Files
Stephan BehnkeandGitHub a9c9d9921e OTEL setup via environment variables (#5230)
## What changed?
<!-- Describe what has changed in this PR -->

- allow configuring a custom OTEL `service.name` prefix
- allow configuring an OTEL exporter via env vars (following the [OTEL
spec](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/protocol/exporter.md#configuration-options))

**Note that the OTEL exporter from the environment variables will only
be created if there isn't already one from the config.** Creating an
additional one wouldn't make any sense since the env variables would be
applied to both anyways and there would not be any difference between
them.

## Why?
<!-- Tell your future self why have you made these changes -->

Addresses:
- https://github.com/temporalio/temporal/issues/4042
- https://github.com/temporalio/temporal/issues/4041
- our own (increasing) need to enable OpenTelemetry tracing without
touching the Server config (for ad-hoc debugging when working on a SDK,
for example)

## How did you test it?
<!-- How have you verified this change? Tested locally? Added a unit
test? Checked in staging env? -->

I ran an OTEL collector to verify it sends the tracing exports.

These are the env vars I set to make it work:
```go
os.Setenv("OTEL_TRACES_EXPORTER", "oltp")
os.Setenv("OTEL_EXPORTER_OTLP_TRACES_INSECURE", "true")
```

## Potential risks
<!-- Assuming the worst case, what can be broken when deploying this
change to production? -->

I doubt anyone would accidentally have these env variables specified and
turn on OpenTelemetry by accident.

Unless these are specified; no behavior change occurs.

## Is hotfix candidate?
<!-- Is this PR a hotfix candidate or does it require a notification to
be sent to the broader community? (Yes/No) -->

No
2024-02-27 09:30:00 -08:00

102 lines
3.7 KiB
Go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc. All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package telemetry
import (
"errors"
"fmt"
"strings"
"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
otelsdktrace "go.opentelemetry.io/otel/sdk/trace"
"go.temporal.io/server/common/primitives"
)
var (
unsupportedTraceExporter = errors.New("unsupported OTEL exporter")
unsupportedTraceExporterProtocol = errors.New("unsupported OTEL exporter protocol")
)
const (
OtelServiceNameEnvKey = "OTEL_SERVICE_NAME"
OtelTracesExporterTypesEnvKey = "OTEL_TRACES_EXPORTER"
OtelTracesOtlpExporterType = SpanExporterType("otlp")
OtelExporterOtlpTracesProtocolEnvKey = "OTEL_EXPORTER_OTLP_TRACES_PROTOCOL"
OtelExporterOtlpTracesGrcpProtocol = "grpc"
)
type envVarLookup = func(string) (string, bool)
// SpanExportersFromEnv creates OTEL span exporters from environment variables.
func SpanExportersFromEnv(
envVars envVarLookup,
) (map[SpanExporterType]otelsdktrace.SpanExporter, error) {
exporters := map[SpanExporterType]otelsdktrace.SpanExporter{}
exporterTypes, ok := envVars(OtelTracesExporterTypesEnvKey)
if !ok {
return exporters, nil
}
for _, exporterType := range strings.Split(exporterTypes, ",") {
switch SpanExporterType(exporterType) {
case OtelTracesOtlpExporterType:
// only grpc is supported; fail if user requests a different protocol
if protocol, exists := envVars(OtelExporterOtlpTracesProtocolEnvKey); exists {
isSupported := protocol == OtelExporterOtlpTracesGrcpProtocol
if !isSupported {
return nil, fmt.Errorf("%w: %v=%v", unsupportedTraceExporterProtocol, OtelExporterOtlpTracesProtocolEnvKey, protocol)
}
}
// other OTEL configuration env variables are picked up automatically by the exporter itself
exporters[OtelTracesOtlpExporterType] = otlptracegrpc.NewUnstarted()
default:
return nil, fmt.Errorf("%w: %v=%v", unsupportedTraceExporter, OtelTracesExporterTypesEnvKey, exporterType)
}
}
return exporters, nil
}
// ResourceServiceName returns the OpenTelemetry tracing service name for a Temporal service.
func ResourceServiceName(
rsn primitives.ServiceName,
envVars envVarLookup,
) string {
// map "internal-frontend" to "frontend" for the purpose of tracing
if rsn == primitives.InternalFrontendService {
rsn = primitives.FrontendService
}
// allow custom prefix via env vars
serviceNamePrefix := "io.temporal"
if customServicePrefix, found := envVars(OtelServiceNameEnvKey); found {
serviceNamePrefix = customServicePrefix
}
return fmt.Sprintf("%s.%s", serviceNamePrefix, string(rsn))
}