Merge pull request #53 from celenium-io/feature/gas-estimation

Feature: gas tracker endpoint

cmd/api/gas/data.go

@@ -0,0 +1,76 @@
+// SPDX-FileCopyrightText: 2023 PK Lab AG <contact@pklab.io>
+// SPDX-License-Identifier: MIT
+
+package gas
+
+import (
+	"sync"
+
+	"github.com/shopspring/decimal"
+)
+
+type GasPrice struct {
+	Slow   string
+	Median string
+	Fast   string
+}
+
+type info struct {
+	Height       uint64
+	Percentiles  []decimal.Decimal
+	TxCount      int64
+	GasUsed      int64
+	GasWanted    int64
+	Fee          decimal.Decimal
+	GasUsedRatio decimal.Decimal
+}
+
+type queue struct {
+	data     []info
+	capacity int
+	mx       *sync.RWMutex
+}
+
+func newQueue(capacity int) *queue {
+	return &queue{
+		data:     make([]info, 0),
+		capacity: capacity,
+		mx:       new(sync.RWMutex),
+	}
+}
+
+func (q *queue) Push(item info) {
+	q.mx.Lock()
+	if len(q.data) == q.capacity {
+		q.data = q.data[:len(q.data)-2]
+	}
+	q.data = append([]info{item}, q.data...)
+	q.mx.Unlock()
+}
+
+func (q *queue) Range(handler func(item info) (bool, error)) error {
+	if handler == nil {
+		return nil
+	}
+
+	q.mx.RLock()
+	defer q.mx.RUnlock()
+
+	for i := range q.data {
+		br, err := handler(q.data[i])
+		if err != nil {
+			return err
+		}
+		if br {
+			return nil
+		}
+	}
+	return nil
+}
+
+func (q *queue) Size() int {
+	q.mx.RLock()
+	defer q.mx.RUnlock()
+
+	return len(q.data)
+}

cmd/api/gas/data_test.go

@@ -0,0 +1,29 @@
+// SPDX-FileCopyrightText: 2023 PK Lab AG <contact@pklab.io>
+// SPDX-License-Identifier: MIT
+
+package gas
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestQueue(t *testing.T) {
+	q := newQueue(10)
+
+	for i := 0; i < 10000; i++ {
+		q.Push(info{
+			Height:  uint64(i),
+			TxCount: 2,
+		})
+	}
+
+	var totalTx int64
+	err := q.Range(func(item info) (bool, error) {
+		totalTx += item.TxCount
+		return false, nil
+	})
+	require.NoError(t, err)
+	require.EqualValues(t, 20, totalTx)
+}