Initial Commit

Author: Dean Karn

.github/workflows/go.yml

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+name: Lint & Test
+on: [push, pull_request]
+jobs:
+  test:
+    strategy:
+      matrix:
+        go-version: [1.14.x]
+        platform: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v1
+        with:
+          go-version: ${{ matrix.go-version }}
+
+      - name: Priming Cache
+        uses: actions/cache@v1
+        with:
+          path: ~/go/pkg/mod
+          key: ${{ runner.os }}-v1-go-${{ hashFiles('**/go.sum') }}
+          restore-keys: |
+            ${{ runner.os }}-v1-go-
+
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Lint
+        if: matrix.platform == 'ubuntu-latest' && matrix.go-version == '1.14.x'
+        run: |
+          export PATH=$PATH:$(go env GOPATH)/bin # temporary fix. See https://github.com/actions/setup-go/issues/14
+          go get -u golang.org/x/lint/golint
+          golint -set_exit_status ./...
+
+      - name: Test
+        run: go test ./...

.gitignore

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+# Created by .ignore support plugin (hsz.mobi)
+### Go template
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2020 Go Playground
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+## Package backoff-sys
+
+<img align="right" src="https://raw.githubusercontent.com/go-playground/backoff-sys/master/logo.jpg">![Project status](https://img.shields.io/badge/version-1.0.0-green.svg)
+[![Actions Status](https://github.com/go-playground/backoff-sys/workflows/Lint%20%26%20Test/badge.svg)](https://github.com/go-playground/backoff-sys/actions)
+[![GoDoc](https://godoc.org/github.com/go-playground/backoff-sys?status.svg)](https://pkg.go.dev/github.com/go-playground/backoff-sys)
+![License](https://img.shields.io/dub/l/vibe-d.svg)
+
+Package backoff-sys provides the bare building blocks for backing off and can be used to build more complex backoff packages, but this is likely enough.
+This includes:
+- [x] Exponential backoff, with jitter
+- [ ] Linear backoff, with jitter
+
+Example
+-------
+```go
+// go run _examples/exponential/main.go
+package main
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/go-playground/backoff-sys"
+)
+
+func main() {
+	bo := backoff.NewExponential().Init()
+	for i := 0; i < 5; i++ {
+		err := fallible()
+		if err != nil {
+			d := bo.Duration(i)
+			fmt.Printf("Waiting: %s\n", d)
+			time.Sleep(d)
+			continue
+		}
+	}
+}
+
+func fallible() error {
+	return errors.New("failed")
+}
+```
+
+License
+------
+Distributed under MIT License, please see license file in code for more details.

_examples/exponential/main.go

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+package main
+
+import (
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/go-playground/backoff-sys"
+)
+
+func main() {
+	bo := backoff.NewExponential().Init()
+	for i := 0; i < 5; i++ {
+		err := fallible()
+		if err != nil {
+			d := bo.Duration(i)
+			fmt.Printf("Waiting: %s\n", d)
+			time.Sleep(d)
+			continue
+		}
+	}
+}
+
+func fallible() error {
+	return errors.New("failed")
+}

exponential.go

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+package backoff
+
+import (
+	"math"
+	"math/rand"
+	"time"
+)
+
+// ExponentialBuilder helps to build the final exponential backoff entity
+type ExponentialBuilder struct {
+	factor   float64
+	interval time.Duration
+	jitter   time.Duration
+}
+
+// NewExponential create a new exponential backoff builder with sane defaults.
+func NewExponential() ExponentialBuilder {
+	return ExponentialBuilder{
+		factor:   1.75,
+		interval: time.Second,
+		jitter:   time.Millisecond * 250,
+	}
+}
+
+// Factor sets a factor for the backoff algorithm.
+func (e ExponentialBuilder) Factor(factor float64) ExponentialBuilder {
+	e.factor = factor
+	return e
+}
+
+// Interval sets base wait interval for the backoff algorithm.
+func (e ExponentialBuilder) Interval(interval time.Duration) ExponentialBuilder {
+	e.interval = interval
+	return e
+}
+
+// Jitter sets the maximum jitter for the backoff algorithm.
+func (e ExponentialBuilder) Jitter(jitter time.Duration) ExponentialBuilder {
+	e.jitter = jitter
+	return e
+}
+
+// Init returns a read-only(thread safe) Exponential backoff entity for use.
+func (e ExponentialBuilder) Init() Exponential {
+	return Exponential{
+		factor:   e.factor,
+		interval: float64(e.interval),
+		jitter:   int64(e.jitter),
+	}
+}
+
+// Exponential is the final read-only(thread safe) backoff entity
+type Exponential struct {
+	factor   float64
+	interval float64
+	jitter   int64
+}
+
+// Duration accepts attempt and returns the backoff duration o sleep for.
+func (e Exponential) Duration(attempt int) time.Duration {
+	d := int64(math.Pow(e.factor, float64(attempt)) * e.interval)
+	if e.jitter <= 0 {
+		return time.Duration(d)
+	}
+	jitter := rand.Int63n(e.jitter)
+	return time.Duration(d + jitter)
+}

go.mod

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+module github.com/go-playground/backoff-sys
+
+go 1.14