diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/.gitignore b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/.gitignore
new file mode 100644
index 0000000..826caa3
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/.gitignore
@@ -0,0 +1,204 @@
+# Created by .ignore support plugin (hsz.mobi)
+### Go template
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
+### Windows template
+# Windows image file caches
+Thumbs.db
+ehthumbs.db
+
+# Folder config file
+Desktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+### Kate template
+# Swap Files #
+.*.kate-swp
+.swp.*
+### SublimeText template
+# cache files for sublime text
+*.tmlanguage.cache
+*.tmPreferences.cache
+*.stTheme.cache
+
+# workspace files are user-specific
+*.sublime-workspace
+
+# project files should be checked into the repository, unless a significant
+# proportion of contributors will probably not be using SublimeText
+# *.sublime-project
+
+# sftp configuration file
+sftp-config.json
+### Linux template
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+### JetBrains template
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and Webstorm
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff:
+.idea
+.idea/tasks.xml
+.idea/dictionaries
+.idea/vcs.xml
+.idea/jsLibraryMappings.xml
+
+# Sensitive or high-churn files:
+.idea/dataSources.ids
+.idea/dataSources.xml
+.idea/dataSources.local.xml
+.idea/sqlDataSources.xml
+.idea/dynamic.xml
+.idea/uiDesigner.xml
+
+# Gradle:
+.idea/gradle.xml
+.idea/libraries
+
+# Mongo Explorer plugin:
+.idea/mongoSettings.xml
+
+## File-based project format:
+*.iws
+
+## Plugin-specific files:
+
+# IntelliJ
+/out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties
+### Xcode template
+# Xcode
+#
+# gitignore contributors: remember to update Global/Xcode.gitignore, Objective-C.gitignore & Swift.gitignore
+
+## Build generated
+build/
+DerivedData/
+
+## Various settings
+*.pbxuser
+!default.pbxuser
+*.mode1v3
+!default.mode1v3
+*.mode2v3
+!default.mode2v3
+*.perspectivev3
+!default.perspectivev3
+xcuserdata/
+
+## Other
+*.moved-aside
+*.xccheckout
+*.xcscmblueprint
+### Eclipse template
+
+.metadata
+bin/
+tmp/
+*.tmp
+*.bak
+*.swp
+*~.nib
+local.properties
+.settings/
+.loadpath
+.recommenders
+
+# Eclipse Core
+.project
+
+# External tool builders
+.externalToolBuilders/
+
+# Locally stored "Eclipse launch configurations"
+*.launch
+
+# PyDev specific (Python IDE for Eclipse)
+*.pydevproject
+
+# CDT-specific (C/C++ Development Tooling)
+.cproject
+
+# JDT-specific (Eclipse Java Development Tools)
+.classpath
+
+# Java annotation processor (APT)
+.factorypath
+
+# PDT-specific (PHP Development Tools)
+.buildpath
+
+# sbteclipse plugin
+.target
+
+# Tern plugin
+.tern-project
+
+# TeXlipse plugin
+.texlipse
+
+# STS (Spring Tool Suite)
+.springBeans
+
+# Code Recommenders
+.recommenders/
+
+
+coverage.txt
+
+#vendor
+vendor/
+
+.envrc
\ No newline at end of file
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/CONTRIBUTING.md b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/CONTRIBUTING.md
new file mode 100644
index 0000000..dd52ab8
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/CONTRIBUTING.md
@@ -0,0 +1,20 @@
+# Contributing
+
+We would love to have people submit pull requests and help make `grpc-ecosystem/go-grpc-middleware` even better 👍.
+
+Fork, then clone the repo:
+
+```bash
+git clone git@github.com:your-username/go-grpc-middleware.git
+```    
+
+Before checking in please run the following:
+
+```bash
+make all
+```
+
+This will `vet`, `fmt`, regenerate documentation and run all tests.
+
+
+Push to your fork and open a pull request.
\ No newline at end of file
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/LICENSE b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/LICENSE
new file mode 100644
index 0000000..b2b0650
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/LICENSE
@@ -0,0 +1,201 @@
+                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
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+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
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+      negligent acts) or agreed to in writing, shall any Contributor be
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+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
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+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
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+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
\ No newline at end of file
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/README.md b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/README.md
new file mode 100644
index 0000000..a12b409
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/README.md
@@ -0,0 +1,93 @@
+# Go gRPC Middleware
+
+[![Travis Build](https://travis-ci.org/grpc-ecosystem/go-grpc-middleware.svg?branch=master)](https://travis-ci.org/grpc-ecosystem/go-grpc-middleware)
+[![Go Report Card](https://goreportcard.com/badge/github.com/grpc-ecosystem/go-grpc-middleware)](https://goreportcard.com/report/github.com/grpc-ecosystem/go-grpc-middleware)
+[![GoDoc](http://img.shields.io/badge/GoDoc-Reference-blue.svg)](https://godoc.org/github.com/grpc-ecosystem/go-grpc-middleware)
+[![SourceGraph](https://sourcegraph.com/github.com/grpc-ecosystem/go-grpc-middleware/-/badge.svg)](https://sourcegraph.com/github.com/grpc-ecosystem/go-grpc-middleware/?badge)
+[![codecov](https://codecov.io/gh/grpc-ecosystem/go-grpc-middleware/branch/master/graph/badge.svg)](https://codecov.io/gh/grpc-ecosystem/go-grpc-middleware)
+[![Apache 2.0 License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](LICENSE)
+[![quality: production](https://img.shields.io/badge/quality-production-orange.svg)](#status)
+[![Slack](https://img.shields.io/badge/slack-%23grpc--middleware-brightgreen)](https://gophers.slack.com/archives/CNJL30P4P)
+
+[gRPC Go](https://github.com/grpc/grpc-go) Middleware: interceptors, helpers, utilities.
+
+## ⚠️  Status
+
+Version [v2](https://github.com/grpc-ecosystem/go-grpc-middleware/tree/v2) is about to be released, with migration guide, which will replace v1. Try v2 and give us feedback! 
+
+Version v1 is currently in deprecation mode, which means only critical and safety bug fixes will be merged.
+
+
+## Middleware
+
+[gRPC Go](https://github.com/grpc/grpc-go) recently acquired support for
+Interceptors, i.e. [middleware](https://medium.com/@matryer/writing-middleware-in-golang-and-how-go-makes-it-so-much-fun-4375c1246e81#.gv7tdlghs)
+that is executed either on the gRPC Server before the request is passed onto the user's application logic, or on the gRPC client around the user call. It is a perfect way to implement
+common patterns: auth, logging, message, validation, retries, or monitoring.
+
+These are generic building blocks that make it easy to build multiple microservices easily.
+The purpose of this repository is to act as a go-to point for such reusable functionality. It contains
+some of them itself, but also will link to useful external repos.
+
+`grpc_middleware` itself provides support for chaining interceptors, here's an example:
+
+```go
+import "github.com/grpc-ecosystem/go-grpc-middleware"
+
+myServer := grpc.NewServer(
+    grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(
+        grpc_ctxtags.StreamServerInterceptor(),
+        grpc_opentracing.StreamServerInterceptor(),
+        grpc_prometheus.StreamServerInterceptor,
+        grpc_zap.StreamServerInterceptor(zapLogger),
+        grpc_auth.StreamServerInterceptor(myAuthFunction),
+        grpc_recovery.StreamServerInterceptor(),
+    )),
+    grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(
+        grpc_ctxtags.UnaryServerInterceptor(),
+        grpc_opentracing.UnaryServerInterceptor(),
+        grpc_prometheus.UnaryServerInterceptor,
+        grpc_zap.UnaryServerInterceptor(zapLogger),
+        grpc_auth.UnaryServerInterceptor(myAuthFunction),
+        grpc_recovery.UnaryServerInterceptor(),
+    )),
+)
+```
+
+## Interceptors
+
+_Please send a PR to add new interceptors or middleware to this list_
+
+#### Auth
+
+- [`grpc_auth`](auth) - a customizable (via `AuthFunc`) piece of auth middleware
+
+#### Logging
+
+- [`grpc_ctxtags`](tags/) - a library that adds a `Tag` map to context, with data populated from request body
+- [`grpc_zap`](logging/zap/) - integration of [zap](https://github.com/uber-go/zap) logging library into gRPC handlers.
+- [`grpc_logrus`](logging/logrus/) - integration of [logrus](https://github.com/sirupsen/logrus) logging library into gRPC handlers.
+- [`grpc_kit`](logging/kit/) - integration of [go-kit/log](https://github.com/go-kit/log) logging library into gRPC handlers.
+- [`grpc_grpc_logsettable`](logging/settable/) - a wrapper around `grpclog.LoggerV2` that allows to replace loggers in runtime (thread-safe).
+
+#### Monitoring
+
+- [`grpc_prometheus`⚡](https://github.com/grpc-ecosystem/go-grpc-prometheus) - Prometheus client-side and server-side monitoring middleware
+- [`otgrpc`⚡](https://github.com/grpc-ecosystem/grpc-opentracing/tree/master/go/otgrpc) - [OpenTracing](http://opentracing.io/) client-side and server-side interceptors
+- [`grpc_opentracing`](tracing/opentracing) - [OpenTracing](http://opentracing.io/) client-side and server-side interceptors with support for streaming and handler-returned tags
+- [`otelgrpc`](https://github.com/open-telemetry/opentelemetry-go-contrib/tree/main/instrumentation/google.golang.org/grpc/otelgrpc) - [OpenTelemetry](https://opentelemetry.io/) client-side and server-side interceptors
+
+#### Client
+
+- [`grpc_retry`](retry/) - a generic gRPC response code retry mechanism, client-side middleware
+
+#### Server
+
+- [`grpc_validator`](validator/) - codegen inbound message validation from `.proto` options
+- [`grpc_recovery`](recovery/) - turn panics into gRPC errors
+- [`ratelimit`](ratelimit/) - grpc rate limiting by your own limiter
+
+
+## License
+
+`go-grpc-middleware` is released under the Apache 2.0 license. See the [LICENSE](LICENSE) file for details.
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go
new file mode 100644
index 0000000..407d933
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/chain.go
@@ -0,0 +1,166 @@
+// Copyright 2016 Michal Witkowski. All Rights Reserved.
+// See LICENSE for licensing terms.
+
+// gRPC Server Interceptor chaining middleware.
+
+package grpc_middleware
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+)
+
+// ChainUnaryServer creates a single interceptor out of a chain of many interceptors.
+//
+// Execution is done in left-to-right order, including passing of context.
+// For example ChainUnaryServer(one, two, three) will execute one before two before three, and three
+// will see context changes of one and two.
+//
+// While this can be useful in some scenarios, it is generally advisable to use google.golang.org/grpc.ChainUnaryInterceptor directly.
+func ChainUnaryServer(interceptors ...grpc.UnaryServerInterceptor) grpc.UnaryServerInterceptor {
+	n := len(interceptors)
+
+	// Dummy interceptor maintained for backward compatibility to avoid returning nil.
+	if n == 0 {
+		return func(ctx context.Context, req interface{}, _ *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+			return handler(ctx, req)
+		}
+	}
+
+	// The degenerate case, just return the single wrapped interceptor directly.
+	if n == 1 {
+		return interceptors[0]
+	}
+
+	// Return a function which satisfies the interceptor interface, and which is
+	// a closure over the given list of interceptors to be chained.
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+		currHandler := handler
+		// Iterate backwards through all interceptors except the first (outermost).
+		// Wrap each one in a function which satisfies the handler interface, but
+		// is also a closure over the `info` and `handler` parameters. Then pass
+		// each pseudo-handler to the next outer interceptor as the handler to be called.
+		for i := n - 1; i > 0; i-- {
+			// Rebind to loop-local vars so they can be closed over.
+			innerHandler, i := currHandler, i
+			currHandler = func(currentCtx context.Context, currentReq interface{}) (interface{}, error) {
+				return interceptors[i](currentCtx, currentReq, info, innerHandler)
+			}
+		}
+		// Finally return the result of calling the outermost interceptor with the
+		// outermost pseudo-handler created above as its handler.
+		return interceptors[0](ctx, req, info, currHandler)
+	}
+}
+
+// ChainStreamServer creates a single interceptor out of a chain of many interceptors.
+//
+// Execution is done in left-to-right order, including passing of context.
+// For example ChainUnaryServer(one, two, three) will execute one before two before three.
+// If you want to pass context between interceptors, use WrapServerStream.
+//
+// While this can be useful in some scenarios, it is generally advisable to use google.golang.org/grpc.ChainStreamInterceptor directly.
+func ChainStreamServer(interceptors ...grpc.StreamServerInterceptor) grpc.StreamServerInterceptor {
+	n := len(interceptors)
+
+	// Dummy interceptor maintained for backward compatibility to avoid returning nil.
+	if n == 0 {
+		return func(srv interface{}, stream grpc.ServerStream, _ *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+			return handler(srv, stream)
+		}
+	}
+
+	if n == 1 {
+		return interceptors[0]
+	}
+
+	return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		currHandler := handler
+		for i := n - 1; i > 0; i-- {
+			innerHandler, i := currHandler, i
+			currHandler = func(currentSrv interface{}, currentStream grpc.ServerStream) error {
+				return interceptors[i](currentSrv, currentStream, info, innerHandler)
+			}
+		}
+		return interceptors[0](srv, stream, info, currHandler)
+	}
+}
+
+// ChainUnaryClient creates a single interceptor out of a chain of many interceptors.
+//
+// Execution is done in left-to-right order, including passing of context.
+// For example ChainUnaryClient(one, two, three) will execute one before two before three.
+func ChainUnaryClient(interceptors ...grpc.UnaryClientInterceptor) grpc.UnaryClientInterceptor {
+	n := len(interceptors)
+
+	// Dummy interceptor maintained for backward compatibility to avoid returning nil.
+	if n == 0 {
+		return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
+			return invoker(ctx, method, req, reply, cc, opts...)
+		}
+	}
+
+	if n == 1 {
+		return interceptors[0]
+	}
+
+	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
+		currInvoker := invoker
+		for i := n - 1; i > 0; i-- {
+			innerInvoker, i := currInvoker, i
+			currInvoker = func(currentCtx context.Context, currentMethod string, currentReq, currentRepl interface{}, currentConn *grpc.ClientConn, currentOpts ...grpc.CallOption) error {
+				return interceptors[i](currentCtx, currentMethod, currentReq, currentRepl, currentConn, innerInvoker, currentOpts...)
+			}
+		}
+		return interceptors[0](ctx, method, req, reply, cc, currInvoker, opts...)
+	}
+}
+
+// ChainStreamClient creates a single interceptor out of a chain of many interceptors.
+//
+// Execution is done in left-to-right order, including passing of context.
+// For example ChainStreamClient(one, two, three) will execute one before two before three.
+func ChainStreamClient(interceptors ...grpc.StreamClientInterceptor) grpc.StreamClientInterceptor {
+	n := len(interceptors)
+
+	// Dummy interceptor maintained for backward compatibility to avoid returning nil.
+	if n == 0 {
+		return func(ctx context.Context, desc *grpc.StreamDesc, cc *grpc.ClientConn, method string, streamer grpc.Streamer, opts ...grpc.CallOption) (grpc.ClientStream, error) {
+			return streamer(ctx, desc, cc, method, opts...)
+		}
+	}
+
+	if n == 1 {
+		return interceptors[0]
+	}
+
+	return func(ctx context.Context, desc *grpc.StreamDesc, cc *grpc.ClientConn, method string, streamer grpc.Streamer, opts ...grpc.CallOption) (grpc.ClientStream, error) {
+		currStreamer := streamer
+		for i := n - 1; i > 0; i-- {
+			innerStreamer, i := currStreamer, i
+			currStreamer = func(currentCtx context.Context, currentDesc *grpc.StreamDesc, currentConn *grpc.ClientConn, currentMethod string, currentOpts ...grpc.CallOption) (grpc.ClientStream, error) {
+				return interceptors[i](currentCtx, currentDesc, currentConn, currentMethod, innerStreamer, currentOpts...)
+			}
+		}
+		return interceptors[0](ctx, desc, cc, method, currStreamer, opts...)
+	}
+}
+
+// Chain creates a single interceptor out of a chain of many interceptors.
+//
+// WithUnaryServerChain is a grpc.Server config option that accepts multiple unary interceptors.
+// Basically syntactic sugar.
+//
+// Deprecated: use google.golang.org/grpc.ChainUnaryInterceptor instead.
+func WithUnaryServerChain(interceptors ...grpc.UnaryServerInterceptor) grpc.ServerOption {
+	return grpc.ChainUnaryInterceptor(interceptors...)
+}
+
+// WithStreamServerChain is a grpc.Server config option that accepts multiple stream interceptors.
+// Basically syntactic sugar.
+//
+// Deprecated: use google.golang.org/grpc.ChainStreamInterceptor instead.
+func WithStreamServerChain(interceptors ...grpc.StreamServerInterceptor) grpc.ServerOption {
+	return grpc.ChainStreamInterceptor(interceptors...)
+}
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/doc.go b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/doc.go
new file mode 100644
index 0000000..718e100
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/doc.go
@@ -0,0 +1,69 @@
+// Copyright 2016 Michal Witkowski. All Rights Reserved.
+// See LICENSE for licensing terms.
+
+/*
+`grpc_middleware` is a collection of gRPC middleware packages: interceptors, helpers and tools.
+
+Middleware
+
+gRPC is a fantastic RPC middleware, which sees a lot of adoption in the Golang world. However, the
+upstream gRPC codebase is relatively bare bones.
+
+This package, and most of its child packages provides commonly needed middleware for gRPC:
+client-side interceptors for retires, server-side interceptors for input validation and auth,
+functions for chaining said interceptors, metadata convenience methods and more.
+
+Chaining
+
+By default, gRPC doesn't allow one to have more than one interceptor either on the client nor on
+the server side. `grpc_middleware` provides convenient chaining methods
+
+Simple way of turning a multiple interceptors into a single interceptor. Here's an example for
+server chaining:
+
+	myServer := grpc.NewServer(
+	    grpc.StreamInterceptor(grpc_middleware.ChainStreamServer(loggingStream, monitoringStream, authStream)),
+	    grpc.UnaryInterceptor(grpc_middleware.ChainUnaryServer(loggingUnary, monitoringUnary, authUnary)),
+	)
+
+These interceptors will be executed from left to right: logging, monitoring and auth.
+
+Here's an example for client side chaining:
+
+	clientConn, err = grpc.Dial(
+	    address,
+	        grpc.WithUnaryInterceptor(grpc_middleware.ChainUnaryClient(monitoringClientUnary, retryUnary)),
+	        grpc.WithStreamInterceptor(grpc_middleware.ChainStreamClient(monitoringClientStream, retryStream)),
+	)
+	client = pb_testproto.NewTestServiceClient(clientConn)
+	resp, err := client.PingEmpty(s.ctx, &myservice.Request{Msg: "hello"})
+
+These interceptors will be executed from left to right: monitoring and then retry logic.
+
+The retry interceptor will call every interceptor that follows it whenever when a retry happens.
+
+Writing Your Own
+
+Implementing your own interceptor is pretty trivial: there are interfaces for that. But the interesting
+bit exposing common data to handlers (and other middleware), similarly to HTTP Middleware design.
+For example, you may want to pass the identity of the caller from the auth interceptor all the way
+to the handling function.
+
+For example, a client side interceptor example for auth looks like:
+
+	func FakeAuthUnaryInterceptor(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+	   newCtx := context.WithValue(ctx, "user_id", "john@example.com")
+	   return handler(newCtx, req)
+	}
+
+Unfortunately, it's not as easy for streaming RPCs. These have the `context.Context` embedded within
+the `grpc.ServerStream` object. To pass values through context, a wrapper (`WrappedServerStream`) is
+needed. For example:
+
+	func FakeAuthStreamingInterceptor(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+	   newStream := grpc_middleware.WrapServerStream(stream)
+	   newStream.WrappedContext = context.WithValue(ctx, "user_id", "john@example.com")
+	   return handler(srv, newStream)
+	}
+*/
+package grpc_middleware
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/makefile b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/makefile
new file mode 100644
index 0000000..b18d2d2
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/makefile
@@ -0,0 +1,17 @@
+SHELL=/bin/bash
+
+GOFILES_NOVENDOR = $(shell go list ./... | grep -v /vendor/)
+
+all: vet fmt test
+
+fmt:
+	go fmt $(GOFILES_NOVENDOR)
+
+vet:
+	# do not check lostcancel, they are intentional.
+	go vet -lostcancel=false $(GOFILES_NOVENDOR)
+
+test: vet
+	./scripts/test_all.sh
+
+.PHONY: all test
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/slack.png b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/slack.png
new file mode 100644
index 0000000..cc8f9a6
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/slack.png
Binary files differ
diff --git a/vendor/github.com/grpc-ecosystem/go-grpc-middleware/wrappers.go b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/wrappers.go
new file mode 100644
index 0000000..05ccfb3
--- /dev/null
+++ b/vendor/github.com/grpc-ecosystem/go-grpc-middleware/wrappers.go
@@ -0,0 +1,30 @@
+// Copyright 2016 Michal Witkowski. All Rights Reserved.
+// See LICENSE for licensing terms.
+
+package grpc_middleware
+
+import (
+	"context"
+
+	"google.golang.org/grpc"
+)
+
+// WrappedServerStream is a thin wrapper around grpc.ServerStream that allows modifying context.
+type WrappedServerStream struct {
+	grpc.ServerStream
+	// WrappedContext is the wrapper's own Context. You can assign it.
+	WrappedContext context.Context
+}
+
+// Context returns the wrapper's WrappedContext, overwriting the nested grpc.ServerStream.Context()
+func (w *WrappedServerStream) Context() context.Context {
+	return w.WrappedContext
+}
+
+// WrapServerStream returns a ServerStream that has the ability to overwrite context.
+func WrapServerStream(stream grpc.ServerStream) *WrappedServerStream {
+	if existing, ok := stream.(*WrappedServerStream); ok {
+		return existing
+	}
+	return &WrappedServerStream{ServerStream: stream, WrappedContext: stream.Context()}
+}