Add kafka and postgres clients to vendor directory

vendor/src/github.com/eapache/go-resiliency/breaker/README.md

@@ -0,0 +1,34 @@
+circuit-breaker
+===============
+
+[![Build Status](https://travis-ci.org/eapache/go-resiliency.svg?branch=master)](https://travis-ci.org/eapache/go-resiliency)
+[![GoDoc](https://godoc.org/github.com/eapache/go-resiliency/breaker?status.svg)](https://godoc.org/github.com/eapache/go-resiliency/breaker)
+[![Code of Conduct](https://img.shields.io/badge/code%20of%20conduct-active-blue.svg)](https://eapache.github.io/conduct.html)
+
+The circuit-breaker resiliency pattern for golang.
+
+Creating a breaker takes three parameters:
+- error threshold (for opening the breaker)
+- success threshold (for closing the breaker)
+- timeout (how long to keep the breaker open)
+
+```go
+b := breaker.New(3, 1, 5*time.Second)
+
+for {
+	result := b.Run(func() error {
+		// communicate with some external service and
+		// return an error if the communication failed
+		return nil
+	})
+
+	switch result {
+	case nil:
+		// success!
+	case breaker.ErrBreakerOpen:
+		// our function wasn't run because the breaker was open
+	default:
+		// some other error
+	}
+}
+```

vendor/src/github.com/eapache/go-resiliency/breaker/breaker.go

@@ -0,0 +1,161 @@
+// Package breaker implements the circuit-breaker resiliency pattern for Go.
+package breaker
+
+import (
+	"errors"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+// ErrBreakerOpen is the error returned from Run() when the function is not executed
+// because the breaker is currently open.
+var ErrBreakerOpen = errors.New("circuit breaker is open")
+
+const (
+	closed uint32 = iota
+	open
+	halfOpen
+)
+
+// Breaker implements the circuit-breaker resiliency pattern
+type Breaker struct {
+	errorThreshold, successThreshold int
+	timeout                          time.Duration
+
+	lock              sync.Mutex
+	state             uint32
+	errors, successes int
+	lastError         time.Time
+}
+
+// New constructs a new circuit-breaker that starts closed.
+// From closed, the breaker opens if "errorThreshold" errors are seen
+// without an error-free period of at least "timeout". From open, the
+// breaker half-closes after "timeout". From half-open, the breaker closes
+// after "successThreshold" consecutive successes, or opens on a single error.
+func New(errorThreshold, successThreshold int, timeout time.Duration) *Breaker {
+	return &Breaker{
+		errorThreshold:   errorThreshold,
+		successThreshold: successThreshold,
+		timeout:          timeout,
+	}
+}
+
+// Run will either return ErrBreakerOpen immediately if the circuit-breaker is
+// already open, or it will run the given function and pass along its return
+// value. It is safe to call Run concurrently on the same Breaker.
+func (b *Breaker) Run(work func() error) error {
+	state := atomic.LoadUint32(&b.state)
+
+	if state == open {
+		return ErrBreakerOpen
+	}
+
+	return b.doWork(state, work)
+}
+
+// Go will either return ErrBreakerOpen immediately if the circuit-breaker is
+// already open, or it will run the given function in a separate goroutine.
+// If the function is run, Go will return nil immediately, and will *not* return
+// the return value of the function. It is safe to call Go concurrently on the
+// same Breaker.
+func (b *Breaker) Go(work func() error) error {
+	state := atomic.LoadUint32(&b.state)
+
+	if state == open {
+		return ErrBreakerOpen
+	}
+
+	// errcheck complains about ignoring the error return value, but
+	// that's on purpose; if you want an error from a goroutine you have to
+	// get it over a channel or something
+	go b.doWork(state, work)
+
+	return nil
+}
+
+func (b *Breaker) doWork(state uint32, work func() error) error {
+	var panicValue interface{}
+
+	result := func() error {
+		defer func() {
+			panicValue = recover()
+		}()
+		return work()
+	}()
+
+	if result == nil && panicValue == nil && state == closed {
+		// short-circuit the normal, success path without contending
+		// on the lock
+		return nil
+	}
+
+	// oh well, I guess we have to contend on the lock
+	b.processResult(result, panicValue)
+
+	if panicValue != nil {
+		// as close as Go lets us come to a "rethrow" although unfortunately
+		// we lose the original panicing location
+		panic(panicValue)
+	}
+
+	return result
+}
+
+func (b *Breaker) processResult(result error, panicValue interface{}) {
+	b.lock.Lock()
+	defer b.lock.Unlock()
+
+	if result == nil && panicValue == nil {
+		if b.state == halfOpen {
+			b.successes++
+			if b.successes == b.successThreshold {
+				b.closeBreaker()
+			}
+		}
+	} else {
+		if b.errors > 0 {
+			expiry := b.lastError.Add(b.timeout)
+			if time.Now().After(expiry) {
+				b.errors = 0
+			}
+		}
+
+		switch b.state {
+		case closed:
+			b.errors++
+			if b.errors == b.errorThreshold {
+				b.openBreaker()
+			} else {
+				b.lastError = time.Now()
+			}
+		case halfOpen:
+			b.openBreaker()
+		}
+	}
+}
+
+func (b *Breaker) openBreaker() {
+	b.changeState(open)
+	go b.timer()
+}
+
+func (b *Breaker) closeBreaker() {
+	b.changeState(closed)
+}
+
+func (b *Breaker) timer() {
+	time.Sleep(b.timeout)
+
+	b.lock.Lock()
+	defer b.lock.Unlock()
+
+	b.changeState(halfOpen)
+}
+
+func (b *Breaker) changeState(newState uint32) {
+	b.errors = 0
+	b.successes = 0
+	atomic.StoreUint32(&b.state, newState)
+}

vendor/src/github.com/eapache/go-resiliency/breaker/breaker_test.go

@@ -0,0 +1,196 @@
+package breaker
+
+import (
+	"errors"
+	"testing"
+	"time"
+)
+
+var errSomeError = errors.New("errSomeError")
+
+func alwaysPanics() error {
+	panic("foo")
+}
+
+func returnsError() error {
+	return errSomeError
+}
+
+func returnsSuccess() error {
+	return nil
+}
+
+func TestBreakerErrorExpiry(t *testing.T) {
+	breaker := New(2, 1, 1*time.Second)
+
+	for i := 0; i < 3; i++ {
+		if err := breaker.Run(returnsError); err != errSomeError {
+			t.Error(err)
+		}
+		time.Sleep(1 * time.Second)
+	}
+
+	for i := 0; i < 3; i++ {
+		if err := breaker.Go(returnsError); err != nil {
+			t.Error(err)
+		}
+		time.Sleep(1 * time.Second)
+	}
+}
+
+func TestBreakerPanicsCountAsErrors(t *testing.T) {
+	breaker := New(3, 2, 1*time.Second)
+
+	// three errors opens the breaker
+	for i := 0; i < 3; i++ {
+		func() {
+			defer func() {
+				val := recover()
+				if val.(string) != "foo" {
+					t.Error("incorrect panic")
+				}
+			}()
+			if err := breaker.Run(alwaysPanics); err != nil {
+				t.Error(err)
+			}
+			t.Error("shouldn't get here")
+		}()
+	}
+
+	// breaker is open
+	for i := 0; i < 5; i++ {
+		if err := breaker.Run(returnsError); err != ErrBreakerOpen {
+			t.Error(err)
+		}
+	}
+}
+
+func TestBreakerStateTransitions(t *testing.T) {
+	breaker := New(3, 2, 1*time.Second)
+
+	// three errors opens the breaker
+	for i := 0; i < 3; i++ {
+		if err := breaker.Run(returnsError); err != errSomeError {
+			t.Error(err)
+		}
+	}
+
+	// breaker is open
+	for i := 0; i < 5; i++ {
+		if err := breaker.Run(returnsError); err != ErrBreakerOpen {
+			t.Error(err)
+		}
+	}
+
+	// wait for it to half-close
+	time.Sleep(2 * time.Second)
+	// one success works, but is not enough to fully close
+	if err := breaker.Run(returnsSuccess); err != nil {
+		t.Error(err)
+	}
+	// error works, but re-opens immediately
+	if err := breaker.Run(returnsError); err != errSomeError {
+		t.Error(err)
+	}
+	// breaker is open
+	if err := breaker.Run(returnsError); err != ErrBreakerOpen {
+		t.Error(err)
+	}
+
+	// wait for it to half-close
+	time.Sleep(2 * time.Second)
+	// two successes is enough to close it for good
+	for i := 0; i < 2; i++ {
+		if err := breaker.Run(returnsSuccess); err != nil {
+			t.Error(err)
+		}
+	}
+	// error works
+	if err := breaker.Run(returnsError); err != errSomeError {
+		t.Error(err)
+	}
+	// breaker is still closed
+	if err := breaker.Run(returnsSuccess); err != nil {
+		t.Error(err)
+	}
+}
+
+func TestBreakerAsyncStateTransitions(t *testing.T) {
+	breaker := New(3, 2, 1*time.Second)
+
+	// three errors opens the breaker
+	for i := 0; i < 3; i++ {
+		if err := breaker.Go(returnsError); err != nil {
+			t.Error(err)
+		}
+	}
+
+	// just enough to yield the scheduler and let the goroutines work off
+	time.Sleep(1 * time.Millisecond)
+
+	// breaker is open
+	for i := 0; i < 5; i++ {
+		if err := breaker.Go(returnsError); err != ErrBreakerOpen {
+			t.Error(err)
+		}
+	}
+
+	// wait for it to half-close
+	time.Sleep(2 * time.Second)
+	// one success works, but is not enough to fully close
+	if err := breaker.Go(returnsSuccess); err != nil {
+		t.Error(err)
+	}
+	// error works, but re-opens immediately
+	if err := breaker.Go(returnsError); err != nil {
+		t.Error(err)
+	}
+	// just enough to yield the scheduler and let the goroutines work off
+	time.Sleep(1 * time.Millisecond)
+	// breaker is open
+	if err := breaker.Go(returnsError); err != ErrBreakerOpen {
+		t.Error(err)
+	}
+
+	// wait for it to half-close
+	time.Sleep(2 * time.Second)
+	// two successes is enough to close it for good
+	for i := 0; i < 2; i++ {
+		if err := breaker.Go(returnsSuccess); err != nil {
+			t.Error(err)
+		}
+	}
+	// just enough to yield the scheduler and let the goroutines work off
+	time.Sleep(1 * time.Millisecond)
+	// error works
+	if err := breaker.Go(returnsError); err != nil {
+		t.Error(err)
+	}
+	// just enough to yield the scheduler and let the goroutines work off
+	time.Sleep(1 * time.Millisecond)
+	// breaker is still closed
+	if err := breaker.Go(returnsSuccess); err != nil {
+		t.Error(err)
+	}
+}
+
+func ExampleBreaker() {
+	breaker := New(3, 1, 5*time.Second)
+
+	for {
+		result := breaker.Run(func() error {
+			// communicate with some external service and
+			// return an error if the communication failed
+			return nil
+		})
+
+		switch result {
+		case nil:
+			// success!
+		case ErrBreakerOpen:
+			// our function wasn't run because the breaker was open
+		default:
+			// some other error
+		}
+	}
+}

vendor/src/github.com/eapache/go-xerial-snappy/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Evan Huus
+
+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.

vendor/src/github.com/eapache/go-xerial-snappy/README.md

@@ -0,0 +1,13 @@
+# go-xerial-snappy
+
+[![Build Status](https://travis-ci.org/eapache/go-xerial-snappy.svg?branch=master)](https://travis-ci.org/eapache/go-xerial-snappy)
+
+Xerial-compatible Snappy framing support for golang.
+
+Packages using Xerial for snappy encoding use a framing format incompatible with
+basically everything else in existence. This package wraps Go's built-in snappy
+package to support it.
+
+Apps that use this format include Apache Kafka (see
+https://github.com/dpkp/kafka-python/issues/126#issuecomment-35478921 for
+details).

vendor/src/github.com/eapache/go-xerial-snappy/snappy.go

@@ -0,0 +1,43 @@
+package snappy
+
+import (
+	"bytes"
+	"encoding/binary"
+
+	master "github.com/golang/snappy"
+)
+
+var xerialHeader = []byte{130, 83, 78, 65, 80, 80, 89, 0}
+
+// Encode encodes data as snappy with no framing header.
+func Encode(src []byte) []byte {
+	return master.Encode(nil, src)
+}
+
+// Decode decodes snappy data whether it is traditional unframed
+// or includes the xerial framing format.
+func Decode(src []byte) ([]byte, error) {
+	if !bytes.Equal(src[:8], xerialHeader) {
+		return master.Decode(nil, src)
+	}
+
+	var (
+		pos   = uint32(16)
+		max   = uint32(len(src))
+		dst   = make([]byte, 0, len(src))
+		chunk []byte
+		err   error
+	)
+	for pos < max {
+		size := binary.BigEndian.Uint32(src[pos : pos+4])
+		pos += 4
+
+		chunk, err = master.Decode(chunk, src[pos:pos+size])
+		if err != nil {
+			return nil, err
+		}
+		pos += size
+		dst = append(dst, chunk...)
+	}
+	return dst, nil
+}

vendor/src/github.com/eapache/queue/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 Evan Huus
+
+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.

vendor/src/github.com/eapache/queue/README.md

@@ -0,0 +1,16 @@
+Queue
+=====
+
+[![Build Status](https://travis-ci.org/eapache/queue.svg)](https://travis-ci.org/eapache/queue)
+[![GoDoc](https://godoc.org/github.com/eapache/queue?status.png)](https://godoc.org/github.com/eapache/queue)
+[![Code of Conduct](https://img.shields.io/badge/code%20of%20conduct-active-blue.svg)](https://eapache.github.io/conduct.html)
+
+A fast Golang queue using a ring-buffer, based on the version suggested by Dariusz Górecki.
+Using this instead of other, simpler, queue implementations (slice+append or linked list) provides
+substantial memory and time benefits, and fewer GC pauses.
+
+The queue implemented here is as fast as it is in part because it is *not* thread-safe.
+
+Follows semantic versioning using https://gopkg.in/ - import from
+[`gopkg.in/eapache/queue.v1`](https://gopkg.in/eapache/queue.v1)
+for guaranteed API stability.

vendor/src/github.com/eapache/queue/queue.go

@@ -0,0 +1,102 @@
+/*
+Package queue provides a fast, ring-buffer queue based on the version suggested by Dariusz Górecki.
+Using this instead of other, simpler, queue implementations (slice+append or linked list) provides
+substantial memory and time benefits, and fewer GC pauses.
+
+The queue implemented here is as fast as it is for an additional reason: it is *not* thread-safe.
+*/
+package queue
+
+// minQueueLen is smallest capacity that queue may have.
+// Must be power of 2 for bitwise modulus: x % n == x & (n - 1).
+const minQueueLen = 16
+
+// Queue represents a single instance of the queue data structure.
+type Queue struct {
+	buf               []interface{}
+	head, tail, count int
+}
+
+// New constructs and returns a new Queue.
+func New() *Queue {
+	return &Queue{
+		buf: make([]interface{}, minQueueLen),
+	}
+}
+
+// Length returns the number of elements currently stored in the queue.
+func (q *Queue) Length() int {
+	return q.count
+}
+
+// resizes the queue to fit exactly twice its current contents
+// this can result in shrinking if the queue is less than half-full
+func (q *Queue) resize() {
+	newBuf := make([]interface{}, q.count<<1)
+
+	if q.tail > q.head {
+		copy(newBuf, q.buf[q.head:q.tail])
+	} else {
+		n := copy(newBuf, q.buf[q.head:])
+		copy(newBuf[n:], q.buf[:q.tail])
+	}
+
+	q.head = 0
+	q.tail = q.count
+	q.buf = newBuf
+}
+
+// Add puts an element on the end of the queue.
+func (q *Queue) Add(elem interface{}) {
+	if q.count == len(q.buf) {
+		q.resize()
+	}
+
+	q.buf[q.tail] = elem
+	// bitwise modulus
+	q.tail = (q.tail + 1) & (len(q.buf) - 1)
+	q.count++
+}
+
+// Peek returns the element at the head of the queue. This call panics
+// if the queue is empty.
+func (q *Queue) Peek() interface{} {
+	if q.count <= 0 {
+		panic("queue: Peek() called on empty queue")
+	}
+	return q.buf[q.head]
+}
+
+// Get returns the element at index i in the queue. If the index is
+// invalid, the call will panic. This method accepts both positive and
+// negative index values. Index 0 refers to the first element, and
+// index -1 refers to the last.
+func (q *Queue) Get(i int) interface{} {
+	// If indexing backwards, convert to positive index.
+	if i < 0 {
+		i += q.count
+	}
+	if i < 0 || i >= q.count {
+		panic("queue: Get() called with index out of range")
+	}
+	// bitwise modulus
+	return q.buf[(q.head+i)&(len(q.buf)-1)]
+}
+
+// Remove removes and returns the element from the front of the queue. If the
+// queue is empty, the call will panic.
+func (q *Queue) Remove() interface{} {
+	if q.count <= 0 {
+		panic("queue: Remove() called on empty queue")
+	}
+	ret := q.buf[q.head]
+	q.buf[q.head] = nil
+	// bitwise modulus
+	q.head = (q.head + 1) & (len(q.buf) - 1)
+	q.count--
+	// Resize down if buffer 1/4 full.
+	if len(q.buf) > minQueueLen && (q.count<<2) == len(q.buf) {
+		q.resize()
+	}
+	return ret
+}

vendor/src/github.com/eapache/queue/queue_test.go

@@ -0,0 +1,178 @@
+package queue
+
+import "testing"
+
+func TestQueueSimple(t *testing.T) {
+	q := New()
+
+	for i := 0; i < minQueueLen; i++ {
+		q.Add(i)
+	}
+	for i := 0; i < minQueueLen; i++ {
+		if q.Peek().(int) != i {
+			t.Error("peek", i, "had value", q.Peek())
+		}
+		x := q.Remove()
+		if x != i {
+			t.Error("remove", i, "had value", x)
+		}
+	}
+}
+
+func TestQueueWrapping(t *testing.T) {
+	q := New()
+
+	for i := 0; i < minQueueLen; i++ {
+		q.Add(i)
+	}
+	for i := 0; i < 3; i++ {
+		q.Remove()
+		q.Add(minQueueLen + i)
+	}
+
+	for i := 0; i < minQueueLen; i++ {
+		if q.Peek().(int) != i+3 {
+			t.Error("peek", i, "had value", q.Peek())
+		}
+		q.Remove()
+	}
+}
+
+func TestQueueLength(t *testing.T) {
+	q := New()
+
+	if q.Length() != 0 {
+		t.Error("empty queue length not 0")
+	}
+
+	for i := 0; i < 1000; i++ {
+		q.Add(i)
+		if q.Length() != i+1 {
+			t.Error("adding: queue with", i, "elements has length", q.Length())
+		}
+	}
+	for i := 0; i < 1000; i++ {
+		q.Remove()
+		if q.Length() != 1000-i-1 {
+			t.Error("removing: queue with", 1000-i-i, "elements has length", q.Length())
+		}
+	}
+}
+
+func TestQueueGet(t *testing.T) {
+	q := New()
+
+	for i := 0; i < 1000; i++ {
+		q.Add(i)
+		for j := 0; j < q.Length(); j++ {
+			if q.Get(j).(int) != j {
+				t.Errorf("index %d doesn't contain %d", j, j)
+			}
+		}
+	}
+}
+
+func TestQueueGetNegative(t *testing.T) {
+	q := New()
+
+	for i := 0; i < 1000; i++ {
+		q.Add(i)
+		for j := 1; j <= q.Length(); j++ {
+			if q.Get(-j).(int) != q.Length()-j {
+				t.Errorf("index %d doesn't contain %d", -j, q.Length()-j)
+			}
+		}
+	}
+}
+
+func TestQueueGetOutOfRangePanics(t *testing.T) {
+	q := New()
+
+	q.Add(1)
+	q.Add(2)
+	q.Add(3)
+
+	assertPanics(t, "should panic when negative index", func() {
+		q.Get(-4)
+	})
+
+	assertPanics(t, "should panic when index greater than length", func() {
+		q.Get(4)
+	})
+}
+
+func TestQueuePeekOutOfRangePanics(t *testing.T) {
+	q := New()
+
+	assertPanics(t, "should panic when peeking empty queue", func() {
+		q.Peek()
+	})
+
+	q.Add(1)
+	q.Remove()
+
+	assertPanics(t, "should panic when peeking emptied queue", func() {
+		q.Peek()
+	})
+}
+
+func TestQueueRemoveOutOfRangePanics(t *testing.T) {
+	q := New()
+
+	assertPanics(t, "should panic when removing empty queue", func() {
+		q.Remove()
+	})
+
+	q.Add(1)
+	q.Remove()
+
+	assertPanics(t, "should panic when removing emptied queue", func() {
+		q.Remove()
+	})
+}
+
+func assertPanics(t *testing.T, name string, f func()) {
+	defer func() {
+		if r := recover(); r == nil {
+			t.Errorf("%s: didn't panic as expected", name)
+		}
+	}()
+
+	f()
+}
+
+// General warning: Go's benchmark utility (go test -bench .) increases the number of
+// iterations until the benchmarks take a reasonable amount of time to run; memory usage
+// is *NOT* considered. On my machine, these benchmarks hit around ~1GB before they've had
+// enough, but if you have less than that available and start swapping, then all bets are off.
+
+func BenchmarkQueueSerial(b *testing.B) {
+	q := New()
+	for i := 0; i < b.N; i++ {
+		q.Add(nil)
+	}
+	for i := 0; i < b.N; i++ {
+		q.Peek()
+		q.Remove()
+	}
+}
+
+func BenchmarkQueueGet(b *testing.B) {
+	q := New()
+	for i := 0; i < b.N; i++ {
+		q.Add(i)
+	}
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		q.Get(i)
+	}
+}
+
+func BenchmarkQueueTickTock(b *testing.B) {
+	q := New()
+	for i := 0; i < b.N; i++ {
+		q.Add(nil)
+		q.Peek()
+		q.Remove()
+	}
+}