Issue #24 add readme for examples/opa-server

Signed-off-by: Phil Hunt <[email protected]>

examples/opa-server/README.md

@@ -0,0 +1,25 @@
+![Hexa](https://hexaorchestration.org/wp-content/themes/hexa/img/logo.svg)
+
+# Example: OPA-Server Integration
+
+This directory shows an example of deploying a HexaOPA server along with an OPA Bundle server (see [docker-compose.yml](docker-compose.yml)).
+
+> [!Note]
+> The opa server and bundle server will automatically look for certificates in the `.certs` sub-directory. If not found,
+> the `hexa-bundle-server` service will auto-generate self-signed keys. This allows the `hexa-opa-server` to set up
+> a TLS connection to the bundle server.
+
+The configuration for the OPA server is defined in [config.yaml](config/config.yaml). This causes the OPA server to load
+bundles from the hexa-bundle-server.
+
+To test with the Hexa CLI tool, use a bundle url of https://127.0.0.1:8889 and reference the `ca_cert.pem` in `.certs`. For example:
+
+```shell
+hexa add opa http myBundle --url="https://hexa-bundle-server:8889" --cafile="./examples/opa-server/.certs/ca-cert.pem"
+```
+
+> [!Tip]
+> You may need to update your /etc/hosts file to define hexa-bundle-server as 127.0.0.1
+
+Finally, you will want to set up an application that queries the hexaOpa server for policy decisions. For more information,
+see the [Hexa Policy-OPA](https://github.com/hexa-org/policy-opa) project.