Add upstreams and targets

This adds upstream and target capabilities to kongfig as requested
in: mybuilder#69

README.md

@@ -322,6 +322,25 @@ consumers:
         ensure: "present"
 ```
 
+### Upstream/Target Schema
+
+[Kong Upstream Load Balancing Reference](https://getkong.org/docs/latest/loadbalancing/)
+
+```yaml
+upstreams:
+  - name: "mockbinUpstream"
+    ensure: "present"
+    targets: 
+      - target: "server1.mockbin:3001"
+        attributes:
+          weight: 50
+      - target: "server2.mockbin:3001"
+        attributes:
+          weight: 50
+    attributes:
+      slots: 100
+```
+
 
 ## Migrating from Kong <=0.9 to >=0.10
 

examples/upstream.example.md

@@ -0,0 +1,149 @@
+upstream example
+------------------
+
+## Config file
+
+```yaml
+upstreams:
+  - name: "mockbinUpstream"
+    ensure: "present"
+    targets: 
+      - target: "server1.mockbin:3001"
+        attributes:
+          weight: 50
+      - target: "server2.mockbin:3001"
+        attributes:
+          weight: 50
+    attributes:
+      slots: 10
+```
+
+Please note that the port is required. If the port is not provided, then Kong will automatically provide a port using it's logic and your config will have a mismatch (see [details here](https://getkong.org/docs/latest/admin-api/#add-target)).
+
+For more information regarding upstreams and targets in Kong, read their [load balancing reference](https://getkong.org/docs/latest/loadbalancing/).
+
+## Using cURL
+
+For illustrative purpose a cURL call would be the following
+
+### create upstream
+
+```bash
+curl -X POST \
+  http://localhost:8001/upstreams \
+  -H 'content-type: application/json' \
+  -d '{
+	"name": "mockbinUpstream",
+	"slots": 10
+}'
+```
+
+```
+HTTP 201 Created
+```
+
+```json
+{
+    "orderlist": [
+        10,
+        4,
+        3,
+        2,
+        6,
+        1,
+        9,
+        5,
+        8,
+        7
+    ],
+    "slots": 10,
+    "id": "4afe745b-0ed9-4e17-82cd-5257f1ad2f1b",
+    "name": "mockbinUpstream",
+    "created_at": 1510849638942
+}
+```
+
+### create first target
+
+```bash
+curl -X POST \
+  http://localhost:8001/upstreams/mockbinUpstream/targets \
+  -H 'content-type: application/json' \
+  -d '{
+	"target": "server1.mockbin:3001",
+	"weight": 50
+}'
+```
+
+```bash
+HTTP 201 Created
+```
+
+```json
+{
+    "target": "server1.mockbin:3001",
+    "id": "8899003f-79c4-48ee-906d-8d2692fd0b98",
+    "weight": 50,
+    "created_at": 1510849726293,
+    "upstream_id": "4afe745b-0ed9-4e17-82cd-5257f1ad2f1b"
+}
+```
+
+### create second target
+
+```bash
+curl -X POST \
+  http://localhost:8001/upstreams/mockbinUpstream/targets \
+  -H 'content-type: application/json' \
+  -d '{
+	"target": "server2.mockbin:3001",
+	"weight": 50
+}'
+```
+
+```bash
+HTTP 201 Created
+```
+
+```json
+{
+    "target": "server2.mockbin:3001",
+    "id": "77149168-25c9-4d04-abb6-9dcb980bd523",
+    "weight": 50,
+    "created_at": 1510850271896,
+    "upstream_id": "4afe745b-0ed9-4e17-82cd-5257f1ad2f1b"
+}
+```
+
+Kong, by design, does not delete targets but keeps adding them. So, if there are two targets with a value of "server1.mockbin:3001", Kong chooses the most recently created one. If the most recent one has a weight of 0 (zero), then the target does not get used. To see the active targets, use the [active targets api](https://getkong.org/docs/latest/admin-api/#list-active-targets):
+
+```bash
+curl -X GET \
+  http://localhost:8001/upstreams/mockbinUpstream/targets/active/
+```
+
+```bash
+HTTP 200 OK
+```
+
+```json
+{
+    "data": [
+        {
+            "weight": 50,
+            "id": "77149168-25c9-4d04-abb6-9dcb980bd523",
+            "target": "server2.mockbin:3001",
+            "created_at": 1510850271896,
+            "upstream_id": "4afe745b-0ed9-4e17-82cd-5257f1ad2f1b"
+        },
+        {
+            "weight": 50,
+            "id": "8899003f-79c4-48ee-906d-8d2692fd0b98",
+            "target": "server1.mockbin:3001",
+            "created_at": 1510849726293,
+            "upstream_id": "4afe745b-0ed9-4e17-82cd-5257f1ad2f1b"
+        }
+    ],
+    "total": 2
+}
+```