Add LogRequest variable to config input (#5197) (#7085)

* Add LogRequest variable to config input (#5197)

Fixes: DGRAPH-1123

This PR adds support for logRequest config param. logRequest can have true/false values. True
value of logRequest enables logging of all requests coming to alphas. False value of logRequest
disables it.
Users will be able to dynamically change this param using graphql admin endpoint.
Sample query:

mutation {
  config(input: {logRequest: true}){
    response {
      code
      message
    }
  }
}
Internally we have added one more field in WorkerOptions(WorkerConfig) called as LogRequest
of int32 type. Value of this field is checked atomically upon every request arrival. If value of
LogRequest is 1, it results in logging of requests.


Co-authored-by: Ashish Goswami <ashish@dgraph.io>
(cherry picked from commit 449c06b)

* fix(GraphQL): don't update cacheMb if not specified by user (GRAPHQL-888) (#7103)

Fixes GRAPHQL-888.
Previously, if you ran this request:
```
$ curl -H "Content-Type: application/json" http://localhost:8080/admin -d '{"query": "mutation {config(input: {logRequest: false}){response {code message}}}"}'
```
Alpha logs would also print this:
```
I1205 22:22:51.684693 2681396 middlewares.go:178] GraphQL admin mutation. Name =  config
I1205 22:22:51.684724 2681396 config.go:38] Got config update through GraphQL admin API
I1205 22:22:51.684810 2681396 worker.go:138] Updating cacheMb to 0
```
Indicating that cacheMb was also updated, even it wasn't specified in the request.

This PR fixes this issue.

(cherry picked from commit c03c327)

# Conflicts:
#	graphql/admin/config.go

Co-authored-by: Animesh Chandra Pathak <animesh@dgraph.io>
Co-authored-by: Abhimanyu Singh Gaur <12651351+abhimanyusinghgaur@users.noreply.github.com>

edgraph/server.go

@@ -808,7 +808,7 @@ func (s *Server) Query(ctx context.Context, req *api.Request) (*api.Response, er
 
 func (s *Server) doQuery(ctx context.Context, req *api.Request, doAuth AuthMode) (
 	resp *api.Response, rerr error) {
-	if glog.V(3) {
+	if bool(glog.V(3)) || worker.LogRequestEnabled() {
 		glog.Infof("Got a query: %+v", req)
 	}
 	isGraphQL, _ := ctx.Value(IsGraphql).(bool)

graphql/admin/admin.go

@@ -221,6 +221,12 @@ const (
 		more than specified here. (default -1 means no set limit)
 		"""
 		lruMb: Float
+
+		"""
+		True value of logRequest enables logging of all the requests coming to alphas.
+		False value of logRequest disables above.
+		"""
+		logRequest: Boolean
 	}
 
 	type ConfigPayload {

graphql/admin/config.go

@@ -27,7 +27,11 @@ import (
 )
 
 type configInput struct {
-	LruMB float64
+	LruMB *float64
+	// LogRequest is used to update WorkerOptions.LogRequest. true value of LogRequest enables
+	// logging of all requests coming to alphas. LogRequest type has been kept as *bool instead of
+	// bool to avoid updating WorkerOptions.LogRequest when it has default value of false.
+	LogRequest *bool
 }
 
 func resolveConfig(ctx context.Context, m schema.Mutation) (*resolve.Resolved, bool) {
@@ -38,9 +42,16 @@ func resolveConfig(ctx context.Context, m schema.Mutation) (*resolve.Resolved, b
 		return emptyResult(m, err), false
 	}
 
-	err = worker.UpdateLruMb(input.LruMB)
-	if err != nil {
-		return emptyResult(m, err), false
+	// update LruMB only when it is specified by user
+	if input.LruMB != nil {
+		if err = worker.UpdateLruMb(*input.LruMB); err != nil {
+			return emptyResult(m, err), false
+		}
+	}
+
+	// input.LogRequest will be nil, when it is not specified explicitly in config request.
+	if input.LogRequest != nil {
+		worker.UpdateLogRequest(*input.LogRequest)
 	}
 
 	return &resolve.Resolved{

worker/worker.go

@@ -24,6 +24,7 @@ import (
 	"math"
 	"net"
 	"sync"
+	"sync/atomic"
 
 	"github.com/dgraph-io/badger/v2"
 	badgerpb "github.com/dgraph-io/badger/v2/pb"
@@ -139,3 +140,18 @@ func UpdateLruMb(memoryMB float64) error {
 	posting.Config.Unlock()
 	return nil
 }
+
+// UpdateLogRequest updates value of x.WorkerConfig.LogRequest.
+func UpdateLogRequest(val bool) {
+	if val {
+		atomic.StoreInt32(&x.WorkerConfig.LogRequest, 1)
+		return
+	}
+
+	atomic.StoreInt32(&x.WorkerConfig.LogRequest, 0)
+}
+
+// LogRequestEnabled returns true if logging of requests is enabled otherwise false.
+func LogRequestEnabled() bool {
+	return atomic.LoadInt32(&x.WorkerConfig.LogRequest) > 0
+}

x/config.go

@@ -82,6 +82,11 @@ type WorkerOptions struct {
 	LudicrousMode bool
 	// BadgerKeyFile is the file containing the key used for encryption. Enterprise only feature.
 	BadgerKeyFile string
+	// LogRequest indicates whether alpha should log all query/mutation requests coming to it.
+	// Ideally LogRequest should be a bool value. But we are reading it using atomics across
+	// queries hence it has been kept as int32. LogRequest value 1 enables logging of requests
+	// coming to alphas and 0 disables it.
+	LogRequest int32
 }
 
 // WorkerConfig stores the global instance of the worker package's options.