MM-10702 Moving plugins to use hashicorp go-plugin. (#8978)

* Moving plugins to use hashicorp go-plugin.

* Tweaks from feedback.

5 files changed, 362 insertions, 0 deletions

diff --git a/vendor/github.com/oklog/run/.gitignore b/vendor/github.com/oklog/run/.gitignore
new file mode 100644
index 000000000..a1338d685
--- /dev/null
+++ b/vendor/github.com/oklog/run/.gitignore
@@ -0,0 +1,14 @@
+# Binaries for programs and plugins
+*.exe
+*.dll
+*.so
+*.dylib
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
+.glide/
diff --git a/vendor/github.com/oklog/run/.travis.yml b/vendor/github.com/oklog/run/.travis.yml
new file mode 100644
index 000000000..362bdd41c
--- /dev/null
+++ b/vendor/github.com/oklog/run/.travis.yml
@@ -0,0 +1,12 @@
+language: go
+sudo: false
+go:
+  - 1.x
+  - tip
+install:
+  - go get -v github.com/golang/lint/golint
+  - go build ./...
+script:
+  - go vet ./...
+  - $HOME/gopath/bin/golint .
+  - go test -v -race ./...
diff --git a/vendor/github.com/oklog/run/LICENSE b/vendor/github.com/oklog/run/LICENSE
new file mode 100644
index 000000000..261eeb9e9
--- /dev/null
+++ b/vendor/github.com/oklog/run/LICENSE
@@ -0,0 +1,201 @@
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diff --git a/vendor/github.com/oklog/run/README.md b/vendor/github.com/oklog/run/README.md
new file mode 100644
index 000000000..a7228cd9a
--- /dev/null
+++ b/vendor/github.com/oklog/run/README.md
@@ -0,0 +1,73 @@
+# run
+
+[![GoDoc](https://godoc.org/github.com/oklog/run?status.svg)](https://godoc.org/github.com/oklog/run) 
+[![Build Status](https://travis-ci.org/oklog/run.svg?branch=master)](https://travis-ci.org/oklog/run) 
+[![Go Report Card](https://goreportcard.com/badge/github.com/oklog/run)](https://goreportcard.com/report/github.com/oklog/run)
+[![Apache 2 licensed](https://img.shields.io/badge/license-Apache2-blue.svg)](https://raw.githubusercontent.com/oklog/run/master/LICENSE)
+
+run.Group is a universal mechanism to manage goroutine lifecycles.
+
+Create a zero-value run.Group, and then add actors to it. Actors are defined as
+a pair of functions: an **execute** function, which should run synchronously;
+and an **interrupt** function, which, when invoked, should cause the execute
+function to return. Finally, invoke Run, which blocks until the first actor
+returns. This general-purpose API allows callers to model pretty much any
+runnable task, and achieve well-defined lifecycle semantics for the group.
+
+run.Group was written to manage component lifecycles in func main for 
+[OK Log](https://github.com/oklog/oklog). 
+But it's useful in any circumstance where you need to orchestrate multiple
+goroutines as a unit whole.
+[Click here](https://www.youtube.com/watch?v=LHe1Cb_Ud_M&t=15m45s) to see a
+video of a talk where run.Group is described.
+
+## Examples
+
+### context.Context
+
+```go
+ctx, cancel := context.WithCancel(context.Background())
+g.Add(func() error {
+	return myProcess(ctx, ...)
+}, func(error) {
+	cancel()
+})
+```
+
+### net.Listener
+
+```go
+ln, _ := net.Listen("tcp", ":8080")
+g.Add(func() error {
+	return http.Serve(ln, nil)
+}, func(error) {
+	ln.Close()
+})
+```
+
+### io.ReadCloser
+
+```go
+var conn io.ReadCloser = ...
+g.Add(func() error {
+	s := bufio.NewScanner(conn)
+	for s.Scan() {
+		println(s.Text())
+	}
+	return s.Err()
+}, func(error) {
+	conn.Close()
+})
+```
+
+## Comparisons
+
+Package run is somewhat similar to package 
+[errgroup](https://godoc.org/golang.org/x/sync/errgroup), 
+except it doesn't require actor goroutines to understand context semantics.
+
+It's somewhat similar to package
+[tomb.v1](https://godoc.org/gopkg.in/tomb.v1) or 
+[tomb.v2](https://godoc.org/gopkg.in/tomb.v2),
+except it has a much smaller API surface, delegating e.g. staged shutdown of 
+goroutines to the caller.
diff --git a/vendor/github.com/oklog/run/group.go b/vendor/github.com/oklog/run/group.go
new file mode 100644
index 000000000..832d47dd1
--- /dev/null
+++ b/vendor/github.com/oklog/run/group.go
@@ -0,0 +1,62 @@
+// Package run implements an actor-runner with deterministic teardown. It is
+// somewhat similar to package errgroup, except it does not require actor
+// goroutines to understand context semantics. This makes it suitable for use in
+// more circumstances; for example, goroutines which are handling connections
+// from net.Listeners, or scanning input from a closable io.Reader.
+package run
+
+// Group collects actors (functions) and runs them concurrently.
+// When one actor (function) returns, all actors are interrupted.
+// The zero value of a Group is useful.
+type Group struct {
+	actors []actor
+}
+
+// Add an actor (function) to the group. Each actor must be pre-emptable by an
+// interrupt function. That is, if interrupt is invoked, execute should return.
+// Also, it must be safe to call interrupt even after execute has returned.
+//
+// The first actor (function) to return interrupts all running actors.
+// The error is passed to the interrupt functions, and is returned by Run.
+func (g *Group) Add(execute func() error, interrupt func(error)) {
+	g.actors = append(g.actors, actor{execute, interrupt})
+}
+
+// Run all actors (functions) concurrently.
+// When the first actor returns, all others are interrupted.
+// Run only returns when all actors have exited.
+// Run returns the error returned by the first exiting actor.
+func (g *Group) Run() error {
+	if len(g.actors) == 0 {
+		return nil
+	}
+
+	// Run each actor.
+	errors := make(chan error, len(g.actors))
+	for _, a := range g.actors {
+		go func(a actor) {
+			errors <- a.execute()
+		}(a)
+	}
+
+	// Wait for the first actor to stop.
+	err := <-errors
+
+	// Signal all actors to stop.
+	for _, a := range g.actors {
+		a.interrupt(err)
+	}
+
+	// Wait for all actors to stop.
+	for i := 1; i < cap(errors); i++ {
+		<-errors
+	}
+
+	// Return the original error.
+	return err
+}
+
+type actor struct {
+	execute   func() error
+	interrupt func(error)
+}