3 Commits

Author	SHA1	Message	Date
Miroslav Zagorac	bab0ea7b77	MEDIUM: otel: implemented scope execution and span management ... Implemented the scope execution engine that creates OTel spans, evaluates sample expressions to collect telemetry data, and manages span lifecycle during request and response processing. The scope runner flt_otel_scope_run() was expanded from a stub into a complete implementation that evaluates ACL conditions on the scope, extracts span contexts from HTTP headers when configured, iterates over the scope's span definitions calling flt_otel_scope_run_span() for each, marks and finishes completed spans, and cleans up unused runtime resources. The span runner flt_otel_scope_run_span() creates OTel spans via the tracer with optional parent references (from other spans or extracted contexts), collects telemetry by calling flt_otel_sample_add() for each configured attribute, event, baggage and status entry, then applies the collected data to the span (attributes, events with their own key-value arrays, baggage items, and status code with description) and injects the span context into HTTP headers when configured. The sample evaluation layer converts HAProxy sample expressions into OTel telemetry data. flt_otel_sample_add() evaluates each sample expression against the stream, converts the result via flt_otel_sample_to_value() which preserves native types (booleans as OTELC_VALUE_BOOL, integers as OTELC_VALUE_INT64, all others as strings), and routes the key-value pair to the appropriate collector based on the sample type (attribute, event, baggage, or status). The key-value arrays grow dynamically using the FLT_OTEL_ATTR_INIT_SIZE and FLT_OTEL_ATTR_INC_SIZE constants. Span finishing is handled in two phases: flt_otel_scope_finish_mark() marks spans and contexts for completion using exact name matching or wildcards ("*" for all, "*req*" for request-direction, "*res*" for response-direction), and flt_otel_scope_finish_marked() ends all marked spans with a common monotonic timestamp and destroys their contexts.	2026-04-13 09:23:26 +02:00
Miroslav Zagorac	2e962a5443	MEDIUM: otel: implemented filter callbacks and event dispatcher ... Replaced the stub filter callbacks with full implementations that dispatch OTel events through the scope execution engine, and added the supporting debug, error handling and utility infrastructure. The filter lifecycle callbacks (init, deinit, init_per_thread) now initialize the OpenTelemetry C wrapper library, create the tracer from the instrumentation configuration file, enable HTX stream filtering, and clean up the configuration and memory pools on shutdown. The stream callbacks (attach, stream_start, stream_set_backend, stream_stop, detach, check_timeouts) create the per-stream runtime context on attach with rate-limit based sampling, fire the corresponding OTel events (on-stream-start, on-backend-set, on-stream-stop), manage the idle timeout timer with reschedule logic in detach, and free the runtime context in check_timeouts. The attach callback also registers the required pre and post channel analyzers from the instrumentation configuration. The channel callbacks (start_analyze, pre_analyze, post_analyze, end_analyze) register per-channel analyzers, map analyzer bits to event indices via flt_otel_get_event(), and dispatch the matching events. The end_analyze callback also fires the on-server-unavailable event when response analyzers were configured but never executed. The HTTP callbacks (http_headers, http_end, http_reply, and the debug-only http_payload and http_reset) dispatch their respective request/response events based on the channel direction. The event dispatcher flt_otel_event_run() in event.c iterates over all scopes matching a given event index and calls flt_otel_scope_run() for each, sharing a common monotonic and wall-clock timestamp across all spans within a single event. Error handling is centralized in flt_otel_return_int() and flt_otel_return_void(), which implement the hard-error/soft-error policy: hard errors disable the filter for the stream, soft errors are silently cleared. The new debug.h header provides conditional debug macros (FLT_OTEL_DBG_ARGS, FLT_OTEL_DBG_BUF) and the FLT_OTEL_LOG macro for structured logging through the instrumentation's log server list. The utility layer gained debug-only label functions for channel direction, proxy mode, stream position, filter type, and analyzer bit name lookups.	2026-04-13 09:23:26 +02:00
Miroslav Zagorac	2d56399b0c	MEDIUM: otel: added configuration parser and event model ... Added the full configuration parser that reads the OTel filter's external configuration file and the event model that maps filter events to HAProxy channel analyzers. The event model in event.h defines an X-macro table (FLT_OTEL_EVENT_DEFINES) that maps each filter event to its HAProxy channel analyzer bit, sample fetch direction, and event name. Events cover stream lifecycle (start, stop, backend-set, idle-timeout), client and server sessions, request analyzers (frontend and backend TCP and HTTP inspection, switching rules, sticking rules, RDP cookie), response analyzers (TCP inspection, HTTP response processing), and HTTP headers, end, and reply callbacks. The event names are partially compatible with the SPOE filter. The flt_otel_event_data[] table in event.c is generated from the same X-macro and provides per-event metadata at runtime. The parser in parser.c implements section parsers for the three OTel configuration blocks: otel-instrumentation (tracer identity, log server, config file path, groups, scopes, ACLs, rate-limit, options for disabled/hard-errors/nolognorm, and debug-level), otel-group (group identity and scope list), and otel-scope (scope identity, span definitions with optional root/parent modifiers, attributes, events, baggages, status codes, inject/extract context operations, finish lists, idle-timeout, ACLs, and otel-event binding with optional if/unless ACL conditions). Each section has a post-parse callback that validates the parsed state. The top-level flt_otel_parse_cfg() temporarily registers these section parsers, loads the external configuration file via parse_cfg(), and handles deferred resolution of sample fetch arguments by saving them in conf->smp_args for later resolution in flt_otel_check() when full frontend and backend capabilities are available. The main flt_otel_parse() entry point was extended to parse the filter ID and config file keywords, verify that insecure-fork-wanted is enabled, and wire the parsed configuration into the flt_conf structure. The utility layer gained flt_otel_strtod() and flt_otel_strtoll() for validated string-to-number conversion used by rate-limit and debug-level parsing.	2026-04-13 09:23:26 +02:00