3 files changed, 9 insertions, 7 deletions

diff --git a/README.md b/README.md
index 1898572..2e2cc24 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ Arguments:
 - `-uri=<uri>`: The default address to open in the proxy (default: "floodgap.com")
 - `-robots-file=<file>`: robots.txt file to serve to protect Gopher sites from web crawlers (default: "robots.txt")
 - `-robots-debug=<true|false>`: Print output about clients ignoring robots.txt (this includes regular browsers) (default: false)
+- `-vips-concurrency=<n>: Concurrency level of libvips (i.e. number of worker threads)`
 
 
 ## Development
diff --git a/cmd/gopherproxy/main.go b/cmd/gopherproxy/main.go
index e9dea18..e699d14 100644
--- a/cmd/gopherproxy/main.go
+++ b/cmd/gopherproxy/main.go
@@ -10,15 +10,16 @@ import (
 var (
         // TODO: Allow config file and environment vars
         //       (opt -> env -> config -> default)
-        bind        = flag.String("bind", "0.0.0.0:8000", "[int]:port to bind to")
-        robotsfile  = flag.String("robots-file", "robots.txt", "robots.txt file")
-        robotsdebug = flag.Bool("robots-debug", false, "print output about ignored robots.txt")
-        uri         = flag.String("uri", "floodgap.com", "<host>:[port] to proxy to")
+        bind            = flag.String("bind", "0.0.0.0:8000", "[int]:port to bind to")
+        robotsfile      = flag.String("robots-file", "robots.txt", "robots.txt file")
+        robotsdebug     = flag.Bool("robots-debug", false, "print output about ignored robots.txt")
+        uri             = flag.String("uri", "floodgap.com", "<host>:[port] to proxy to")
+        vipsconcurrency = flag.Int("vips-concurrency", 1, "Concurrency level of libvips")
 )
 
 func main() {
         flag.Parse()
 
         // Use a config struct
-        log.Fatal(gopherproxy.ListenAndServe(*bind, *robotsfile, *robotsdebug, *uri))
+        log.Fatal(gopherproxy.ListenAndServe(*bind, *robotsfile, *robotsdebug, *vipsconcurrency, *uri))
 }
diff --git a/gopherproxy.go b/gopherproxy.go
index 0ecfa14..0134f88 100644
--- a/gopherproxy.go
+++ b/gopherproxy.go
@@ -242,7 +242,7 @@ func FontHandler(woff2 bool, fontdata []byte) http.HandlerFunc {
 // specified by the request. The robots argument is a pointer to
 // a robotstxt.RobotsData struct for testing user agents against
 // a configurable robots.txt file.
-func ListenAndServe(bind, robotsfile string, robotsdebug bool, uri string) error {
+func ListenAndServe(bind, robotsfile string, robotsdebug bool, vipsconcurrency int, uri string) error {
         var (
                 tpl        *template.Template
                 robotsdata *robotstxt.RobotsData
@@ -329,7 +329,7 @@ func ListenAndServe(bind, robotsfile string, robotsdebug bool, uri string) error
         }
 
         vips.Startup(&vips.Config{
-                ConcurrencyLevel: 0,
+                ConcurrencyLevel: vipsconcurrency,
         })
 
         http.HandleFunc("/", GopherHandler(tpl, robotsdata, AssetHashList{stylehash, jshash, fontwhash, fontw2hash}, robotsdebug, uri))