Removed OSCache. Using EHCache and Guava instead. (#67)

* Gateway HA implementation

* perf: Utilize EHCache and Guava cache only

* fix: changes after review

* docs: update gateway-ha README.md

* fix: updated after review

* fix: replaced cacheDir with gatewayStateDir

README.md

@@ -1,155 +1,21 @@
 # presto-gateway
-A load balancer / proxy / gateway for presto compute engine.
-
-## Getting Started 
-
-### Build and run
-run `mvn clean install` to build `presto-gateway`
 
-Edit the [config file](gateway/src/main/resources/config.yml.template) and update backend urls 
+A load balancer / proxy / gateway for presto compute engine.
 
-```
-cd gateway/target/
-java -jar gateway-{{VERSION}}-jar-with-dependencies.jar server ../src/presto-gateway/gateway/src/main/resources/config.yml.template
-```
-Now you can access load balanced presto at localhost:8080 port. We will refer to this as `prestogateway.lyft.com`
-
-### Query History UI - check query plans etc.
-PrestoGateway records history of recent queries and displays links to check query details page in respective presto cluster.  
-![prestogateway.lyft.com](docs/assets/prestogateway_query_history.png) 
+## Getting started
 
-### Adhoc vs Scheduled query routing
-In the [config](gateway/src/main/resources/config.yml.template) 
-you can specify if a backend cluster is a part of a routing group. 
-If not specified, cluster will be part of `adhoc` routing group by default.
+Presto Gateway can be deployed as a standalone stateless service or with high availability and external database. For help with setting up a standalone gateway service, please visit [Standalone Gateway](/gateway/#standalone-gateway). For help with setting up a gateway service with high availability, please visit [Gateway-HA](/gateway-ha#gateway-ha).
 
-PrestoGateway router will route any request to `scheduled` group of clusters if request contains header `X-Presto-Routing-Group: scheduled` and there are clusters present with config `routingGroup: scheduled`.
+For further information regarding the design of the gateway, please visit the [Gateway Design Document](/docs/design.md)
 
-If no matching `routingGroup` found, router will route to `adhoc` group of clusters. Please make sure there are clusters under `adhoc` routing group.  
 
 ## Gateway API
 
-### Get all backends behind the gateway
-
-`curl -X GET prestogateway.lyft.com/gateway/backend/all | python -m json.tool`
-```
-[
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8081,
-        "name": "presto1",
-        "proxyTo": "http://presto1.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8083,
-        "name": "presto3",
-        "proxyTo": "http://presto3.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8082,
-        "name": "presto2",
-        "proxyTo": "http://presto2.lyft.com",
-        "routingGroup": "adhoc"
-    }
-]
-```
-
-### Get active backends behind the Gateway
-
-`curl -X GET prestogateway.lyft.com/gateway/backend/active | python -m json.tool`
-```
-[
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8081,
-        "name": "presto1",
-        "proxyTo": "http://presto1.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8082,
-        "name": "presto2",
-        "proxyTo": "http://presto2.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8083,
-        "name": "presto3",
-        "proxyTo": "http://presto3.lyft.com",
-        "routingGroup": "adhoc"
-    }
-]
-```
-### Deactivate a backend 
-
-`curl -X POST prestogateway.lyft.com/gateway/backend/deactivate/presto2`
-
-Verify this by calling get active backends
-```
-curl -X GET prestogateway.lyft.com/gateway/backend/active | python -m json.tool
-[
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8081,
-        "name": "presto1",
-        "proxyTo": "http://presto1.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8083,
-        "name": "presto3",
-        "proxyTo": "http://presto3.lyft.com",
-        "routingGroup": "adhoc"
-    }
-]
-```
-### Activate a backend 
-
-curl -X POST prestogateway.lyft.com/gateway/backend/activate/presto2
+  * [Get all backends behind the gateway](/gateway/#get-all-backends-behind-the-gateway)
+  * [Get active backends behind the Gateway](/gateway/#get-active-backends-behind-the-gateway)
+  * [Deactivate a backend](/gateway/#deactivate-a-backend)
+  * [Activate a backend](/gateway/#activate-a-backend)
 
-Verify this by calling get active backends
-```
-curl -X GET localhost:8090/gateway/backend/active | python -m json.tool
+## Contributing
 
-[
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8081,
-        "name": "presto1",
-        "proxyTo": "http://presto1.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8082,
-        "name": "presto2",
-        "proxyTo": "http://presto2.lyft.com",
-        "routingGroup": "adhoc"
-    },
-    {
-        "active": true,
-        "includeInRouter": true,
-        "localPort": 8083,
-        "name": "presto3",
-        "proxyTo": "http://presto3.lyft.com",
-        "routingGroup": "adhoc"
-    }
-]
-```
+Want to help build Presto Gateway? Check out our [contributing documentation](CONTRIBUTING.md)