[8.7](backport #35024) x-pack/filebeat: Add Instance Id to trace filename

CHANGELOG.next.asciidoc

@@ -43,6 +43,7 @@ https://github.com/elastic/beats/compare/v8.2.0\...main[Check the HEAD diff]
 
 *Filebeat*
 [Gcs Input] - Added missing locks for safe concurrency {pull}34914[34914]
+- Add input instance id to request trace filename for httpjson and cel inputs {pull}35037[35037]
 
 *Heartbeat*
 

x-pack/filebeat/docs/inputs/input-cel.asciidoc

@@ -561,6 +561,9 @@ It is possible to log HTTP requests and responses in a CEL program to a local fi
 This option is enabled by setting the `resource.tracer.filename` value. Additional options are available to
 tune log rotation behavior.
 
+To differentiate the trace files generated from different input instances, a placeholder `*` can be added to the filename and will be replaced with the input instance id.
+For Example, `http-request-trace-*.ndjson`.
+
 Enabling this option compromises security and should only be used for debugging.
 
 [float]

x-pack/filebeat/docs/inputs/input-httpjson.asciidoc

@@ -619,6 +619,9 @@ It is possible to log httpjson requests and responses to a local file-system for
 This option is enabled by setting the `request.tracer.filename` value. Additional options are available to
 tune log rotation behavior.
 
+To differentiate the trace files generated from different input instances, a placeholder `*` can be added to the filename and will be replaced with the input instance id.
+For Example, `http-request-trace-*.ndjson`.
+
 Enabling this option compromises security and should only be used for debugging.
 
 [float]

x-pack/filebeat/input/cel/input.go

@@ -110,6 +110,10 @@ func (input) run(env v2.Context, src *source, cursor map[string]interface{}, pub
 
 	ctx := ctxtool.FromCanceller(env.Cancelation)
 
+	if cfg.Resource.Tracer != nil {
+		cfg.Resource.Tracer.Filename = strings.ReplaceAll(cfg.Resource.Tracer.Filename, "*", env.ID)
+	}
+
 	client, err := newClient(ctx, cfg, log)
 	if err != nil {
 		return err

x-pack/filebeat/input/httpjson/input.go

@@ -112,6 +112,10 @@ func run(
 
 	stdCtx := ctxtool.FromCanceller(ctx.Cancelation)
 
+	if config.Request.Tracer != nil {
+		config.Request.Tracer.Filename = strings.ReplaceAll(config.Request.Tracer.Filename, "*", ctx.ID)
+	}
+
 	httpClient, err := newHTTPClient(stdCtx, config, log)
 	if err != nil {
 		return err