Enforce module identity across metric alerts

[Amygos]

Problem

Module-provided metrics and alerts need a consistent module identity before
provider-published alert rules can be safely introduced.

Without module-level isolation, data and alert state belonging to different
module instances can overlap.

Proposed solution

Establish module identity across the metrics and alert flow as the foundation
for provider-published alert rules, while preserving existing behavior.

Implementation and compatibility details are documented in
NethServer/ns8-metrics#79.

[Amygos]

In Testing:

• metrics 1.3.2-dev.1

[Amygos]

Manual QA — module_id label

Preconditions

• Install the testing image as metrics1.
• Run the tests from a root shell on the leader node.
• Inspect generated state with:

runagent -m metrics1
cd ~/.config/state

QA-MID-01 — Add a missing module_id

Publish a target without module_id:

redis-cli -x HSET module/qaapp1/metrics_targets application <<'YAML'
- targets:
  - 127.0.0.1:65531
  labels:
    node: "1"
    environment: qa
YAML

redis-cli PUBLISH module/qaapp1/event/metrics-target-changed '{}'

Expected result:

• The generated target contains module_id: qaapp1.
• The value is derived from the Redis key.
• Existing labels remain unchanged.
• Prometheus discovers the target with module_id="qaapp1".

QA-MID-02 — Replace a conflicting module_id

Publish the following target under module/qaapp1/metrics_targets:

- targets:
  - 127.0.0.1:65531
  labels:
    module_id: qaapp2
    node: "1"

Expected result:

• The generated target contains module_id: qaapp1.
• The supplied qaapp2 value cannot override the Redis-derived identity.
• Metrics logs report module_id='qaapp2' overwritten with 'qaapp1' and identify the Redis key, field, and item position.
• Prometheus remains operational.

QA-MID-03 — Preserve a matching module_id

Publish:

- targets:
  - 127.0.0.1:65531
  labels:
    module_id: qaapp1
    node: "1"

Expected result:

• module_id: qaapp1 remains unchanged.
• No module_id conflict warning is logged.
• Other labels remain unchanged.

QA-MID-04 — Separate different module instances

Publish equivalent targets under:

module/qaapp1/metrics_targets
module/qaapp2/metrics_targets

Expected result:

• The first generated target has module_id: qaapp1.
• The second generated target has module_id: qaapp2.
• Both targets appear independently in Prometheus, even if their addresses and other labels are identical.

QA-MID-05 — Add module_id to every target item

Publish multiple items in one field:

- targets:
  - 127.0.0.1:65531
  labels:
    node: "1"
- targets:
  - 127.0.0.1:65532
  labels:
    node: "2"

Expected result:

• Every item contains the Redis-derived module_id.
• No item is left without module_id.
• Item-specific labels remain unchanged.

QA-MID-06 — Keep built-in node targets module-less

Inspect every generated file matching:

prometheus.d/node_*.yml

Expected result:

• Built-in node targets do not contain module_id.
• Existing node targets remain visible in Prometheus.

Cleanup

redis-cli DEL \
  module/qaapp1/metrics_targets \
  module/qaapp2/metrics_targets

redis-cli PUBLISH module/qaapp1/event/metrics-target-changed '{}'