2 files changed, 230 insertions, 0 deletions
diff --git a/vendor/github.com/getlantern/ops/ops.go b/vendor/github.com/getlantern/ops/ops.go
new file mode 100644
index 0000000..136302d
--- /dev/null
+++ b/vendor/github.com/getlantern/ops/ops.go
@@ -0,0 +1,154 @@
+// Package ops provides a facility for tracking the processing of operations,
+// including contextual metadata about the operation and their final success or
+// failure. An op is assumed to have succeeded if by the time of calling Exit()
+// no errors have been reported. The final status can be reported to a metrics
+// facility.
+package ops
+
+import (
+	"sync"
+	"sync/atomic"
+
+	"github.com/getlantern/context"
+)
+
+var (
+	cm             = context.NewManager()
+	reporters      []Reporter
+	reportersMutex sync.RWMutex
+)
+
+// Reporter is a function that reports the success or failure of an Op. If
+// failure is nil, the Op can be considered successful.
+type Reporter func(failure error, ctx map[string]interface{})
+
+// Op represents an operation that's being performed. It mimics the API of
+// context.Context.
+type Op interface {
+	// Begin marks the beginning of an Op under this Op.
+	Begin(name string) Op
+
+	// Go starts the given function on a new goroutine.
+	Go(fn func())
+
+	// End marks the end of this op, at which point the Op will report its success
+	// or failure to all registered Reporters.
+	End()
+
+	// Cancel cancels this op so that even if End() is called later, it will not
+	// report its success or failure.
+	Cancel()
+
+	// Set puts a key->value pair into the current Op's context.
+	Set(key string, value interface{}) Op
+
+	// SetDynamic puts a key->value pair into the current Op's context, where the
+	// value is generated by a function that gets evaluated at every Read.
+	SetDynamic(key string, valueFN func() interface{}) Op
+
+	// FailIf marks this Op as failed if the given err is not nil. If FailIf is
+	// called multiple times, the latest error will be reported as the failure.
+	// Returns the original error for convenient chaining.
+	FailIf(err error) error
+}
+
+type op struct {
+	ctx      context.Context
+	canceled bool
+	failure  atomic.Value
+}
+
+// RegisterReporter registers the given reporter.
+func RegisterReporter(reporter Reporter) {
+	reportersMutex.Lock()
+	reporters = append(reporters, reporter)
+	reportersMutex.Unlock()
+}
+
+// Begin marks the beginning of a new Op.
+func Begin(name string) Op {
+	return &op{ctx: cm.Enter().Put("op", name).PutIfAbsent("root_op", name)}
+}
+
+func (o *op) Begin(name string) Op {
+	return &op{ctx: o.ctx.Enter().Put("op", name).PutIfAbsent("root_op", name)}
+}
+
+func (o *op) Go(fn func()) {
+	o.ctx.Go(fn)
+}
+
+// Go mimics the method from context.Manager.
+func Go(fn func()) {
+	cm.Go(fn)
+}
+
+func (o *op) Cancel() {
+	o.canceled = true
+}
+
+func (o *op) End() {
+	if o.canceled {
+		return
+	}
+
+	var reportersCopy []Reporter
+	reportersMutex.RLock()
+	if len(reporters) > 0 {
+		reportersCopy = make([]Reporter, len(reporters))
+		copy(reportersCopy, reporters)
+	}
+	reportersMutex.RUnlock()
+
+	if len(reportersCopy) > 0 {
+		var failure error
+		_failure := o.failure.Load()
+		ctx := o.ctx.AsMap(_failure, true)
+		if _failure != nil {
+			failure = _failure.(error)
+			_, errorSet := ctx["error"]
+			if !errorSet {
+				ctx["error"] = failure.Error()
+			}
+		}
+		for _, reporter := range reportersCopy {
+			reporter(failure, ctx)
+		}
+	}
+
+	o.ctx.Exit()
+}
+
+func (o *op) Set(key string, value interface{}) Op {
+	o.ctx.Put(key, value)
+	return o
+}
+
+// SetGlobal puts a key->value pair into the global context, which is inherited
+// by all Ops.
+func SetGlobal(key string, value interface{}) {
+	cm.PutGlobal(key, value)
+}
+
+func (o *op) SetDynamic(key string, valueFN func() interface{}) Op {
+	o.ctx.PutDynamic(key, valueFN)
+	return o
+}
+
+// SetGlobalDynamic is like SetGlobal but uses a function to derive the value
+// at read time.
+func SetGlobalDynamic(key string, valueFN func() interface{}) {
+	cm.PutGlobalDynamic(key, valueFN)
+}
+
+// AsMap mimics the method from context.Manager.
+func AsMap(obj interface{}, includeGlobals bool) context.Map {
+	return cm.AsMap(obj, includeGlobals)
+}
+
+func (o *op) FailIf(err error) error {
+	if err != nil {
+		o.failure.Store(err)
+	}
+	return err
+}
diff --git a/vendor/github.com/getlantern/ops/ops_test.go b/vendor/github.com/getlantern/ops/ops_test.go
new file mode 100644
index 0000000..1c16e73
--- /dev/null
+++ b/vendor/github.com/getlantern/ops/ops_test.go
@@ -0,0 +1,76 @@
+package ops_test
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/getlantern/errors"
+	"github.com/getlantern/ops"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestSuccess(t *testing.T) {
+	var reportedFailure error
+	var reportedCtx map[string]interface{}
+	report := func(failure error, ctx map[string]interface{}) {
+		reportedFailure = failure
+		reportedCtx = ctx
+	}
+
+	ops.RegisterReporter(report)
+	ops.SetGlobal("g", "g1")
+	op := ops.Begin("test_success").Set("a", 1).SetDynamic("b", func() interface{} { return 2 })
+	defer op.End()
+	innerOp := op.Begin("inside")
+	innerOp.FailIf(nil)
+	innerOp.End()
+
+	assert.Nil(t, reportedFailure)
+	expectedCtx := map[string]interface{}{
+		"op":      "inside",
+		"root_op": "test_success",
+		"g":       "g1",
+		"a":       1,
+		"b":       2,
+	}
+	assert.Equal(t, expectedCtx, reportedCtx)
+}
+
+func TestFailure(t *testing.T) {
+	doTestFailure(t, false)
+}
+
+func TestCancel(t *testing.T) {
+	doTestFailure(t, true)
+}
+
+func doTestFailure(t *testing.T, cancel bool) {
+	var reportedFailure error
+	var reportedCtx map[string]interface{}
+	report := func(failure error, ctx map[string]interface{}) {
+		reportedFailure = failure
+		reportedCtx = ctx
+	}
+
+	ops.RegisterReporter(report)
+	op := ops.Begin("test_failure")
+	var wg sync.WaitGroup
+	wg.Add(1)
+	op.Go(func() {
+		op.FailIf(errors.New("I failed").With("errorcontext", 5))
+		wg.Done()
+	})
+	wg.Wait()
+	if cancel {
+		op.Cancel()
+	}
+	op.End()
+
+	if cancel {
+		assert.Nil(t, reportedFailure)
+		assert.Nil(t, reportedCtx)
+	} else {
+		assert.Contains(t, reportedFailure.Error(), "I failed")
+		assert.Equal(t, 5, reportedCtx["errorcontext"])
+	}
+}