opentelemetry: support event_name in logs #10959
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WalkthroughAdds an event_name string field to the OTLP LogRecord protobuf-c structs/descriptors, propagates event name extraction from metadata/message through out_opentelemetry record accessors, packs it in incoming OTLP logs, updates initialization/cleanup, and adds a test case for eventName propagation. Changes
Sequence Diagram(s)sequenceDiagram
autonumber
participant Src as Log Source
participant Out as out_opentelemetry
participant RA as Record Accessors
participant LR as LogRecord (protobuf-c)
participant In as in_opentelemetry (packer)
participant OTLP as OTLP Export
Src->>Out: Emit log (metadata + body)
Out->>RA: Eval ra_log_meta_otlp_event_name
alt found
RA-->>Out: event_name (OTLP meta)
else not found
Out->>RA: Eval ra_event_name_metadata
alt found
RA-->>Out: event_name (custom meta)
else not found
Out->>RA: Eval ra_event_name_message
RA-->>Out: event_name or empty
end
end
Out->>LR: Set LogRecord fields (incl. event_name if present)
Out-->>In: Prepared LogRecord
In->>In: If event_name set -> append "event_name" map entry
In->>OTLP: Pack and send log record
note over In,OTLP: event_name included only when non-null/non-empty
sequenceDiagram
autonumber
participant Cfg as Configuration
participant Out as out_opentelemetry
participant RA as RA Factory
Cfg-->>Out: Load keys (logs_event_name_metadata_key, logs_event_name_message_key)
Out->>RA: Create RA: ra_log_meta_otlp_event_name
Out->>RA: Create RA: ra_event_name_metadata
Out->>RA: Create RA: ra_event_name_message
RA-->>Out: Return RA handles
note right of Out: On teardown, free the three RA resources
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~25 minutes Possibly related PRs
Suggested reviewers
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Pre-merge checks and finishing touches❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
✨ Finishing touches
🧪 Generate unit tests
📜 Recent review detailsConfiguration used: CodeRabbit UI Review profile: CHILL Plan: Pro 📒 Files selected for processing (8)
🚧 Files skipped from review as they are similar to previous changes (3)
🧰 Additional context used🧬 Code graph analysis (2)plugins/out_opentelemetry/opentelemetry_logs.c (3)
plugins/out_opentelemetry/opentelemetry_conf.c (1)
🔇 Additional comments (13)
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🧹 Nitpick comments (3)
plugins/in_opentelemetry/opentelemetry_logs.c (1)
284-290: LGTM! Event name packing follows established pattern.The event_name packing logic correctly checks for null and empty strings, then packs the field into the metadata map using the same pattern as
severity_text. The implementation is consistent with existing code.For a minor optimization (though not critical since it matches existing style), you could cache
strlen(log_record->event_name)to avoid calling it twice:if (log_record->event_name != NULL && strlen(log_record->event_name) > 0) { + size_t event_name_len = strlen(log_record->event_name); flb_mp_map_header_append(&mh); msgpack_pack_str(mp_pck, 10); msgpack_pack_str_body(mp_pck, "event_name", 10); - msgpack_pack_str(mp_pck, strlen(log_record->event_name)); - msgpack_pack_str_body(mp_pck, log_record->event_name, strlen(log_record->event_name)); + msgpack_pack_str(mp_pck, event_name_len); + msgpack_pack_str_body(mp_pck, log_record->event_name, event_name_len); }However, this same pattern exists throughout the file, so consistency may be preferred over this micro-optimization.
tests/internal/data/opentelemetry/test_cases.json (1)
231-249: New test valid_log_with_event_name — correct expectation and schema.Matches OTLP field name (eventName) and maps to log_metadata.otlp.event_name as expected. Consider adding:
- eventName with empty string and ensure packing behavior.
- eventName wrong type (e.g., number/object) to confirm it’s ignored safely.
plugins/out_opentelemetry/opentelemetry_logs.c (1)
652-697: Extract/pack event_name with proper precedence and safety — LGTM.Order: $otlp metadata -> custom metadata RA -> body RA. Uses calloc+strncpy with zeroed buffer; sets NULL when absent to avoid invalid free. Matches severity_text handling.
To reduce duplication with severity_text, consider a tiny helper: copy_string_field_from_ra(ra, src_map, &dst_ptr, &set_flag).
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Review profile: CHILL
Plan: Pro
📒 Files selected for processing (8)
lib/fluent-otel-proto/proto_c/opentelemetry/proto/logs/v1/logs.pb-c.c(4 hunks)lib/fluent-otel-proto/proto_c/opentelemetry/proto/logs/v1/logs.pb-c.h(4 hunks)plugins/in_opentelemetry/opentelemetry_logs.c(1 hunks)plugins/out_opentelemetry/opentelemetry.c(1 hunks)plugins/out_opentelemetry/opentelemetry.h(2 hunks)plugins/out_opentelemetry/opentelemetry_conf.c(3 hunks)plugins/out_opentelemetry/opentelemetry_logs.c(3 hunks)tests/internal/data/opentelemetry/test_cases.json(1 hunks)
🧰 Additional context used
🧬 Code graph analysis (3)
plugins/out_opentelemetry/opentelemetry_logs.c (3)
src/flb_record_accessor.c (1)
flb_ra_get_value_object(803-814)include/fluent-bit/flb_mem.h (2)
flb_calloc(84-96)flb_free(126-128)src/flb_ra_key.c (1)
flb_ra_key_value_destroy(842-851)
plugins/out_opentelemetry/opentelemetry_conf.c (1)
src/flb_record_accessor.c (2)
flb_ra_create(271-358)flb_ra_destroy(232-248)
plugins/in_opentelemetry/opentelemetry_logs.c (1)
src/flb_mp.c (1)
flb_mp_map_header_append(345-349)
🔇 Additional comments (16)
lib/fluent-otel-proto/proto_c/opentelemetry/proto/logs/v1/logs.pb-c.h (3)
261-270: LGTM! Event name field properly documented and positioned.The new
event_namefield is well-documented, follows the OpenTelemetry log data model, and is correctly positioned at the end of the struct to maintain binary compatibility with existing code.
272-274: LGTM! Initializer macro correctly updated.The
OPENTELEMETRY__PROTO__LOGS__V1__LOG_RECORD__INITmacro is properly updated to initialize the newevent_namefield withprotobuf_c_empty_string, consistent with other optional string fields.
13-13: Verify the protobuf-c compiler version downgrade.
The check inlogs.pb-c.hchanged from1005000to1004001, implying the proto was regenerated with an older protoc-c. Ensure this is intentional, won’t break compatibility, and update any build docs or CI configurations accordingly.plugins/out_opentelemetry/opentelemetry.h (2)
139-143: LGTM! Event name fields follow established patterns.The new
logs_event_name_metadata_key,ra_event_name_metadata,logs_event_name_message_key, andra_event_name_messagefields are consistent with the existing dual-source pattern used for other log metadata fields likeseverity_textandspan_id.
208-208: LGTM! OTLP event name accessor properly positioned.The
ra_log_meta_otlp_event_nameaccessor is correctly placed among other OTLP metadata accessors and follows the established naming convention.lib/fluent-otel-proto/proto_c/opentelemetry/proto/logs/v1/logs.pb-c.c (4)
356-356: LGTM! Field descriptor array correctly expanded.The field descriptor array size is properly increased from 10 to 11 fields to accommodate the new
event_namefield. As this is generated code, it correctly reflects the updated protobuf definition.
478-489: LGTM! Event name field descriptor properly structured.The
event_namefield descriptor is correctly configured as a protobuf field number 12, with typePROTOBUF_C_TYPE_STRINGand default valueprotobuf_c_empty_string, following the established pattern for optional string fields.
491-503: LGTM! Field indices correctly updated.The
field_indices_by_namearray is properly updated to includeevent_nameat index 10, maintaining alphabetical ordering of field names.
504-524: LGTM! Message descriptor counts correctly updated.The number range and field count in the message descriptor are properly updated from 10 to 11, reflecting the addition of the
event_namefield.plugins/out_opentelemetry/opentelemetry.c (1)
1099-1108: LGTM! Event name configuration entries properly defined.The new config map entries for
logs_event_name_metadata_keyandlogs_event_name_message_keyare well-structured, use appropriate defaults ($EventName), and follow the established pattern for other log metadata/message keys. The descriptions clearly distinguish between metadata and message body usage.plugins/out_opentelemetry/opentelemetry_conf.c (4)
520-525: Add RA for event_name (metadata) — looks good; confirm config maps exist.Creation mirrors severity_* RAs and logs on failure. Please confirm logs_event_name_metadata_key is present in config_map with sane default, and that null/empty values are handled as “not set”.
526-531: Add RA for event_name (message/body) — consistent with pattern.Matches severity_*_message handling; good to enable body fallback.
621-625: OTLP accessor $otlp['event_name'] — LGTM.Keeps parity with severity_text/number accessors.
815-826: Destructor updated for new RAs — complete.All three event_name accessors are freed; ordering is fine.
plugins/out_opentelemetry/opentelemetry_logs.c (2)
395-395: event_name_set flag added — consistent with existing pattern.Mirrors severity_* flags; keeps free path safe.
725-727: Free event_name alongside severity_text — correct guard.Guard against protobuf_c_empty_string and NULL before free; matches allocator.
Signed-off-by: Pascal Bach <pascal.bach@siemens.com>
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event_namewas stabilitzed in opentelemetry-proto 1.6.0. This change allows to handle the field and pass it along to other opentelemetry consumers.It is implemented analogous to the severity_text.
This includes an updated version of fluent-otel-proto as proposed in fluent/fluent-otel-proto#5
Fixes the remaining problems mentioned in #10143
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