OpenTelemetry

Server-side OpenTelemetry instrumentation for distributed tracing and metrics. Requires pip install vgi-rpc[otel].

Usage

from vgi_rpc import RpcServer
from vgi_rpc.otel import OtelConfig, instrument_server

server = RpcServer(MyService, MyServiceImpl())
instrument_server(server)  # uses global TracerProvider / MeterProvider

This creates spans and records metrics for every RPC call:

• Span: includes method name, service name, auth context, duration, error status, and per-call I/O statistics
• Counter: rpc.server.requests — number of RPC requests handled
• Histogram: rpc.server.duration — duration in seconds

Trace context propagates automatically: from contextvars (pipe transport) or W3C headers (HTTP transport).

Span Attributes

Each span carries the following attributes:

Attribute	Type	Description
rpc.system	str	Always "vgi_rpc"
rpc.service	str	Protocol class name
rpc.method	str	Method name
rpc.vgi_rpc.method_type	str	"unary" or "stream"
rpc.vgi_rpc.server_id	str	Server instance identifier
rpc.vgi_rpc.auth.principal	str	Caller principal (when authenticated)
rpc.vgi_rpc.auth.domain	str	Auth scheme (when authenticated)
rpc.vgi_rpc.auth.authenticated	str	"true" or "false"
client.address	str	Client IP address (HTTP only)
user_agent.original	str	User agent string (HTTP only)
rpc.vgi_rpc.input_batches	int	Number of input batches read by the server
rpc.vgi_rpc.output_batches	int	Number of output batches written by the server
rpc.vgi_rpc.input_rows	int	Total rows across all input batches
rpc.vgi_rpc.output_rows	int	Total rows across all output batches
rpc.vgi_rpc.input_bytes	int	Approximate logical bytes across all input batches
rpc.vgi_rpc.output_bytes	int	Approximate logical bytes across all output batches
rpc.vgi_rpc.error_type	str	Exception class name (error spans only)

The I/O statistics attributes (input_batches through output_bytes) are populated from CallStatistics — see CallStatistics for counting semantics.

Note: Byte counts use pa.RecordBatch.get_total_buffer_size() — logical Arrow buffer sizes without IPC framing overhead.

API Reference

OtelConfig

::: vgi_rpc.otel.OtelConfig

instrument_server

::: vgi_rpc.otel.instrument_server