add a cache server entry in pacman configuration snippet

The server error limit was introduced in pacman 6.0.0, which caused some
trouble with pacredir: Returning 404 (not found) is common case and no
fatal error.

Add a cache server with different address to make sure to request files
from pacredir in case the address above was caught by pacman's server
error limit.

2 files changed, 8 insertions, 60 deletions

diff --git a/README.md b/README.md
index dd64de7..11cbeb2 100644
--- a/README.md
+++ b/README.md
@@ -69,66 +69,6 @@ make sure you really do have the latest files run `pacman -Syu` *twice*.
 To get a better idea what happens in the background have a look at
 [the request flow chart](FLOW.md).
 
-Current caveat
---------------
-
-With its latest release `pacman` now supports a *server error limit*: Three
-download errors from a server results in the server being skipped for the
-remainder of this transaction.
-However `pacredir` sends a "*404 - not found*" response if the file is not
-available in local network - and is skipped after just three misses.
-
-This new feature is not configurable at runtime, so rebuilding `pacman` with
-one of the following patches is the way to make things work with `pacredir`.
-
-### Disable server error limit
-
-This is the simplest workaround - just disable the server error limit.
-
-    --- a/lib/libalpm/dload.c
-    +++ b/lib/libalpm/dload.c
-    @@ -60,7 +60,7 @@ static int curl_gethost(const char *url, char *buffer, size_t buf_len);
-     
-     /* number of "soft" errors required to blacklist a server, set to 0 to disable
-      * server blacklisting */
-    -const unsigned int server_error_limit = 3;
-    +const unsigned int server_error_limit = 0;
-     
-     struct server_error_count {
-     	char server[HOSTNAME_SIZE];
-
-We can agree this is not to be desired - in general the feature is reasonable.
-
-### Support http header to indicate a soft failure
-
-This solution is simple, yet powerful:
-[Support http header 'Cache-Control: no-cache' for soft failure](patches/0001-support-http-header-Cache-Control-no-cache-for-soft-failure.patch)
-
-By setting the HTTP header `Cache-Control: no-cache` when returning with
-the status code `404` (not found) the server can indicate that this is a
-soft failure. No error message is shown, and server's error count is
-not increased.
-
-Sadly upstream denied, again. 😢
-
-Anyway, pushed this as merge request to Gitlab:
-[support http header 'Cache-Control: no-cache' for soft failure](https://gitlab.archlinux.org/pacman/pacman/-/merge_requests/76)
-
-### Implement CacheServer
-
-A more complex solution that breaks current API is:
-[Implement CacheServer](patches/0001-implement-CacheServer.patch)
-
-This implements a new configuration option `CacheServer`. Adding a cache
-server makes it ignore the server error limit.
-
-Handling for soft failures is demanded in a long standing upstream bug, and
-the given patch could solve it:
-[FS#23407 - Allow soft failures on Server URLs](https://bugs.archlinux.org/task/23407)
-
-Pushed this as merge request to Gitlab:
-[implement CacheServer](https://gitlab.archlinux.org/pacman/pacman/-/merge_requests/74)
-
 Security
 --------
 
diff --git a/pacman/pacredir b/pacman/pacredir
index 0a1e1fc..9df0184 100644
--- a/pacman/pacredir
+++ b/pacman/pacredir
@@ -1,2 +1,10 @@
 # Make sure local service pacredir is running!
+
+# This is a regular server, so pacredir receives requests for database
+# files, but it is also accounted for server error limit.
 Server = http://127.0.0.1:7077/
+
+# Add a cache server with different address to make sure pacman requests
+# package files from pacredir in case the address above was caught by
+# pacman's server error limit.
+CacheServer = http://127.0.0.2:7077/