log: Drop `Debugf()` function from `Logger` interface

Next to `Debug()` and related functions our `Logger` interface also
provides `Debugf()` and related functions that takes a formatting string
as well as a set of arguments for it. There are multiple reasons though
why we don't want to expose these functions:

    - They do not exist in the `slog` package, which thus causes our own
      internal interface to diverge from our desired target solution.

    - It is discouraged to put variable data into the message itself.
      Instead, callsites are encouraged to add any variable data as
      structured log data.

    - It often gets abused in contexts where it's not required at all to
      call the formatting variant as all we pass in is a static string.

    - We have a pending addition of logging functions that also take a
      context parameter as input. The formatting family would cause us
      to require four more functions that take such a context as input.

Let's remove `Debugf()` in favor of `Debug()`. Most of the existing
callsites are converted to instead use structured logging data.

1 files changed, 1 insertions, 1 deletions

diff --git a/internal/praefect/coordinator.go b/internal/praefect/coordinator.go
index a95bab79b..e2a8875e4 100644
--- a/internal/praefect/coordinator.go
+++ b/internal/praefect/coordinator.go
@@ -665,7 +665,7 @@ func streamParametersContext(ctx context.Context) context.Context {
 func (c *Coordinator) StreamDirector(ctx context.Context, fullMethodName string, peeker proxy.StreamPeeker) (*proxy.StreamParameters, error) {
 	// For phase 1, we need to route messages based on the storage location
 	// to the appropriate Gitaly node.
-	log.FromContext(ctx).Debugf("Stream director received method %s", fullMethodName)
+	log.FromContext(ctx).WithField("method", fullMethodName).Debug("Stream director received method")
 
 	mi, err := c.registry.LookupMethod(fullMethodName)
 	if err != nil {