Improve Readme

README.md

@@ -13,9 +13,82 @@ The main purpose of this software is to bill customers based on their usage of t
 
 Almanach is composed of two parts:
 
-- **Collector**: listen for OpenStack events and store the relevant information in the database.
+- **Collector**: Listen for OpenStack events and store the relevant information in the database.
 - **REST API**: Expose the information collected to external systems.
 
+Requirements
+------------
+
+- OpenStack infrastructure installed (Nova, Cinder...)
+- MongoDB
+- Python 2.7
+
+Database entities
+-----------------
+
+Each entity have at least these properties:
+
+- `entity_id`: Unique id for the entity (UUID)
+- `entity_type`: "instance" or "volume"
+- `project_id`: Tenant unique ID (UUID)
+- `start`: Start date of the resource usage
+- `end`: End date of the resource usage or `null` if the resource still in use by the tenant
+- `name`: Resource name
+
+### Compute Object
+
+```json
+{
+    "entity_id": "UUID",
+    "entity_type": "instance",
+    "project_id": "UUID",
+    "start": ISODate("2014-01-01T06:00:00.000Z"),
+    "end": null,
+    "last_event": ISODate("2014-01-01T06:00:00.000Z"),
+    "flavor": "MyFlavor1",
+    "os": {
+        "distro": "ubuntu",
+        "version": "14.04"
+    },
+    "name": "my-virtual-machine.domain.tld"
+}
+```
+
+### Block Storage Object
+
+```json
+{
+    "entity_id": "UUID",
+    "entity_type": "volume",
+    "project_id": "UUID",
+    "start": ISODate("2014-01-01T06:00:00.000Z"),
+    "end": null,
+    "last_event": ISODate("2014-01-01T06:00:00.000Z"),
+    "volume_type": "MyVolumeType",
+    "size": 50,
+    "name": "my-virtual-machine.domain.tld-volume",
+    "attached_to": "UUID"
+}
+```
+
+List of events handled
+----------------------
+
+Almanach will process those events:
+
+- `compute.instance.create.end`
+- `compute.instance.delete.end`
+- `compute.instance.resize.confirm.end`
+- `compute.instance.rebuild.end`
+- `volume.create.end`
+- `volume.delete.end`
+- `volume.resize.end`
+- `volume.attach.end`
+- `volume.detach.end`
+- `volume.update.end`
+- `volume.exists`
+- `volume_type.create`
+
 License
 -------