feat: complete OTEL tracing across all services with pipeline bridge and docs

Extends tracing to every remaining module: all 23 API route handlers,
correlation engine, sniffer (fingerprint/p0f/syslog), prober (jarm/hassh/tcpfp),
profiler behavioral analysis, logging subsystem, engine, and mutator.

Bridges the ingester→SSE trace gap by persisting trace_id/span_id columns on
the logs table and creating OTEL span links in the SSE endpoint. Adds log-trace
correlation via _TraceContextFilter injecting otel_trace_id into Python LogRecords.

Includes development/docs/TRACING.md with full span reference (76 spans),
pipeline propagation architecture, quick start guide, and troubleshooting.

decnet/web/router/attackers/api_get_attacker_commands.py

@@ -2,6 +2,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, HTTPException, Query
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 
 router = APIRouter()
@@ -15,6 +16,7 @@ router = APIRouter()
         404: {"description": "Attacker not found"},
     },
 )
+@_traced("api.get_attacker_commands")
 async def get_attacker_commands(
     uuid: str,
     limit: int = Query(50, ge=1, le=200),

decnet/web/router/attackers/api_get_attacker_detail.py

@@ -2,6 +2,7 @@ from typing import Any
 
 from fastapi import APIRouter, Depends, HTTPException
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 
 router = APIRouter()
@@ -15,6 +16,7 @@ router = APIRouter()
         404: {"description": "Attacker not found"},
     },
 )
+@_traced("api.get_attacker_detail")
 async def get_attacker_detail(
     uuid: str,
     user: dict = Depends(require_viewer),

decnet/web/router/attackers/api_get_attackers.py

@@ -2,6 +2,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, Query
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import AttackersResponse
 
@@ -17,6 +18,7 @@ router = APIRouter()
         422: {"description": "Validation error"},
     },
 )
+@_traced("api.get_attackers")
 async def get_attackers(
     limit: int = Query(50, ge=1, le=1000),
     offset: int = Query(0, ge=0, le=2147483647),

decnet/web/router/auth/api_change_pass.py

@@ -2,6 +2,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, HTTPException, status
 
+from decnet.telemetry import traced as _traced
 from decnet.web.auth import get_password_hash, verify_password
 from decnet.web.dependencies import get_current_user_unchecked, repo
 from decnet.web.db.models import ChangePasswordRequest
@@ -18,6 +19,7 @@ router = APIRouter()
         422: {"description": "Validation error"}
     },
 )
+@_traced("api.change_password")
 async def change_password(request: ChangePasswordRequest, current_user: str = Depends(get_current_user_unchecked)) -> dict[str, str]:
     _user: Optional[dict[str, Any]] = await repo.get_user_by_uuid(current_user)
     if not _user or not verify_password(request.old_password, _user["password_hash"]):

decnet/web/router/auth/api_login.py

@@ -3,6 +3,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, HTTPException, status
 
+from decnet.telemetry import traced as _traced
 from decnet.web.auth import (
     ACCESS_TOKEN_EXPIRE_MINUTES,
     create_access_token,
@@ -24,6 +25,7 @@ router = APIRouter()
         422: {"description": "Validation error"}
     },
 )
+@_traced("api.login")
 async def login(request: LoginRequest) -> dict[str, Any]:
     _user: Optional[dict[str, Any]] = await repo.get_user_by_username(request.username)
     if not _user or not verify_password(request.password, _user["password_hash"]):

decnet/web/router/bounty/api_get_bounties.py

@@ -2,6 +2,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, Query
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import BountyResponse
 
@@ -10,6 +11,7 @@ router = APIRouter()
 
 @router.get("/bounty", response_model=BountyResponse, tags=["Bounty Vault"],
     responses={401: {"description": "Could not validate credentials"}, 422: {"description": "Validation error"}},)
+@_traced("api.get_bounties")
 async def get_bounties(
     limit: int = Query(50, ge=1, le=1000),
     offset: int = Query(0, ge=0, le=2147483647),

decnet/web/router/config/api_get_config.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter, Depends
 
 from decnet.env import DECNET_DEVELOPER
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import UserResponse
 
@@ -17,6 +18,7 @@ _DEFAULT_MUTATION_INTERVAL = "30m"
         401: {"description": "Could not validate credentials"},
     },
 )
+@_traced("api.get_config")
 async def api_get_config(user: dict = Depends(require_viewer)) -> dict:
     limits_state = await repo.get_state("config_limits")
     globals_state = await repo.get_state("config_globals")

decnet/web/router/config/api_manage_users.py

@@ -2,6 +2,7 @@ import uuid as _uuid
 
 from fastapi import APIRouter, Depends, HTTPException
 
+from decnet.telemetry import traced as _traced
 from decnet.web.auth import get_password_hash
 from decnet.web.dependencies import require_admin, repo
 from decnet.web.db.models import (
@@ -24,6 +25,7 @@ router = APIRouter()
         422: {"description": "Validation error"},
     },
 )
+@_traced("api.create_user")
 async def api_create_user(
     req: CreateUserRequest,
     admin: dict = Depends(require_admin),
@@ -57,6 +59,7 @@ async def api_create_user(
         404: {"description": "User not found"},
     },
 )
+@_traced("api.delete_user")
 async def api_delete_user(
     user_uuid: str,
     admin: dict = Depends(require_admin),
@@ -80,6 +83,7 @@ async def api_delete_user(
         422: {"description": "Validation error"},
     },
 )
+@_traced("api.update_user_role")
 async def api_update_user_role(
     user_uuid: str,
     req: UpdateUserRoleRequest,
@@ -106,6 +110,7 @@ async def api_update_user_role(
         422: {"description": "Validation error"},
     },
 )
+@_traced("api.reset_user_password")
 async def api_reset_user_password(
     user_uuid: str,
     req: ResetUserPasswordRequest,

decnet/web/router/config/api_reinit.py

@@ -1,6 +1,7 @@
 from fastapi import APIRouter, Depends, HTTPException
 
 from decnet.env import DECNET_DEVELOPER
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_admin, repo
 
 router = APIRouter()
@@ -14,6 +15,7 @@ router = APIRouter()
         403: {"description": "Admin access required or developer mode not enabled"},
     },
 )
+@_traced("api.reinit")
 async def api_reinit(admin: dict = Depends(require_admin)) -> dict:
     if not DECNET_DEVELOPER:
         raise HTTPException(status_code=403, detail="Developer mode is not enabled")

decnet/web/router/config/api_update_config.py

@@ -1,5 +1,6 @@
 from fastapi import APIRouter, Depends
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_admin, repo
 from decnet.web.db.models import DeploymentLimitRequest, GlobalMutationIntervalRequest
 
@@ -15,6 +16,7 @@ router = APIRouter()
         422: {"description": "Validation error"},
     },
 )
+@_traced("api.update_deployment_limit")
 async def api_update_deployment_limit(
     req: DeploymentLimitRequest,
     admin: dict = Depends(require_admin),
@@ -32,6 +34,7 @@ async def api_update_deployment_limit(
         422: {"description": "Validation error"},
     },
 )
+@_traced("api.update_global_mutation_interval")
 async def api_update_global_mutation_interval(
     req: GlobalMutationIntervalRequest,
     admin: dict = Depends(require_admin),

decnet/web/router/fleet/api_deploy_deckies.py

@@ -3,6 +3,7 @@ import os
 from fastapi import APIRouter, Depends, HTTPException
 
 from decnet.logging import get_logger
+from decnet.telemetry import traced as _traced
 from decnet.config import DEFAULT_MUTATE_INTERVAL, DecnetConfig, _ROOT
 from decnet.engine import deploy as _deploy
 from decnet.ini_loader import load_ini_from_string
@@ -27,6 +28,7 @@ router = APIRouter()
         500: {"description": "Deployment failed"}
     }
 )
+@_traced("api.deploy_deckies")
 async def api_deploy_deckies(req: DeployIniRequest, admin: dict = Depends(require_admin)) -> dict[str, str]:
     from decnet.fleet import build_deckies_from_ini
 

decnet/web/router/fleet/api_get_deckies.py

@@ -2,6 +2,7 @@ from typing import Any
 
 from fastapi import APIRouter, Depends
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 
 router = APIRouter()
@@ -9,5 +10,6 @@ router = APIRouter()
 
 @router.get("/deckies", tags=["Fleet Management"],
     responses={401: {"description": "Could not validate credentials"}, 422: {"description": "Validation error"}},)
+@_traced("api.get_deckies")
 async def get_deckies(user: dict = Depends(require_viewer)) -> list[dict[str, Any]]:
     return await repo.get_deckies()

decnet/web/router/fleet/api_mutate_decky.py

@@ -1,6 +1,7 @@
 import os
 from fastapi import APIRouter, Depends, HTTPException, Path
 
+from decnet.telemetry import traced as _traced
 from decnet.mutator import mutate_decky
 from decnet.web.dependencies import require_admin, repo
 
@@ -12,6 +13,7 @@ router = APIRouter()
     tags=["Fleet Management"],
     responses={401: {"description": "Could not validate credentials"}, 403: {"description": "Insufficient permissions"}, 404: {"description": "Decky not found"}}
 )
+@_traced("api.mutate_decky")
 async def api_mutate_decky(
     decky_name: str = Path(..., pattern=r"^[a-z0-9\-]{1,64}$"),
     admin: dict = Depends(require_admin),

decnet/web/router/fleet/api_mutate_interval.py

@@ -1,5 +1,6 @@
 from fastapi import APIRouter, Depends, HTTPException
 
+from decnet.telemetry import traced as _traced
 from decnet.config import DecnetConfig
 from decnet.web.dependencies import require_admin, repo
 from decnet.web.db.models import MutateIntervalRequest
@@ -24,6 +25,7 @@ def _parse_duration(s: str) -> int:
         422: {"description": "Validation error"}
     },
 )
+@_traced("api.update_mutate_interval")
 async def api_update_mutate_interval(decky_name: str, req: MutateIntervalRequest, admin: dict = Depends(require_admin)) -> dict[str, str]:
     state_dict = await repo.get_state("deployment")
     if not state_dict:

decnet/web/router/health/api_get_health.py

@@ -3,6 +3,7 @@ from typing import Any
 from fastapi import APIRouter, Depends
 from fastapi.responses import JSONResponse
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import HealthResponse, ComponentHealth
 
@@ -20,6 +21,7 @@ _OPTIONAL_SERVICES = {"sniffer_worker"}
         503: {"model": HealthResponse, "description": "System unhealthy"},
     },
 )
+@_traced("api.get_health")
 async def get_health(user: dict = Depends(require_viewer)) -> Any:
     components: dict[str, ComponentHealth] = {}
 

decnet/web/router/logs/api_get_histogram.py

@@ -2,6 +2,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, Query
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 
 router = APIRouter()
@@ -9,6 +10,7 @@ router = APIRouter()
 
 @router.get("/logs/histogram", tags=["Logs"],
     responses={401: {"description": "Could not validate credentials"}, 422: {"description": "Validation error"}},)
+@_traced("api.get_logs_histogram")
 async def get_logs_histogram(
     search: Optional[str] = None,
     start_time: Optional[str] = Query(None),

decnet/web/router/logs/api_get_logs.py

@@ -2,6 +2,7 @@ from typing import Any, Optional
 
 from fastapi import APIRouter, Depends, Query
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import LogsResponse
 
@@ -10,6 +11,7 @@ router = APIRouter()
 
 @router.get("/logs", response_model=LogsResponse, tags=["Logs"],
     responses={401: {"description": "Could not validate credentials"}, 422: {"description": "Validation error"}})
+@_traced("api.get_logs")
 async def get_logs(
     limit: int = Query(50, ge=1, le=1000),
     offset: int = Query(0, ge=0, le=2147483647),

decnet/web/router/stats/api_get_stats.py

@@ -2,6 +2,7 @@ from typing import Any
 
 from fastapi import APIRouter, Depends
 
+from decnet.telemetry import traced as _traced
 from decnet.web.dependencies import require_viewer, repo
 from decnet.web.db.models import StatsResponse
 
@@ -10,5 +11,6 @@ router = APIRouter()
 
 @router.get("/stats", response_model=StatsResponse, tags=["Observability"],
     responses={401: {"description": "Could not validate credentials"}, 422: {"description": "Validation error"}},)
+@_traced("api.get_stats")
 async def get_stats(user: dict = Depends(require_viewer)) -> dict[str, Any]:
     return await repo.get_stats_summary()

decnet/web/router/stream/api_stream_events.py

@@ -7,6 +7,7 @@ from fastapi.responses import StreamingResponse
 
 from decnet.env import DECNET_DEVELOPER
 from decnet.logging import get_logger
+from decnet.telemetry import traced as _traced, get_tracer as _get_tracer
 from decnet.web.dependencies import require_stream_viewer, repo
 
 log = get_logger("api")
@@ -14,6 +15,34 @@ log = get_logger("api")
 router = APIRouter()
 
 
+def _build_trace_links(logs: list[dict]) -> list:
+    """Build OTEL span links from persisted trace_id/span_id in log rows.
+
+    Returns an empty list when tracing is disabled (no OTEL imports).
+    """
+    try:
+        from opentelemetry.trace import Link, SpanContext, TraceFlags
+    except ImportError:
+        return []
+    links: list[Link] = []
+    for entry in logs:
+        tid = entry.get("trace_id")
+        sid = entry.get("span_id")
+        if not tid or not sid or tid == "0":
+            continue
+        try:
+            ctx = SpanContext(
+                trace_id=int(tid, 16),
+                span_id=int(sid, 16),
+                is_remote=True,
+                trace_flags=TraceFlags(TraceFlags.SAMPLED),
+            )
+            links.append(Link(ctx))
+        except (ValueError, TypeError):
+            continue
+    return links
+
+
 @router.get("/stream", tags=["Observability"],
     responses={
         200: {
@@ -24,6 +53,7 @@ router = APIRouter()
         422: {"description": "Validation error"}
     },
 )
+@_traced("api.stream_events")
 async def stream_events(
     request: Request,
     last_event_id: int = Query(0, alias="lastEventId"),
@@ -75,7 +105,15 @@ async def stream_events(
                 )
                 if new_logs:
                     last_id = max(entry["id"] for entry in new_logs)
-                    yield f"event: message\ndata: {json.dumps({'type': 'logs', 'data': new_logs})}\n\n"
+                    # Create a span linking back to the ingestion traces
+                    # stored in each log row, closing the pipeline gap.
+                    _links = _build_trace_links(new_logs)
+                    _tracer = _get_tracer("sse")
+                    with _tracer.start_as_current_span(
+                        "sse.emit_logs", links=_links,
+                        attributes={"log_count": len(new_logs)},
+                    ):
+                        yield f"event: message\ndata: {json.dumps({'type': 'logs', 'data': new_logs})}\n\n"
                     loops_since_stats = stats_interval_sec
 
                 if loops_since_stats >= stats_interval_sec: