Add SQL query cacheing

config/dev.yml

@@ -2,6 +2,8 @@ app_name: "Super Graph Development"
 host_port: 0.0.0.0:8080
 web_ui: true
 debug_level: 1
+
+# enabling tracing also disables query caching
 enable_tracing: true
 
 # Throw a 401 on auth failure for queries that need auth

config/prod.yml

@@ -2,6 +2,8 @@ app_name: "Super Graph Production"
 host_port: 0.0.0.0:8080
 web_ui: false
 debug_level: 0
+
+# disabled tracing enables query caching
 enable_tracing: false
 
 # Throw a 401 on auth failure for queries that need auth

corpus/5

@@ -1,5 +1,5 @@
 query {
-  product(id: 15) {
+  product(id: $PRODUCT_ID, where: { price: { eq: $PRODUCT_PRICE } }) {
     id
     name
   }

corpus/6

@@ -1,21 +1,6 @@
 query {
-  products(
+  product(id: 15) {
-    # returns only 30 items
-    limit: 30,
-
-    # starts from item 10, commented out for now
-    # offset: 10,
-
-    # orders the response items by highest price
-    order_by: { price: desc },
-
-    # no duplicate prices returned
-    distinct: [ price ]
-    
-    # only items with an id >= 30 and < 30 are returned
-    where: { id: { and: { greater_or_equals: 20, lt: 28 } } }) {
     id
     name
-    price
   }
 }

docs/guide.md

@@ -240,6 +240,29 @@ query {
 }
 ```
 
+### Using variables
+
+Variables and their values can be passed along side the GraphQL query. Using variables makes for better client side code as well as improved server side
+caching. The build-in web ui also hass support for variables. Not having to manupilate your GraphQL query string to insert values into it makes for cleaner
+and better client side code.
+
+```javascript
+// define the request object keeping the query and the variables seperate
+var req = { 
+  query: '{ product(id: $product_id) { name } }' ,
+  variables: { "product_id": 5 }
+}
+
+// use the fetch api to make the query
+fetch('http://localhost:8080/api/v1/graphql', {
+  method: 'POST',
+  headers: { 'Content-Type': 'application/json' },
+  body: JSON.stringify(req),
+})
+.then(res => res.json())
+.then(res => console.log(res.data));
+```
+
 ### Full text search
 
 Every app these days needs search. Enought his often means reaching for something heavy like Solr. While this will work why add complexity to your infrastructure when Postgres has really great
@@ -412,11 +435,13 @@ Configuration files can either be in YAML or JSON their names are derived from t
 We're tried to ensure that the config file is self documenting and easy to work with.
 
 ```yaml
-title: Super Graph Development
+app_name: "Super Graph Development"
 host_port: 0.0.0.0:8080
 web_ui: true
 debug_level: 1
-enable_tracing: false
+
+# enabling tracing also disables query caching
+enable_tracing: true
 
 # Throw a 401 on auth failure for queries that need auth
 # valid values: always, per_query, never

go.mod

@@ -3,6 +3,7 @@ module github.com/dosco/super-graph
 require (
 	github.com/Masterminds/semver v1.4.2
 	github.com/adjust/gorails v0.0.0-20171013043634-2786ed0c03d3
+	github.com/allegro/bigcache v1.2.0
 	github.com/bradfitz/gomemcache v0.0.0-20180710155616-bc664df96737
 	github.com/dgrijalva/jwt-go v3.2.0+incompatible
 	github.com/garyburd/redigo v1.6.0

go.sum

@@ -4,6 +4,8 @@ github.com/Masterminds/semver v1.4.2 h1:WBLTQ37jOCzSLtXNdoo8bNM8876KhNqOKvrlGITg
 github.com/Masterminds/semver v1.4.2/go.mod h1:MB6lktGJrhw8PrUyiEoblNEGEQ+RzHPF078ddwwvV3Y=
 github.com/adjust/gorails v0.0.0-20171013043634-2786ed0c03d3 h1:+qz9Ga6l6lKw6fgvk5RMV5HQznSLvI8Zxajwdj4FhFg=
 github.com/adjust/gorails v0.0.0-20171013043634-2786ed0c03d3/go.mod h1:FlkD11RtgMTYjVuBnb7cxoHmQGqvPpCsr2atC88nl/M=
+github.com/allegro/bigcache v1.2.0 h1:qDaE0QoF29wKBb3+pXFrJFy1ihe5OT9OiXhg1t85SxM=
+github.com/allegro/bigcache v1.2.0/go.mod h1:Cb/ax3seSYIx7SuZdm2G2xzfwmv3TPSk2ucNfQESPXM=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
 github.com/bradfitz/gomemcache v0.0.0-20180710155616-bc664df96737 h1:rRISKWyXfVxvoa702s91Zl5oREZTrR3yv+tXrrX7G/g=
 github.com/bradfitz/gomemcache v0.0.0-20180710155616-bc664df96737/go.mod h1:PmM6Mmwb0LSuEubjR8N7PtNe1KxZLtOUHtbeikc5h60=

psql/psql_test.go

@@ -425,6 +425,26 @@ func aggFunctionWithFilter(t *testing.T) {
 	}
 }
 
+func queryWithVariables(t *testing.T) {
+	gql := `query {
+		product(id: $PRODUCT_ID, where: { price: { eq: $PRODUCT_PRICE } }) {
+			id
+			name
+		}
+	}`
+
+	sql := `SELECT json_object_agg('product', products) FROM (SELECT row_to_json((SELECT "sel_0" FROM (SELECT "products_0"."id" AS "id", "products_0"."name" AS "name") AS "sel_0")) AS "products" FROM (SELECT "products"."id", "products"."name" FROM "products" WHERE ((("products"."price") > (0)) AND (("products"."price") < (8)) AND (("products"."price") = ('{{PRODUCT_PRICE}}')) AND (("id") = ('{{PRODUCT_ID}}'))) LIMIT ('1') :: integer) AS "products_0" LIMIT ('1') :: integer) AS "done_1337";`
+
+	resSQL, err := compileGQLToPSQL(gql)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if resSQL != sql {
+		t.Fatal(errNotExpected)
+	}
+}
+
 func syntheticTables(t *testing.T) {
 	gql := `query {
 		me {
@@ -457,6 +477,7 @@ func TestCompileGQL(t *testing.T) {
 	t.Run("manyToManyReverse", manyToManyReverse)
 	t.Run("aggFunction", aggFunction)
 	t.Run("aggFunctionWithFilter", aggFunctionWithFilter)
+	t.Run("queryWithVariables", queryWithVariables)
 	t.Run("syntheticTables", syntheticTables)
 }
 

serv/core.go

@@ -2,18 +2,40 @@ package serv
 
 import (
 	"context"
+	"crypto/sha1"
 	"encoding/json"
 	"fmt"
 	"io"
 	"strings"
 	"time"
 
+	"github.com/allegro/bigcache"
+	"github.com/dosco/super-graph/qcode"
 	"github.com/go-pg/pg"
 	"github.com/valyala/fasttemplate"
 )
 
+var (
+	cache, _ = bigcache.NewBigCache(bigcache.DefaultConfig(24 * time.Hour))
+)
+
 func handleReq(ctx context.Context, w io.Writer, req *gqlReq) error {
-	qc, err := qcompile.CompileQuery(req.Query)
+	var key, finalSQL string
+	var qc *qcode.QCode
+
+	var entry []byte
+	var err error
+
+	cacheEnabled := (conf.EnableTracing == false)
+
+	if cacheEnabled {
+		k := sha1.Sum([]byte(req.Query))
+		key = string(k[:])
+		entry, err = cache.Get(key)
+	}
+
+	if len(entry) == 0 || err == bigcache.ErrEntryNotFound {
+		qc, err = qcompile.CompileQuery(req.Query)
 		if err != nil {
 			return err
 		}
@@ -39,7 +61,15 @@ func handleReq(ctx context.Context, w io.Writer, req *gqlReq) error {
 			return err
 		}
 
-	finalSQL := sqlStmt.String()
+		finalSQL = sqlStmt.String()
+
+	} else if err != nil {
+		return err
+
+	} else {
+		finalSQL = string(entry)
+	}
+
 	if conf.DebugLevel > 0 {
 		fmt.Println(finalSQL)
 	}
@@ -55,6 +85,12 @@ func handleReq(ctx context.Context, w io.Writer, req *gqlReq) error {
 	et := time.Now()
 	resp := gqlResp{Data: json.RawMessage(root)}
 
+	if cacheEnabled {
+		if err = cache.Set(key, []byte(finalSQL)); err != nil {
+			return err
+		}
+	}
+
 	if conf.EnableTracing {
 		resp.Extensions = &extensions{newTrace(st, et, qc)}
 	}