inject-declarations

The inject-declarations advice merges declarations produced by a code template into the matched node’s compilation unit.

This is often used to introduce new type definitions or declare foreign functions linked via //go:linkname to avoid creating dependency cycles.

Examples

inject-declarations:
  imports:
    context: context
    ddtrace: github.com/DataDog/dd-trace-go/v2/ddtrace
  links:
  - github.com/DataDog/dd-trace-go/v2/internal/appsec
  - github.com/DataDog/dd-trace-go/v2/internal/appsec/emitter/httpsec
  - github.com/DataDog/dd-trace-go/v2/ddtrace/tracer
  template: |
    //go:linkname __dd_appsec_RASPEnabled github.com/DataDog/dd-trace-go/v2/internal/appsec.RASPEnabled
    func __dd_appsec_RASPEnabled() bool
    
    //go:linkname __dd_httpsec_ProtectRoundTrip github.com/DataDog/dd-trace-go/v2/internal/appsec/emitter/httpsec.ProtectRoundTrip
    func __dd_httpsec_ProtectRoundTrip(context.Context, string) error
    
    //go:linkname __dd_tracer_SpanType github.com/DataDog/dd-trace-go/v2/ddtrace/tracer.SpanType
    func __dd_tracer_SpanType(string) ddtrace.StartSpanOption
    
    //go:linkname __dd_tracer_ResourceName github.com/DataDog/dd-trace-go/v2/ddtrace/tracer.ResourceName
    func __dd_tracer_ResourceName(string) ddtrace.StartSpanOption
    
    //go:linkname __dd_tracer_Tag github.com/DataDog/dd-trace-go/v2/ddtrace/tracer.Tag
    func __dd_tracer_Tag(string, any) ddtrace.StartSpanOption
    
    //go:linkname __dd_tracer_StartSpanFromContext github.com/DataDog/dd-trace-go/v2/ddtrace/tracer.StartSpanFromContext
    func __dd_tracer_StartSpanFromContext(context.Context, string, ...ddtrace.StartSpanOption) (ddtrace.Span, context.Context)
    
    //go:linkname __dd_tracer_WithError github.com/DataDog/dd-trace-go/v2/ddtrace/tracer.WithError
    func __dd_tracer_WithError(error) ddtrace.FinishOption
    
    //go:linkname __dd_tracer_Inject github.com/DataDog/dd-trace-go/v2/ddtrace/tracer.Inject
    func __dd_tracer_Inject(ddtrace.SpanContext, any) error
    
    type __dd_tracer_HTTPHeadersCarrier Header
    func (c __dd_tracer_HTTPHeadersCarrier) Set(key, val string) {
      Header(c).Set(key, val)
    }

inject-declarations:
  imports:
    ddtrace: github.com/DataDog/dd-trace-go/v2/ddtrace
    http: net/http
    internal: github.com/DataDog/dd-trace-go/v2/internal
    telemetry: github.com/DataDog/dd-trace-go/v2/internal/telemetry
    tracer: github.com/DataDog/dd-trace-go/v2/ddtrace/tracer
  template: |-
    type ddRouterConfig struct {
      ignoreRequest func(*http.Request) bool
      headerTags    *internal.LockMap
      resourceNamer func(*Router, *http.Request) string
      serviceName   string
      spanOpts      []ddtrace.StartSpanOption
    }
    
    func ddDefaultResourceNamer(router *Router, req *http.Request) string {
      var (
        match RouteMatch
        route = "unknown"
      )
      if router.Match(req, &match) && match.Route != nil {
        if r, err := match.Route.GetPathTemplate(); err == nil {
          route = r
        }
      }
      return fmt.Sprintf("%s %s", req.Method, route)
    }
    
    func init() {
      telemetry.LoadIntegration("gorilla/mux")
      tracer.MarkIntegrationImported("github.com/gorilla/mux")
    }

assign-value prepend-statements