/cases/direct-modulemd-src.yml

@@ -14,6 +14,7 @@ items:
     dest: []
     md5sum: null
     name: modules.src.txt
+    opener: open_src_local
     origin: direct
     sha256sum: null
     signing_key: null

tests/baseline/cases/direct-modulemd.yml

@@ -14,6 +14,7 @@ items:
     dest: []
     md5sum: null
     name: my-best-module
+    opener: open_src_local
     origin: direct
     sha256sum: null
     signing_key: null

tests/baseline/cases/direct-productid.yml

@@ -17,6 +17,7 @@ items:
     - repo3
     md5sum: null
     name: some-cert
+    opener: open_src_local
     origin: direct
     products:
     - architecture:

tests/baseline/cases/direct-rpm.yml

@@ -15,6 +15,7 @@ items:
     md5sum: null
     module_build: null
     name: test.rpm
+    opener: open_src_local
     origin: custom-origin
     sha256sum: null
     signing_key: A1B2C3