Add service invocation How To (#43)

* add how to for service discovery

* fix links

* MInor updates

* Update Readme.md

* Changes to doc

concepts/bindings/bindings.md

@@ -10,7 +10,7 @@ Bindings allow for on-demand, event-driven compute scenarios, and dapr bindings
 * Switch between bindings at runtime time
 * Enable portable applications where environment-specific bindings are set-up and no code changes are required
 
-Bindings are developed independently of dapr runtime. You can view and contribute to the bindings [here](https://github.com/actionscore/components-contrib/tree/master/bindings). 
+Bindings are developed independently of Dapr runtime. You can view and contribute to the bindings [here](https://github.com/dapr/components-contrib/tree/master/bindings). 
 
 ## Supported Bindings and Specs
 
@@ -37,24 +37,24 @@ Every binding has its own unique set of properties. Click the name link to see t
 
 ## Input Bindings
 
-Input bindings are used to trigger your app when an event from an external system has occured.
+Input bindings are used to trigger your application when an event from an external resource has occured.
 An optional payload and metadata might be sent with the request.
 
 In order to receive events from an input binding:
 
-1. Define the component YAML that describes the type of bindings and its metadata (connection info, etc.)
+1. Define the component YAML that describes the type of binding and its metadata (connection info, etc.)
 2. Listen on an HTTP endpoint for the incoming event, or use the gRPC proto library to get incoming events.
 
 Read the [How To](../../howto) section to get started with input bindings.
 
 ## Output Bindings
 
-Output bindings allow users to invoke external systems
+Output bindings allow users to invoke external resources
 An optional payload and metadata can be sent with the invocation request.
 
 In order to invoke an output binding:
 
-1. Define the component YAML that describes the type of bindings and its metadata (connection info, etc.)
+1. Define the component YAML that describes the type of binding and its metadata (connection info, etc.)
 2. Use the HTTP endpoint or gRPC method to invoke the binding with an optional payload
 
  Read the [How To](../../howto) section to get started with output bindings.

howto/invoke-and-discover-services/Readme.md

@@ -0,0 +1,99 @@
+# Invoke remote services
+
+In many environments with multiple services that need to communicate with each other, developers often ask themselves the following questions:
+
+* How do I discover and invoke different services?
+* How do I handle retries and transient errors?
+* How do I use distributed tracing correctly to see a call graph?
+
+Dapr allows developers to overcome these challenges by providing an endpoint that acts as a combination of a reverse proxy with built-in service discovery, while leveraging built-in distributed tracing and error handling.
+
+## 1. Choose an ID for your service
+
+Dapr allows you to assign a global, unique ID for your app.<br>
+This ID encapsulates the state for your application, regardless of the number of instances it may have.
+
+### Setup an ID using the Dapr CLI
+
+In Standalone mode, set the `--app-id` flag:
+
+`dapr run --app-id cart --app-port 5000 python app.py`
+
+### Setup an ID using Kubernetes
+
+In Kubernetes, set the `dapr.io/id` annotation on your pod:
+
+<pre>
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: python-app
+  labels:
+    app: python-app
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: python-app
+  template:
+    metadata:
+      labels:
+        app: python-app
+      annotations:
+        dapr.io/enabled: "true"
+        <b>dapr.io/id: "cart"</b>
+        dapr.io/port: "5000"
+...
+</pre>
+
+## Invoke a service in code
+
+Dapr uses a sidecar, decentralized architecture. To invoke an applications using Dapr, you can use the `invoke` endpoint on any Dapr instance in your cluster/environment.
+
+The sidecar programming model encourages each applications to talk to its own instance of Dapr. The Dapr instances discover and communicate with one another.
+
+*Note: The following is a Python example of a cart app. It can be written in any programming language*
+
+```python
+from flask import Flask
+app = Flask(__name__)
+
+@app.route('/add', methods=['POST'])
+def add():
+    return "Added!"
+
+if __name__ == '__main__':
+    app.run()
+```
+
+This Python app exposes an `add()` method via the `/add` endpoint.
+
+### Invoke with curl
+
+```
+curl http://localhost:3500/v1.0/invoke/cart/add -X POST
+```
+
+Since the aoo endpoint is a 'POST' method, we used `-X POST` in the curl command.
+
+To invoke a 'GET' endpoint:
+
+```
+curl http://localhost:3500/v1.0/invoke/cart/add
+```
+
+To invoke a 'DELETE' endpoint:
+
+```
+curl http://localhost:3500/v1.0/invoke/cart/add -X DELETE
+```
+
+Dapr puts any payload return by ther called service in the HTTP response's body.
+
+
+## Overview
+
+The example above showed you how to directly invoke a different service running in our environment, locally or in Kubernetes.
+Dapr outputs metrics and tracing information allowing you to visualize a call graph between services, log errors and optionally log the payload body.
+
+For more information on tracing, visit [this link](../../best-practices/troubleshooting/tracing.md).

howto/trigger-app-with-input-binding/Readme.md

@@ -10,14 +10,14 @@ Dapr bindings allow you to:
 * Replace bindings without changing your code
 * Focus on business logic and not the event resource implementation
 
-For more info on bindings, read [this](../concepts/bindings/bindings.md) link.<br>
+For more info on bindings, read [this](../../concepts/bindings/bindings.md) link.<br>
 For a complete sample showing bindings, visit this [link](<PLACEHOLDER>).
 
 ## 1. Create a binding
 
 An input binding represents an event resource that Dapr uses to read events from and push to your application.
 
-For the purpose of this HowTo, we'll use a Kafka binding. You can find a list of the different binding specs [here](../concepts/bindings/specs).
+For the purpose of this HowTo, we'll use a Kafka binding. You can find a list of the different binding specs [here](../../concepts/bindings/specs).
 
 Create the following YAML file, named binding.yaml, and save this to the /components sub-folder in your application directory: