feat: Add OTel SDK setup

[christinaexyou]

Description

Supports OpenTelemetry SDK configuration to capture traces, metrics, and logs from the NeMo Guardrails server. Makes the following changes:

• scripts/otel/entrypoint.py - checks that the OTel SDK is enabled before starting the NeMo server
• scripts/otel/otel.py - handles configuration of the OTel SDK

Usage

Ensure that the OTel collector and TempoStack query frontend services are running

Enable tracing and metrics on the config.yml:

models:
...
tracing:
  enabled: true
  adapters:
    - name: OpenTelemetry
  span_format: opentelemetry
  enable_content_capture: false
metrics:
  enabled: true

Start the server via scripts/otel/otel.py:

python scripts/otel/entrypoint.py --config openshift --port 9000 --verbose

Send a request to the NeMo server:

curl -s --max-time 30 ${NEMO_URL} \
  -H "Content-Type: application/json" \
  -d '{"model":"phi3","messages":[{"role":"user","content":"My credit card is 4111-1111-1111-1111 and SSN is 123-45-6789"}]}'

To view metrics, open a new browser window and go to localhost:9000/metrics or $NEMO_URL/metrics:

# HELP python_gc_objects_collected_total Objects collected during gc
# TYPE python_gc_objects_collected_total counter
python_gc_objects_collected_total{generation="0"} 14085.0
python_gc_objects_collected_total{generation="1"} 3726.0
python_gc_objects_collected_total{generation="2"} 150.0
# HELP python_gc_objects_uncollectable_total Uncollectable objects found during GC
# TYPE python_gc_objects_uncollectable_total counter
python_gc_objects_uncollectable_total{generation="0"} 0.0
python_gc_objects_uncollectable_total{generation="1"} 0.0
python_gc_objects_uncollectable_total{generation="2"} 0.0
# HELP python_gc_collections_total Number of times this generation was collected
# TYPE python_gc_collections_total counter
python_gc_collections_total{generation="0"} 484.0
python_gc_collections_total{generation="1"} 44.0
python_gc_collections_total{generation="2"} 3.0
# HELP python_info Python platform information
# TYPE python_info gauge
python_info{implementation="CPython",major="3",minor="13",patchlevel="2",version="3.13.2"} 1.0
# HELP target_info Target metadata
# TYPE target_info gauge
target_info{service_name="nemo-guardrails",telemetry_sdk_language="python",telemetry_sdk_name="opentelemetry",telemetry_sdk_version="1.40.0"} 1.0
# HELP guardrails_requests_total Total guardrails requests handled
# TYPE guardrails_requests_total counter
guardrails_requests_total 1.0
# HELP guardrails_request_duration_seconds End-to-end guardrails request duration
# TYPE guardrails_request_duration_seconds histogram
guardrails_request_duration_seconds_bucket{le="0.005"} 0.0
guardrails_request_duration_seconds_bucket{le="0.01"} 0.0
guardrails_request_duration_seconds_bucket{le="0.025"} 0.0
guardrails_request_duration_seconds_bucket{le="0.05"} 0.0
guardrails_request_duration_seconds_bucket{le="0.075"} 0.0
guardrails_request_duration_seconds_bucket{le="0.1"} 0.0
guardrails_request_duration_seconds_bucket{le="0.25"} 0.0
guardrails_request_duration_seconds_bucket{le="0.5"} 0.0
guardrails_request_duration_seconds_bucket{le="0.75"} 0.0
guardrails_request_duration_seconds_bucket{le="1.0"} 0.0
guardrails_request_duration_seconds_bucket{le="2.5"} 0.0
guardrails_request_duration_seconds_bucket{le="5.0"} 0.0
guardrails_request_duration_seconds_bucket{le="7.5"} 0.0
guardrails_request_duration_seconds_bucket{le="10.0"} 0.0
guardrails_request_duration_seconds_bucket{le="+Inf"} 1.0
guardrails_request_duration_seconds_count 1.0
guardrails_request_duration_seconds_sum 12.145453459001146
# HELP otel_sdk_span_started_total The number of created spans.
# TYPE otel_sdk_span_started_total counter
otel_sdk_span_started_total{otel_span_parent_origin="none",otel_span_sampling_result="RECORD_AND_SAMPLE"} 1.0
otel_sdk_span_started_total{otel_span_parent_origin="local",otel_span_sampling_result="RECORD_AND_SAMPLE"} 4.0
# HELP otel_sdk_span_live The number of created spans with `recording=true` for which the end operation has not been called yet.
# TYPE otel_sdk_span_live gauge
otel_sdk_span_live{otel_span_sampling_result="RECORD_AND_SAMPLE"} 0.0

To view traces, open a new browser window and go to http://localhost:16686:

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[m-misiura]

Before merging, it would be useful to consider the following:

1. currently it is possible to get traces via auto-instrumentation, e.g. see here, what is the advantage of this approach instead of using opentelemetry-instrument auto-instrumentation?
2. there seems to be regression as there is no input validation inside entrypoint.py