accounts: start adding request ID to context

In preperation for the trace logging we want to implement in an upcoming
commit (where logs for requests & responsescan be linked via their
request ID), we start adding the request ID to an intercepted account
request/response in this commit.

Author: ellemouton

accounts/checkers_test.go

@@ -112,6 +112,8 @@ func TestAccountChecker(t *testing.T) {
 func TestAccountCheckers(t *testing.T) {
 	t.Parallel()
 
+	const reqID = uint64(55)
+
 	testCases := []struct {
 		name    string
 		fullURI string
@@ -416,9 +418,8 @@ func TestAccountCheckers(t *testing.T) {
 				Invoices: make(AccountInvoices),
 				Payments: make(AccountPayments),
 			}
-			ctx := AddToContext(
-				context.Background(), KeyAccount, acct,
-			)
+			ctx := AddAccountToContext(context.Background(), acct)
+			ctx = AddRequestIDToContext(ctx, reqID)
 
 			// Is a setup call required to initialize initial
 			// conditions?

accounts/context.go

@@ -18,18 +18,23 @@ var (
 	// KeyAccount is the key under which we store the account in the request
 	// context.
 	KeyAccount = ContextKey{"account"}
+
+	// KeyRequestID is the key under which we store the middleware request
+	// ID.
+	KeyRequestID = ContextKey{"request_id"}
 )
 
 // FromContext tries to extract a value from the given context.
 func FromContext(ctx context.Context, key ContextKey) interface{} {
 	return ctx.Value(key)
 }
 
-// AddToContext adds the given value to the context for easy retrieval later on.
-func AddToContext(ctx context.Context, key ContextKey,
+// AddAccountToContext adds the given value to the context for easy retrieval
+// later on.
+func AddAccountToContext(ctx context.Context,
 	value *OffChainBalanceAccount) context.Context {
 
-	return context.WithValue(ctx, key, value)
+	return context.WithValue(ctx, KeyAccount, value)
 }
 
 // AccountFromContext attempts to extract an account from the given context.
@@ -46,3 +51,24 @@ func AccountFromContext(ctx context.Context) (*OffChainBalanceAccount, error) {
 
 	return acct, nil
 }
+
+// AddRequestIDToContext adds the given request ID to the context for easy
+// retrieval later on.
+func AddRequestIDToContext(ctx context.Context, value uint64) context.Context {
+	return context.WithValue(ctx, KeyRequestID, value)
+}
+
+// RequestIDFromContext attempts to extract a request ID from the given context.
+func RequestIDFromContext(ctx context.Context) (uint64, error) {
+	val := FromContext(ctx, KeyRequestID)
+	if val == nil {
+		return 0, fmt.Errorf("no request ID found in context")
+	}
+
+	reqID, ok := val.(uint64)
+	if !ok {
+		return 0, fmt.Errorf("invalid request ID value in context")
+	}
+
+	return reqID, nil
+}

accounts/interceptor.go

@@ -101,9 +101,10 @@ func (s *InterceptorService) Intercept(ctx context.Context,
 		)
 	}
 
-	// We now add the account to the incoming context to give each checker
-	// access to it if required.
-	ctxAccount := AddToContext(ctx, KeyAccount, acct)
+	// We now add the account and request ID to the incoming context to give
+	// each checker access to them if required.
+	ctx = AddAccountToContext(ctx, acct)
+	ctx = AddRequestIDToContext(ctx, req.RequestId)
 
 	switch r := req.InterceptType.(type) {
 	// In the authentication phase we just check that the account hasn't
@@ -120,7 +121,7 @@ func (s *InterceptorService) Intercept(ctx context.Context,
 		}
 
 		return mid.RPCErr(req, s.checkers.checkIncomingRequest(
-			ctxAccount, r.Request.MethodFullUri, msg,
+			ctx, r.Request.MethodFullUri, msg,
 		))
 
 	// Parse and possibly manipulate outgoing responses.
@@ -131,7 +132,7 @@ func (s *InterceptorService) Intercept(ctx context.Context,
 		}
 
 		replacement, err := s.checkers.replaceOutgoingResponse(
-			ctxAccount, r.Response.MethodFullUri, msg,
+			ctx, r.Response.MethodFullUri, msg,
 		)
 		if err != nil {
 			return mid.RPCErr(req, err)