added querier

services/querier.go

@@ -0,0 +1,48 @@
+package thegraph
+
+import (
+	"context"
+	"errors"
+	"time"
+)
+
+type RetryQuerier struct {
+	GraphQLQuerier
+	Backoff    time.Duration
+	MaxRetries int
+}
+
+var _ GraphQLQuerier = (*RetryQuerier)(nil)
+
+func NewRetryQuerier(q GraphQLQuerier, backoff time.Duration, maxRetries int) *RetryQuerier {
+	return &RetryQuerier{
+		GraphQLQuerier: q,
+		Backoff:        backoff,
+		MaxRetries:     maxRetries,
+	}
+}
+
+func (q *RetryQuerier) Query(ctx context.Context, query any, variables map[string]any) error {
+
+	retryCount := 0
+	backoff := q.Backoff
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+			if retryCount > q.MaxRetries {
+				return errors.New("max retries exceeded")
+			}
+			retryCount++
+
+			err := q.GraphQLQuerier.Query(ctx, query, variables)
+			if err == nil {
+				return nil
+			}
+
+			time.Sleep(backoff)
+			backoff *= 2
+		}
+	}
+}