Improve logging

- Actually log useful information at their respective log level.
- Add logs in hot-paths to be able to deep-dive and debug specific
requests (see server/handler.go)
- Remove zerologger and instead use custom logger that doesn't log
JSON (directly inspired by https://codeberg.org/Codeberg/moderation/pulls/7).
- Add more information to existing fields(e.g. the host that the user is
visiting, this was noted by @fnetX).

server/upstream/upstream.go

@@ -8,12 +8,12 @@ import (
 	"strings"
 	"time"
 
-	"github.com/rs/zerolog/log"
 	"github.com/valyala/fasthttp"
 
 	"codeberg.org/codeberg/pages/html"
 	"codeberg.org/codeberg/pages/server/cache"
 	"codeberg.org/codeberg/pages/server/gitea"
+	"codeberg.org/codeberg/pages/server/log"
 )
 
 // upstreamIndexPages lists pages that may be considered as index pages for directories.
@@ -33,7 +33,10 @@ type Options struct {
 	TargetBranch,
 	TargetPath,
 
-	DefaultMimeType string
+	// Used for debugging purposes.
+	Host string
+
+	DefaultMimeType    string
 	ForbiddenMimeTypes map[string]bool
 	TryIndexPages      bool
 	BranchTimestamp    time.Time
@@ -44,7 +47,7 @@ type Options struct {
 
 // Upstream requests a file from the Gitea API at GiteaRoot and writes it to the request context.
 func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client, branchTimestampCache, fileResponseCache cache.SetGetKey) (final bool) {
-	log := log.With().Strs("upstream", []string{o.TargetOwner, o.TargetRepo, o.TargetBranch, o.TargetPath}).Logger()
+	logInfo := fmt.Sprintf("[owner=%q, repo=%q, branch=%q, path=%q, host=%q]", o.TargetOwner, o.TargetRepo, o.TargetBranch, o.TargetPath, o.Host)
 
 	// Check if the branch exists and when it was modified
 	if o.BranchTimestamp.IsZero() {
@@ -70,7 +73,8 @@ func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client,
 			return true
 		}
 	}
-	log.Debug().Msg("preparations")
+
+	log.Debug("Preparing %s", logInfo)
 
 	// Make a GET request to the upstream URL
 	uri := o.generateUri()
@@ -82,7 +86,7 @@ func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client,
 	} else {
 		res, err = giteaClient.ServeRawContent(uri)
 	}
-	log.Debug().Msg("acquisition")
+	log.Debug("Aquisting %s", logInfo)
 
 	// Handle errors
 	if (err != nil && errors.Is(err, gitea.ErrorNotFound)) || (res == nil && !cachedResponse.Exists) {
@@ -136,7 +140,7 @@ func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client,
 		return false
 	}
 	if res != nil && (err != nil || res.StatusCode() != fasthttp.StatusOK) {
-		fmt.Printf("Couldn't fetch contents from \"%s\": %s (status code %d)\n", uri, err, res.StatusCode())
+		log.Warn("Couldn't fetch contents from %q: %v (status code %d)", uri, err, res.StatusCode())
 		html.ReturnErrorPage(ctx, fasthttp.StatusInternalServerError)
 		return true
 	}
@@ -155,7 +159,7 @@ func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client,
 		ctx.Redirect(o.redirectIfExists, fasthttp.StatusTemporaryRedirect)
 		return true
 	}
-	log.Debug().Msg("error handling")
+	log.Debug("Handling error %s", logInfo)
 
 	// Set the MIME type
 	mimeType := o.getMimeTypeByExtension()
@@ -175,7 +179,7 @@ func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client,
 	}
 	ctx.Response.Header.SetLastModified(o.BranchTimestamp)
 
-	log.Debug().Msg("response preparations")
+	log.Debug("Prepare response %s", logInfo)
 
 	// Write the response body to the original request
 	var cacheBodyWriter bytes.Buffer
@@ -197,7 +201,7 @@ func (o *Options) Upstream(ctx *fasthttp.RequestCtx, giteaClient *gitea.Client,
 		html.ReturnErrorPage(ctx, fasthttp.StatusInternalServerError)
 		return true
 	}
-	log.Debug().Msg("response")
+	log.Debug("Sending response %s", logInfo)
 
 	if res != nil && res.Header.ContentLength() <= fileCacheSizeLimit && ctx.Err() == nil {
 		cachedResponse.Exists = true