developer docs for andromeda-akamai-reports app

cmd/andromeda-akamai-reports/README.md

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+<!--
+SPDX-FileCopyrightText: Copyright 2022-2025 SAP SE or an SAP affiliate company and andromeda contributors
+
+SPDX-License-Identifier: Apache-2.0
+-->
+
+# `andromeda-akamai-reports` app
+
+This worker will bind a Prometheus HTTP server to `0.0.0.0:9090` (or the host and port provided by `PROMETHEUS_LISTEN`) and register a collector (`AndromedaAkamaiCollector`) that implements the `prometheus.Collector` interface. Whenever its `/metrics` endpoint is requested, Prometheus invokes `Collect()`, which in turn:
+
+* Iterates over each property using the Akamai GTM API
+* For each property...
+  * Queries the Akamai GTM API for its [traffic report][traffic-report]
+  * Retrieves its respective Keystone project ID from the Andromeda database
+  * Writes the results of the API call to two gauge metrics:
+    * `andromeda_akamai_requests_5m`
+    * `andromeda_akamai_status_5m`
+
+[traffic-report]: <https://techdocs.akamai.com/gtm-reporting/reference/get-traffic-property>
+
+The Akamai metrics will be exposed at <http://localhost:9091/metrics>.
+
+## Manually testing the main flow
+
+Ensure the `akamai.yaml` file points to the desired Akamai domain (`akamai.domain` property).
+
+Ensure that, for each property/domain/server combination that you'd like to test for, there's one respective `datacenter` table record in place. Navigate to the Akamai property details page and copy the the server UUID you'd like to test. Then, create a record in the local Andromeda `datacenter` table by providing some value (a real Keystone project ID is not necessary) for `datacenter.project_id` and  the Akamai property server UUID for `datacenter.id`:
+
+```sql
+INSERT INTO datacenter (id, project_id, provider, admin_state_up) VALUES
+    ("...", "...", "akamai", 1);
+```
+
+On shell 1, start the RPC server.
+
+```sh
+go run cmd/andromemeda-server/main.go \
+    --config-file ./tmp/andromeda.yaml \
+    --config-file ./tmp/akamai.yaml
+```
+
+On Shell 2, start the Akamai Reports app:
+
+```sh
+export PROMETHEUS_LISTEN=0.0.0.0:9091
+go run cmd/andromemeda-akamai-reports/main.go \
+    --config-file ./tmp/andromeda.yaml \
+    --config-file ./tmp/akamai.yaml
+```
+
+In order for Prometheus to invoke the Andromeda Akamai Collector, either browse or curl the `/metrics` endpoint:
+
+```sh
+curl http://0.0.0.0:9091/metrics | grep '_5m'
+```
+
+The output should include data for both `andromeda_akamai_requests_5m` and `andromeda_akamai_status_5m` custom metrics.