github.com/caddyserver/caddy/v2/modules/caddyhttp/tracing
No package summary is available.
Package
Files: 3. Third party imports: 10. Imports from organisation: 0. Tests: 0. Benchmarks: 0.
Constants
const (
webEngineName = "Caddy"
defaultSpanName = "handler"
nextCallCtxKey caddy.CtxKey = "nextCall"
)Vars
var (
_ caddy.Provisioner = (*Tracing)(nil)
_ caddyhttp.MiddlewareHandler = (*Tracing)(nil)
_ caddyfile.Unmarshaler = (*Tracing)(nil)
)globalTracerProvider stores global tracer provider and is responsible for graceful shutdown when nobody is using it.
var globalTracerProvider = &tracerProvider{}Types
Tracing
Tracing implements an HTTP handler that adds support for distributed tracing, using OpenTelemetry. This module is responsible for the injection and propagation of the trace context. Configure this module via environment variables (see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md). Some values can be overwritten in the configuration file.
type Tracing struct {
// SpanName is a span name. It should follow the naming guidelines here:
// https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#span
SpanName string `json:"span"`
// otel implements opentelemetry related logic.
otel openTelemetryWrapper
logger *zap.Logger
}nextCall
nextCall store the next handler, and the error value return on calling it (if any)
type nextCall struct {
next caddyhttp.Handler
err error
}openTelemetryWrapper
openTelemetryWrapper is responsible for the tracing injection, extraction and propagation.
type openTelemetryWrapper struct {
propagators propagation.TextMapPropagator
handler http.Handler
spanName string
}tracerProvider
This type doesn't have documentation.
type tracerProvider struct {
mu sync.Mutex
tracerProvider *sdktrace.TracerProvider
tracerProvidersCounter int
}Functions
func (*Tracing) Cleanup
Cleanup implements caddy.CleanerUpper and closes any idle connections. It calls Shutdown method for a trace provider https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/sdk.md#shutdown.
func (ot *Tracing) Cleanup() error {
if err := ot.otel.cleanup(ot.logger); err != nil {
return fmt.Errorf("tracerProvider shutdown: %w", err)
}
return nil
}Cognitive complexity: 2, Cyclomatic complexity: 2
func (*Tracing) Provision
Provision implements caddy.Provisioner.
func (ot *Tracing) Provision(ctx caddy.Context) error {
ot.logger = ctx.Logger()
var err error
ot.otel, err = newOpenTelemetryWrapper(ctx, ot.SpanName)
return err
}Cognitive complexity: 0, Cyclomatic complexity: 1
func (*Tracing) ServeHTTP
ServeHTTP implements caddyhttp.MiddlewareHandler.
func (ot *Tracing) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
return ot.otel.ServeHTTP(w, r, next)
}Cognitive complexity: 0, Cyclomatic complexity: 1
func (*Tracing) UnmarshalCaddyfile
UnmarshalCaddyfile sets up the module from Caddyfile tokens. Syntax:
tracing {
[span <span_name>]
}
func (ot *Tracing) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
setParameter := func(d *caddyfile.Dispenser, val *string) error {
if d.NextArg() {
*val = d.Val()
} else {
return d.ArgErr()
}
if d.NextArg() {
return d.ArgErr()
}
return nil
}
// paramsMap is a mapping between "string" parameter from the Caddyfile and its destination within the module
paramsMap := map[string]*string{
"span": &ot.SpanName,
}
d.Next() // consume directive name
if d.NextArg() {
return d.ArgErr()
}
for d.NextBlock(0) {
if dst, ok := paramsMap[d.Val()]; ok {
if err := setParameter(d, dst); err != nil {
return err
}
} else {
return d.ArgErr()
}
}
return nil
}Cognitive complexity: 18, Cyclomatic complexity: 7
func (Tracing) CaddyModule
CaddyModule returns the Caddy module information.
func (Tracing) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "http.handlers.tracing",
New: func() caddy.Module { return new(Tracing) },
}
}Cognitive complexity: 2, Cyclomatic complexity: 1
Private functions
func init
init ()func newOpenTelemetryWrapper
newOpenTelemetryWrapper is responsible for the openTelemetryWrapper initialization using provided configuration.
newOpenTelemetryWrapper (ctx context.Context, spanName string) (openTelemetryWrapper, error)func parseCaddyfile
parseCaddyfile (h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error)func cleanup
cleanup flush all remaining data and shutdown a tracerProvider
cleanup (logger *zap.Logger) errorfunc newResource
newResource creates a resource that describe current handler instance and merge it with a default attributes value.
newResource (webEngineName,webEngineVersion string) (*resource.Resource, error)func serveHTTP
serveHTTP injects a tracing context and call the next handler.
serveHTTP (w http.ResponseWriter, r *http.Request)func spanNameFormatter
spanNameFormatter performs the replacement of placeholders in the span name
spanNameFormatter (operation string, r *http.Request) stringfunc cleanupTracerProvider
cleanupTracerProvider gracefully shutdown a TracerProvider
cleanupTracerProvider (logger *zap.Logger) errorfunc getTracerProvider
getTracerProvider create or return an existing global TracerProvider
getTracerProvider (opts ...sdktrace.TracerProviderOption) *sdktrace.TracerProviderTests
Files: 3. Third party imports: 1. Imports from organisation: 0. Tests: 8. Benchmarks: 0.