Milo flex raw log viewer endpoint

milo/appengine/common/middleware.go

Index: milo/appengine/common/middleware.go
diff --git a/milo/appengine/common/middleware.go b/milo/appengine/common/middleware.go
index daef78d87690eb9cab334f9cff9f673c2a3beeb2..c5fb5e853e77f399db2a90982e0d29e5e5ba34c0 100644
--- a/milo/appengine/common/middleware.go
+++ b/milo/appengine/common/middleware.go
@@ -8,14 +8,25 @@ import (
 	"net/http"
 	"strings"
 
+	"cloud.google.com/go/compute/metadata"
+	"cloud.google.com/go/datastore"
+
 	"golang.org/x/net/context"
+	"golang.org/x/oauth2"
+	"golang.org/x/oauth2/google"
 
+	"github.com/luci/gae/impl/cloud"
+	"github.com/luci/gae/impl/memory"
 	"github.com/luci/gae/service/info"
 	"github.com/luci/luci-go/appengine/gaeauth/server"
+	"github.com/luci/luci-go/appengine/gaeauth/server/gaesigner"
 	"github.com/luci/luci-go/appengine/gaemiddleware"
+	"github.com/luci/luci-go/appengine/gaesecrets"
 	"github.com/luci/luci-go/common/clock"
+	"github.com/luci/luci-go/common/logging/gologger"
 	"github.com/luci/luci-go/server/analytics"
 	"github.com/luci/luci-go/server/auth"
+	"github.com/luci/luci-go/server/auth/authdb"
 	"github.com/luci/luci-go/server/auth/identity"
 	"github.com/luci/luci-go/server/router"
 	"github.com/luci/luci-go/server/templates"
@@ -54,14 +65,76 @@ func GetTemplateBundle() *templates.Bundle {
 	}
 }
 
-// Base returns the basic LUCI appengine middlewares.
-func Base() router.MiddlewareChain {
-	methods := auth.Authenticator{
+// authMethods returns the set of authentication methods used for Milo.
+func authMethods() auth.Authenticator {
+	return auth.Authenticator{
 		&server.OAuth2Method{Scopes: []string{server.EmailScope}},
 		server.CookieAuth,
 		&server.InboundAppIDAuthMethod{},
 	}
-	m := gaemiddleware.BaseProd().Extend(auth.Use(methods), auth.Authenticate)
+}
+
+// Flex returns the basic middleware for use on appengine flex.  Flex does not
+// allow the use of appengine APIs.
+func FlexBase() router.MiddlewareChain {
+	// Get the name of this project from the metadata server, since we're on GCE.
+	project, err := metadata.Get("project/project-id")
+	if err != nil {
+		panic(err)
+	}
+	// Use the standard Go logger.
+	// TODO(hinoka): Use the cloud logger, somehow.
+	logger := func(c *router.Context, next router.Handler) {
+		c.Context = gologger.StdConfig.Use(c.Context)
+		next(c)
+	}
+	// The base set of services uses memory implementations.
+	memory := func(c *router.Context, next router.Handler) {
+		c.Context = memory.UseWithAppID(c.Context, project)
+		next(c)
+	}
+	// Use the cloud datastore client.
+	ds := func(c *router.Context, next router.Handler) {
+		client, err := datastore.NewClient(c.Context, project)
+		if err != nil {
+			panic(err)
+		}
+		c.Context = cloud.UseDatastore(c.Context, client)
+		next(c)
+	}
+	// Secret store, used for decryping OID tokens, which is needed for cookieauth.
+	secrets := func(c *router.Context, next router.Handler) {
+		c.Context = gaesecrets.Use(c.Context, nil)
+		next(c)
+	}
+	// Swap out the default auth configs with one that uses a in-memory cache, since
+	// we can't use memcache.
+	authConfig := func(c *router.Context, next router.Handler) {
+		mustToken := func(c context.Context, scopes []string) (*oauth2.Token, error) {
+			// Ignore context and scope since its not needed.
+			return google.ComputeTokenSource("").Token()
+		}
+		config := auth.Config{
+			DBProvider:          authdb.NewDBCache(server.GetAuthDB),
+			Signer:              gaesigner.Signer{},
+			AccessTokenProvider: mustToken,
+			AnonymousTransport: func(c context.Context) http.RoundTripper {
+				return http.DefaultTransport
+			},
+			Cache:     auth.MemoryCache(10),
+			IsDevMode: false,
+		}
+		c.Context = auth.SetConfig(c.Context, config)
+		next(c)
+	}
+	// Now chain it all together!
+	return router.NewMiddlewareChain(
+		logger, memory, ds, secrets, auth.Use(authMethods()), authConfig, auth.Authenticate)
+}
+
+// Base returns the basic LUCI appengine middlewares.
+func Base() router.MiddlewareChain {
+	m := gaemiddleware.BaseProd().Extend(auth.Use(authMethods()), auth.Authenticate)
 	m = m.Extend(withRequestMiddleware)
 	m = m.Extend(templates.WithTemplates(GetTemplateBundle()))
 	return m