feat: add cache to hydrator

.schema/config.schema.json

@@ -843,6 +843,21 @@
               "$ref": "#/definitions/retry"
             }
           }
+        },
+        "cache": {
+          "additionalProperties": false,
+          "required": [
+            "ttl"
+          ],
+          "type": "object",
+          "properties": {
+            "ttl": {
+              "type": "string",
+              "pattern": "^[0-9]+(ns|us|ms|s|m|h)$",
+              "title": "Cache Time to Live",
+              "description": "How long to cache hydrate calls"
+            }
+          }
         }
       },
       "required": [

docs/docs/pipeline/mutator.md

@@ -491,6 +491,7 @@ in the `header` field will be added to the final request headers.
 - `api.url` (string - required) - The API URL.
 - `api.auth.basic.*` (optional) - Enables HTTP Basic Authorization.
 - `api.auth.retry.*` (optional) - Configures the retry logic.
+- `cache.ttl` (optional) - Configures how long to cache hydrate requests
 
 ```yaml
 # Global configuration file oathkeeper.yml
@@ -508,6 +509,8 @@ mutators:
         retry:
           give_up_after: 2s
           max_delay: 100ms
+      cache:
+        ttl: 60s
 ```
 
 ```yaml
@@ -527,6 +530,8 @@ mutators:
         retry:
           give_up_after: 2s
           max_delay: 100ms
+      cache:
+        ttl: 60s
 ```
 
 ### Access Rule Example

go.mod

@@ -1,6 +1,7 @@
 module github.com/ory/oathkeeper
 
 require (
+	github.com/Azure/go-autorest/logger v0.1.0 // indirect
 	github.com/Masterminds/goutils v1.1.0 // indirect
 	github.com/Masterminds/sprig v2.20.0+incompatible
 	github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a

go.sum

@@ -11,6 +11,9 @@ cloud.google.com/go/datastore v1.0.0/go.mod h1:LXYbyblFSglQ5pkeyhO+Qmw7ukd3C+pD7
 cloud.google.com/go/pubsub v1.0.1/go.mod h1:R0Gpsv3s54REJCy4fxDixWD93lHJMoZTyQ2kNxGRt3I=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 h1:w+iIsaOQNcT7OZ575w+acHgRric5iCyQh+xv+KJ4HB8=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78/go.mod h1:LmzpDX56iTiv29bbRTIsUNlaFfuhWRQBWjQdVyAevI8=
+github.com/Azure/go-autorest v14.0.1+incompatible h1:YhojO9jolWIvvTW7ORhz2ZSNF6Q1TbLqUunKd3jrtyw=
+github.com/Azure/go-autorest/logger v0.1.0 h1:ruG4BSDXONFRrZZJ2GUXDiUyVpayPmb1GnWeHDdaNKY=
+github.com/Azure/go-autorest/logger v0.1.0/go.mod h1:oExouG+K6PryycPJfVSxi/koC6LSNgds39diKLz7Vrc=
 github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
@@ -897,6 +900,7 @@ github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXf
 github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H4=
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/subosito/gotenv v1.1.1/go.mod h1:N0PQaV/YGNqwC0u51sEeR/aUtSLEXKX9iv69rRypqCw=
 github.com/subosito/gotenv v1.2.0 h1:Slr1R9HxAlEKefgq5jn9U+DnETlIUa6HfgEzj0g5d7s=
@@ -1197,6 +1201,7 @@ google.golang.org/appengine v1.5.0/go.mod h1:xpcJRLb0r/rnEns0DIKYYv+WjYCduHsrkT7
 google.golang.org/appengine v1.6.1/go.mod h1:i06prIuMbXzDqacNJfV5OdTW448YApPu5ww/cMBSeb0=
 google.golang.org/appengine v1.6.2 h1:j8RI1yW0SkI+paT6uGwMlrMI/6zwYA6/CFil8rxOzGI=
 google.golang.org/appengine v1.6.2/go.mod h1:i06prIuMbXzDqacNJfV5OdTW448YApPu5ww/cMBSeb0=
+google.golang.org/appengine v1.6.5 h1:tycE03LOZYQNhDpS27tcQdAzLCVMaj7QT2SXxebnpCM=
 google.golang.org/appengine v1.6.5/go.mod h1:8WjMMxjGQR8xUklV/ARdw2HLXBOI7O7uCIDZVag1xfc=
 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/genproto v0.0.0-20190307195333-5fe7a883aa19/go.mod h1:VzzqZJRnGkLBvHegQrXjBqPurQTc5/KpmUdxsrq26oE=

pipeline/mutate/mutator_hydrator.go

@@ -23,10 +23,13 @@ package mutate
 import (
 	"bytes"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"net/url"
 	"time"
 
+	"github.com/dgraph-io/ristretto"
+
 	"github.com/ory/oathkeeper/pipeline/authn"
 	"github.com/ory/oathkeeper/x"
 
@@ -55,6 +58,9 @@ type MutatorHydrator struct {
 	c      configuration.Provider
 	client *http.Client
 	d      mutatorHydratorDependencies
+
+	hydrateCache *ristretto.Cache
+	cacheTTL     *time.Duration
 }
 
 type BasicAuth struct {
@@ -77,22 +83,67 @@ type externalAPIConfig struct {
 	Retry *retryConfig `json:"retry"`
 }
 
+type cacheConfig struct {
+	TTL string `json:"ttl"`
+}
+
 type MutatorHydratorConfig struct {
-	Api externalAPIConfig `json:"api"`
+	Api   externalAPIConfig `json:"api"`
+	Cache cacheConfig       `json:"cache"`
 }
 
 type mutatorHydratorDependencies interface {
 	x.RegistryLogger
 }
 
 func NewMutatorHydrator(c configuration.Provider, d mutatorHydratorDependencies) *MutatorHydrator {
-	return &MutatorHydrator{c: c, d: d, client: httpx.NewResilientClientLatencyToleranceSmall(nil)}
+	cache, _ := ristretto.NewCache(&ristretto.Config{
+		// This will hold about 1000 unique mutation responses.
+		NumCounters: 10000,
+		// Allocate a max of 32MB
+		MaxCost: 1 << 25,
+		// This is a best-practice value.
+		BufferItems: 64,
+	})
+	return &MutatorHydrator{c: c, d: d, client: httpx.NewResilientClientLatencyToleranceSmall(nil), hydrateCache: cache}
 }
 
 func (a *MutatorHydrator) GetID() string {
 	return "hydrator"
 }
 
+func (a *MutatorHydrator) cacheKey(config *MutatorHydratorConfig, session *authn.AuthenticationSession) string {
+	return fmt.Sprintf("%s|%s", config.Api.URL, session.Subject)
+}
+
+func (a *MutatorHydrator) hydrateFromCache(config *MutatorHydratorConfig, session *authn.AuthenticationSession) (*authn.AuthenticationSession, bool) {
+	if a.cacheTTL == nil {
+		return nil, false
+	}
+
+	key := a.cacheKey(config, session)
+
+	item, found := a.hydrateCache.Get(key)
+	if !found {
+		return nil, false
+	}
+
+	container := item.(*authn.AuthenticationSession)
+	return container, true
+}
+
+func (a *MutatorHydrator) hydrateToCache(config *MutatorHydratorConfig, session *authn.AuthenticationSession) {
+	if a.cacheTTL == nil {
+		return
+	}
+
+	key := a.cacheKey(config, session)
+	cached := a.hydrateCache.SetWithTTL(key, session, 0, *a.cacheTTL)
+	if !cached {
+		a.d.Logger().Warn("Item not added to cache")
+	}
+}
+
 func (a *MutatorHydrator) Mutate(r *http.Request, session *authn.AuthenticationSession, config json.RawMessage, _ pipeline.Rule) error {
 	cfg, err := a.Config(config)
 	if err != nil {
@@ -104,6 +155,11 @@ func (a *MutatorHydrator) Mutate(r *http.Request, session *authn.AuthenticationS
 		return errors.WithStack(err)
 	}
 
+	if cacheSession, ok := a.hydrateFromCache(cfg, session); ok {
+		*session = *cacheSession
+		return nil
+	}
+
 	if cfg.Api.URL == "" {
 		return errors.New(ErrMissingAPIURL)
 	} else if _, err := url.ParseRequestURI(cfg.Api.URL); err != nil {
@@ -174,6 +230,8 @@ func (a *MutatorHydrator) Mutate(r *http.Request, session *authn.AuthenticationS
 	}
 	*session = sessionFromUpstream
 
+	a.hydrateToCache(cfg, session)
+
 	return nil
 }
 
@@ -192,5 +250,14 @@ func (a *MutatorHydrator) Config(config json.RawMessage) (*MutatorHydratorConfig
 		return nil, NewErrMutatorMisconfigured(a, err)
 	}
 
+	if c.Cache.TTL != "" {
+		cacheTTL, err := time.ParseDuration(c.Cache.TTL)
+		if err != nil {
+			a.d.Logger().WithError(err).Error("Unable to parse cache ttl in the Hydrator Mutator.")
+			return nil, NewErrMutatorMisconfigured(a, err)
+		}
+		a.cacheTTL = &cacheTTL
+	}
+
 	return &c, nil
 }