Make HTTP middleware easier to use

appengine/gaemiddleware/context.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package gaemiddleware
 
 import (
         "net/http"
 
+        "golang.org/x/net/context"
         "google.golang.org/appengine"
 
-        "github.com/julienschmidt/httprouter"
-        "golang.org/x/net/context"
-
         "github.com/luci/gae/filter/dscache"
         "github.com/luci/gae/impl/prod"
         "github.com/luci/luci-go/appengine/gaeauth/client"
         "github.com/luci/luci-go/appengine/gaeauth/server"
         "github.com/luci/luci-go/appengine/gaeauth/server/gaesigner"
         "github.com/luci/luci-go/appengine/gaesecrets"
         "github.com/luci/luci-go/appengine/gaesettings"
         "github.com/luci/luci-go/appengine/tsmon"
         "github.com/luci/luci-go/common/cacheContext"
         "github.com/luci/luci-go/common/logging"
         "github.com/luci/luci-go/server/auth"
         "github.com/luci/luci-go/server/middleware"
         "github.com/luci/luci-go/server/proccache"
+        "github.com/luci/luci-go/server/router"
         "github.com/luci/luci-go/server/settings"
 )
 
 var (
         // globalProcessCache holds state cached between requests.
         globalProcessCache = &proccache.Cache{}
 
         // globalSettings holds global app settings lazily updated from the datastore.
         globalSettings = settings.New(gaesettings.Storage{})
 
@@ skipping 29 matching lines @@
 
         // The rest of the service may use applied configuration.
         c = proccache.Use(c, globalProcessCache)
         c = client.UseAnonymousTransport(c)
         c = gaesecrets.Use(c, nil)
         c = gaesigner.Use(c)
         c = auth.UseDB(c, globalAuthDBCache)
         return cacheContext.Wrap(c)
 }
 
-// BaseProd adapts a middleware-style handler to a httprouter.Handle.
-//
-// It installs services using WithProd, installs a panic catcher if this
-// is not a devserver, and injects the monitoring middleware.
-func BaseProd(h middleware.Handler) httprouter.Handle {
-        h = globalTsMonState.Middleware(h)
-        if !appengine.IsDevAppServer() {
-                h = middleware.WithPanicCatcher(h)
+// ProdServices is a middleware that installs the set of standard production
+// AppEngine services by calling WithProd.
+func ProdServices(c *router.Context, next router.Handler) {
+        c.Context = WithProd(c.Context, c.Request)
+        next(c)
+}
+
+// BaseProd returns a list of middleware: WithProd middleware, a panic catcher if this
+// is not a devserver, and the monitoring middleware.
+func BaseProd() router.MiddlewareChain {
+        if appengine.IsDevAppServer() {
+                return router.MiddlewareChain{ProdServices, globalTsMonState.Middleware}
         }
-        return func(rw http.ResponseWriter, r *http.Request, p httprouter.Params) {
-                h(WithProd(context.Background(), r), rw, r, p)
+        return router.MiddlewareChain{
+                ProdServices, middleware.WithPanicCatcher, globalTsMonState.Middleware,
         }
 }