From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 5 Aug 2025 12:40:18 +0000 (+1000)
Subject: Expose TORRENT_WEBSEED_REQUEST_CHUNK_SIZE
X-Git-Tag: v1.59.0~2^2~56
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=64a11e2464d300efa5eebed9e4f9ee407a49d016;p=btrtrc.git

Expose TORRENT_WEBSEED_REQUEST_CHUNK_SIZE
---

diff --git a/env.go b/env.go
index c8759d6e..996e1a8f 100644
--- a/env.go
+++ b/env.go
@@ -8,12 +8,20 @@ import (
 	"golang.org/x/exp/constraints"
 )
 
-func initIntFromEnv[T constraints.Integer](key string, defaultValue T, bitSize int) T {
+func initIntFromEnv[T constraints.Signed](key string, defaultValue T, bitSize int) T {
+	return strconvFromEnv(key, defaultValue, bitSize, strconv.ParseInt)
+}
+
+func initUIntFromEnv[T constraints.Unsigned](key string, defaultValue T, bitSize int) T {
+	return strconvFromEnv(key, defaultValue, bitSize, strconv.ParseUint)
+}
+
+func strconvFromEnv[T, U constraints.Integer](key string, defaultValue T, bitSize int, conv func(s string, base, bitSize int) (U, error)) T {
 	s := os.Getenv(key)
 	if s == "" {
 		return defaultValue
 	}
-	i64, err := strconv.ParseInt(s, 10, bitSize)
+	i64, err := conv(s, 10, bitSize)
 	panicif.Err(err)
 	return T(i64)
 }
diff --git a/webseed-requesting.go b/webseed-requesting.go
index d41d909c..d290d525 100644
--- a/webseed-requesting.go
+++ b/webseed-requesting.go
@@ -233,8 +233,9 @@ func (t *Torrent) getWebseedRequestEnd(begin RequestIndex, debugLogger *slog.Log
 	return end
 }
 
-// Cloudflare caches up to 512 MB responses by default. This is also an alignment.
-var webseedRequestChunkSize uint64 = 256 << 20
+// Cloudflare caches up to 512 MB responses by default. This is also an alignment. Making this
+// smaller will allow requests to complete a smaller set of files faster.
+var webseedRequestChunkSize = initUIntFromEnv[uint64]("TORRENT_WEBSEED_REQUEST_CHUNK_SIZE", 64<<20, 64)
 
 func (t *Torrent) endRequestForAlignedWebseedResponse(start RequestIndex) RequestIndex {
 	end := min(t.maxEndRequest(), nextMultiple(start, t.chunksPerAlignedWebseedResponse()))