frontend: point Copr repositories to Pulp

Fix fedora-copr#3375

Of course only for Copr projects that has configured to have their
storage in Pulp, not all Copr projects.

There are three possible options how to implement this.

1. The Most straightforward is to not generate repofiles ourselves and let Pulp
   do it. The downside is that we would have to pass additional parameters (it
   is possible though) such as repo priority, module hotfixes attribute, etc,
   and figure out how to count repo downloads
2. Generate repofiles ourselves, only point to `baseurl` in Pulp. This IMHO the
   best option for keeping compatibility between storage on the backend and in
   Pulp, so I implement this option in this PR.
3. Adding a Lighttpd redirect for `baseurl` of the Pulp-stored projects to Pulp
   content URL. This will be needed in the future to ensure that users don't
   have to re-enable Copr repositories, once those projects are migrated to
   Pulp. But this will be hard to implement, so we decided to do it when the
   time comes.

frontend/coprs_frontend/coprs/config.py

@@ -201,6 +201,11 @@ class Config(object):
     ROLLING_CHROOTS_INACTIVITY_WARNING = 180
     ROLLING_CHROOTS_INACTIVITY_REMOVAL = 180
 
+    # If build results for (some) projects are stored in Pulp, what is the
+    # shared part of the URL for all repositories, e.g.
+    # https://pulp.stage.devshift.net/api/pulp-content/copr
+    PULP_CONTENT_URL = None
+
 
 class ProductionConfig(Config):
     DEBUG = False

frontend/coprs_frontend/coprs/templates/coprs/copr_dir.repo

@@ -1,11 +1,16 @@
 [{{ repo_id }}]
 name={{ name }}
 {{- " (" + arch + ")" if arch }}
+{% if not pulp %}
 baseurl={{ url | fix_url_https_backend }}
-type=rpm-md
-skip_if_unavailable=True
 gpgcheck={{ config.REPO_GPGCHECK | default("1")}}
 gpgkey={{ pubkey_url | fix_url_https_backend  }}
+{% else %}
+baseurl={{ url }}
+gpgcheck=0
+{% endif %}
+type=rpm-md
+skip_if_unavailable=True
 repo_gpgcheck=0
 {% if cost %}
 cost={{ cost }}

frontend/coprs_frontend/coprs/views/coprs_ns/coprs_general.py

@@ -21,6 +21,7 @@
 from pygments.lexers import get_lexer_by_name
 from pygments.formatters import HtmlFormatter
 
+from copr_common.enums import StorageEnum
 from coprs import app
 from coprs import cache
 from coprs import db
@@ -861,14 +862,20 @@ def render_repo_template(copr_dir, mock_chroot, arch=None, cost=None, runtime_de
         copr_dir.copr, copr_dir.name, multilib=arch,
         dep_idx=runtime_dep, dependent=dependent)
 
-    url = os.path.join(copr_dir.repo_url, '') # adds trailing slash
-    repo_url = generate_repo_url(mock_chroot, url, arch)
-    pubkey_url = urljoin(url, "pubkey.gpg")
+    pulp = copr_dir.copr.storage == StorageEnum.pulp
+    if pulp:
+        url = "/".join([app.config["PULP_CONTENT_URL"], copr_dir.full_name])
+        pubkey_url = None
+    else:
+        url = os.path.join(copr_dir.repo_url, '') # adds trailing slash
+        pubkey_url = urljoin(url, "pubkey.gpg")
 
+    repo_url = generate_repo_url(mock_chroot, url, arch)
     return flask.render_template("coprs/copr_dir.repo", copr_dir=copr_dir,
                                  url=repo_url, pubkey_url=pubkey_url,
                                  repo_id=repo_id, arch=arch, cost=cost,
-                                 name=name, repo_priority=copr_dir.copr.repo_priority)
+                                 name=name, pulp=pulp,
+                                 repo_priority=copr_dir.copr.repo_priority)
 
 
 def _render_external_repo_template(dep, copr_dir, mock_chroot, dep_idx):