Sketch to show that populating download cache on conan upload is possible

conan/cli/commands/upload.py

@@ -1,3 +1,5 @@
+import os
+
 from conan.api.conan_api import ConanAPI
 from conan.api.model import ListPattern, MultiPackagesList
 from conan.api.output import ConanOutput

conan/internal/conan_app.py

@@ -38,6 +38,7 @@ def __init__(self, requester, cmd_wrapper, global_conf, cache):
 
 class ConanApp(object):
     def __init__(self, cache_folder, global_conf):
+        self.global_conf = global_conf
 
         self.cache_folder = cache_folder
         self.cache = ClientCache(self.cache_folder, global_conf)

conans/client/cmd/uploader.py

@@ -4,12 +4,14 @@
 
 from conan.internal.conan_app import ConanApp
 from conan.api.output import ConanOutput
+from conans.client.downloaders.download_cache import DownloadCache
 from conans.client.source import retrieve_exports_sources
 from conans.errors import ConanException, NotFoundException
 from conans.paths import (CONAN_MANIFEST, CONANFILE, EXPORT_SOURCES_TGZ_NAME,
                           EXPORT_TGZ_NAME, PACKAGE_TGZ_NAME, CONANINFO)
 from conans.util.files import (clean_dirty, is_dirty, gather_files,
-                               gzopen_without_timestamps, set_dirty_context_manager, mkdir)
+                               gzopen_without_timestamps, set_dirty_context_manager, mkdir,
+                               remove_if_dirty)
 
 UPLOAD_POLICY_FORCE = "force-upload"
 UPLOAD_POLICY_SKIP = "skip-upload"
@@ -232,6 +234,9 @@ def upload_recipe(self, ref, bundle, remote):
 
         duration = time.time() - t1
         self._output.debug(f"Upload {ref} in {duration} time")
+        for cache_file in cache_files.items():
+            self._local_cache_recipe_file(ref, cache_file, remote)
+
         return ref
 
     def upload_package(self, pref, prev_bundle, remote):
@@ -244,6 +249,37 @@ def upload_package(self, pref, prev_bundle, remote):
         self._app.remote_manager.upload_package(pref, cache_files, remote)
         duration = time.time() - t1
         self._output.debug(f"Upload {pref} in {duration} time")
+        for cache_file in cache_files.items():
+            self._local_cache_package_file(pref, cache_file, remote)
+
+    def _local_cache_recipe_file(self, ref, cache_file, remote):
+        approved_files = ["conanfile.py", "conan_export.tgz", "conanmanifest.txt"]
+        filename, path = cache_file
+        if filename not in approved_files:
+            return
+        _download_cache = self._app.global_conf.get("core.download:download_cache")
+        url = self._app.remote_manager._auth_manager._get_rest_client(remote)._get_api().router.recipe_file(ref, filename)
+        self._cache_local_upload_url(url, path)
+
+    def _local_cache_package_file(self, pref, cache_file, remote):
+        approved_files = ["conaninfo.txt", "conan_package.tgz", "conanmanifest.txt"]
+        filename, path = cache_file
+        if filename not in approved_files:
+            return
+        url = self._app.remote_manager._auth_manager._get_rest_client(remote)._get_api().router.package_file(pref, filename)
+        self._cache_local_upload_url(url, path)
+
+    def _cache_local_upload_url(self, url, path):
+        _download_cache = self._app.global_conf.get("core.download:download_cache")
+        if _download_cache and os.path.isabs(_download_cache):
+            download_cache = DownloadCache(_download_cache)
+            cached_path, h = download_cache.cached_path(url)
+            with download_cache.lock(h):
+                remove_if_dirty(cached_path)
+                with set_dirty_context_manager(cached_path):
+                    shutil.copy2(path, cached_path)
+                    self._output.info(
+                        f"Caching {path} to local cache '{cached_path}' - was uploaded to {url}")
 
 
 def compress_files(files, name, dest_dir, compresslevel=None, ref=None):

conans/test/integration/command/upload/upload_test.py

@@ -14,7 +14,8 @@
 from conans.paths import EXPORT_SOURCES_TGZ_NAME, PACKAGE_TGZ_NAME
 from conans.test.utils.tools import NO_SETTINGS_PACKAGE_ID, TestClient, TestServer, \
     TurboTestClient, GenConanfile, TestRequester, TestingResponse
-from conans.util.files import gzopen_without_timestamps, is_dirty, save, set_dirty
+from conans.test.utils.test_files import temp_folder
+from conans.util.files import gzopen_without_timestamps, is_dirty, save, set_dirty, load
 
 conanfile = """from conan import ConanFile
 from conan.tools.files import copy
@@ -231,10 +232,14 @@ def test_upload_unmodified_package(self):
 
         client.save({"conanfile.py": conanfile,
                      "hello.cpp": ""})
+        download_cache = temp_folder()
+        client.save_home({"global.conf": f"core.download:download_cache={download_cache}"})
         ref = RecipeReference.loads("hello0/1.2.1@frodo/stable")
         client.run("create . --user=frodo --channel=stable")
         client.run("upload hello0/1.2.1@frodo/stable -r default")
 
+        assert len(os.listdir(os.path.join(download_cache, "c"))) == 5
+
         client2 = TestClient(servers=client.servers, inputs=["admin", "password"])
         client2.save({"conanfile.py": conanfile,
                       "hello.cpp": ""})