httpjson: Chain request tracer filename sanitization

[kcreddy]

Currently, for each chain step request, we can add request tracer enabled by following config:

- step:
      request.url: {{hostname}}/assets/export/$.export_uuid/chunks/$.chunks_available[:]
      request.method: GET
      request.tracer.filename: "../../logs/httpjson/http-request-trace-*.ndjson"

But, the filename sanitization only occurs on the base/parent tracer as per https://github.com/elastic/beats/blob/main/x-pack/filebeat/input/httpjson/input.go#L122-L125.

Use file sanitization on chain request/response tracer.

[elasticmachine]

Pinging @elastic/security-external-integrations (Team:Security-External Integrations)

[efd6]

Alternative proposal:

diff --git a/x-pack/filebeat/input/httpjson/input.go b/x-pack/filebeat/input/httpjson/input.go
index 928c056d2d..28f5e0c112 100644
--- a/x-pack/filebeat/input/httpjson/input.go
+++ b/x-pack/filebeat/input/httpjson/input.go
@@ -122,6 +122,15 @@ func run(ctx v2.Context, cfg config, pub inputcursor.Publisher, crsr *inputcurso
        if cfg.Request.Tracer != nil {
                id := sanitizeFileName(ctx.ID)
                cfg.Request.Tracer.Filename = strings.ReplaceAll(cfg.Request.Tracer.Filename, "*", id)
+               // Propagate tracer behaviour to all chain children.
+               for i, c := range cfg.Chain {
+                       if c.Step != nil { // Request is validated as required.
+                               cfg.Chain[i].Step.Request.Tracer = cfg.Request.Tracer
+                       }
+                       if c.While != nil { // Request is validated as required.
+                               cfg.Chain[i].While.Request.Tracer = cfg.Request.Tracer
+                       }
+               }
        }
 
        metrics := newInputMetrics(reg)