sources: introduce per-source content_type

Introduce a new class member `content_type` that specifies what type of
items the source will store in the cache. Use that to generalize the
setup step, which is shared across all sources.

osbuild/sources.py

@@ -3,6 +3,7 @@ import contextlib
 import os
 import json
 import tempfile
+from abc import abstractmethod
 
 from . import host
 from .objectstore import ObjectStore
@@ -54,12 +55,19 @@ class SourceService(host.Service):
     def download(self, items, cache, options):
         pass
 
-    def setup(self, cache, content_type):
-        self.cache = os.path.join(cache, content_type)
+    @property
+    @classmethod
+    @abstractmethod
+    def content_type(cls):
+        """The content type of the source."""
+
+    def setup(self, args):
+        self.cache = os.path.join(args["cache"], self.content_type)
         os.makedirs(self.cache, exist_ok=True)
 
     def dispatch(self, method: str, args, fds):
         if method == "download":
+            self.setup(args)
             with os.fdopen(fds.steal(0)) as f:
                 items = json.load(f)
 

sources/org.osbuild.curl

@@ -165,8 +165,9 @@ def download(items, cache):
 
 class CurlSource(sources.SourceService):
 
-    def download(self, items, cache, _options):
-        self.setup(cache, "org.osbuild.files")
+    content_type = "org.osbuild.files"
+
+    def download(self, items, _cache, _options):
         download(items, self.cache)
 
 

sources/org.osbuild.inline

@@ -81,9 +81,10 @@ def process(items: Dict, cache: str, tmpdir):
 
 class InlineSource(sources.SourceService):
 
-    def download(self, items, cache, _options):
-        self.setup(cache, "org.osbuild.files")
-        with tempfile.TemporaryDirectory(prefix=".unverified-", dir=cache) as tmpdir:
+    content_type = "org.osbuild.files"
+
+    def download(self, items, _cache, _options):
+        with tempfile.TemporaryDirectory(prefix=".unverified-", dir=self.cache) as tmpdir:
             process(items, self.cache, tmpdir)
 
 

sources/org.osbuild.ostree

@@ -114,8 +114,9 @@ def download(items, cache):
 
 class OSTreeSource(sources.SourceService):
 
-    def download(self, items, cache, _options):
-        self.setup(cache, "org.osbuild.ostree")
+    content_type = "org.osbuild.ostree"
+
+    def download(self, items, _cache, _options):
 
         download(items, self.cache)
 

sources/org.osbuild.skopeo

@@ -118,8 +118,9 @@ def download(items, cache):
 
 class SkopeoSource(sources.SourceService):
 
-    def download(self, items, cache, _options):
-        self.setup(cache, "org.osbuild.containers")
+    content_type = "org.osbuild.containers"
+
+    def download(self, items, _cache, _options):
 
         download(items, self.cache)