Add Azure Table storage to the list of store providers (#323)

* add Azure Table storage to the list of store providers

* find & replace bug

howto/setup-state-store/README.md

@@ -48,6 +48,7 @@ kubectl apply -f statestore.yaml
 * [Setup Consul](./setup-consul.md)
 * [Setup Memcached](./setup-memcached.md)
 * [Setup Azure CosmosDB](./setup-azure-cosmosdb.md)
+* [Setup Azure Table Storage](./setup-azure-tablestorage.md)
 * [Setup Google Cloud Firestore (Datastore mode)](./setup-firestore.md)
 * [Setup MongoDB](./setup-mongodb.md)
 * [Setup Zookeeper](./setup-zookeeper.md)

howto/setup-state-store/setup-azure-tablestorage.md

@@ -0,0 +1,102 @@
+# Setup Azure Table Storage 
+
+## Creating Azure Storage account
+
+[Follow the instructions](https://docs.microsoft.com/en-us/azure/storage/common/storage-account-create?tabs=azure-portal) from the Azure documentation on how to create an Azure Storage Account. 
+
+If you wish to create a table for Dapr to use, you can do so beforehand. However, Table Storage state provider will create one for you automatically if it doesn't exist.
+
+In order to setup Azure Table Storage as a state store, you will need the following properties:
+
+* **AccountName**: The storage account name. For example: **mystorageaccount**. 
+* **AccountKey**: Primary or secondary storage key.
+* **TableName**: The name of the table to be used for Dapr state. The table will be created for you if it doesn't exist.
+
+## Create a Dapr component
+
+The next step is to create a Dapr component for Azure Table Storage.
+
+Create the following YAML file named `azuretable.yaml`:
+
+```
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: <name>
+spec:
+  type: state.azure.tablestorage
+  metadata:
+  - name: accountName
+    value: <REPLACE-WITH-ACCOUNT-NAME>
+  - name: accountKey
+    value: <REPLACE-WITH-ACCOUNT-KEY>
+  - name: tableName
+    value: <REPLACE-WITH-TABLE-NAME>
+```
+
+The above example uses secrets as plain strings. It is recommended to use a secret store for the secrets as described [here](../../concepts/components/secrets.md).
+
+The following example uses the Kubernetes secret store to retrieve the secrets:
+
+```
+apiVersion: dapr.io/v1alpha1
+kind: Component
+metadata:
+  name: <name>
+spec:
+  type: state.azure.tablestorage
+  metadata:
+  - name: accountName
+    value: <REPLACE-WITH-ACCOUNT-NAME>
+  - name: accountKey
+    secretKeyRef:
+      name: <KUBERNETES-SECRET-NAME>
+      key: <KUBERNETES-SECRET-KEY>
+  - name: tableName
+    value: <REPLACE-WITH-TABLE-NAME>
+```
+
+## Apply the configuration
+
+### In Kubernetes
+
+To apply Azure Table Storage state store to Kubernetes, use the `kubectl` CLI:
+
+```
+kubectl apply -f azuretable.yaml
+```
+
+### Running locally
+
+The Dapr CLI will automatically create a directory named `components` in your current working directory with a Redis component.
+To use Azure Table Storage, replace the redis.yaml file with azuretable.yaml file above.
+
+## Partitioning
+
+The Azure Table Storage state store will use the `key` property provided in the requests to the Dapr API to determine the `row key`. Service Name is used for `partition key`. This provides best performance, as each service type will store state in it's own table partition. 
+
+This state store creates a column called `Value` in the table storage and puts raw state inside it.
+
+For example, the following operation coming from service called `myservice`
+
+```shell
+curl -X POST http://localhost:3500/v1.0/state \
+  -H "Content-Type: application/json"
+  -d '[
+        {
+          "key": "nihilus",
+          "value": "darth"
+        }
+      ]'
+```
+
+will create the following record in a table:
+
+| PartitionKey | RowKey  | Value |
+| ------------ | ------- | ----- |
+| myservice    | nihilus | darth |
+
+## Concurrency
+
+Azure Table Storage state concurrency is achieved by using `ETag`s according to [the official documenation]( https://docs.microsoft.com/en-us/azure/storage/common/storage-concurrency#managing-concurrency-in-table-storage).
+