Align otel tracer caching implementation

R/otel.R

@@ -1,51 +1,50 @@
 otel_tracer_name = 'org.yihui.knitr'
-otel_tracer = NULL
-otel_is_tracing = FALSE
 
 # generic otel helpers:
 
-# - without specifying `scope`, the span ends when this function returns;
-#   to make this a local span (last as long as the function it is called from),
-#   specify `scope = environment()`
-# - arguments remain unevaluated on early return
-otel_active_span = function(
-  name,
-  label,
-  attributes = list(),
-  scope = environment()
-) {
-  otel_is_tracing || return()
-  otel::start_local_active_span(
-    name = sprintf('%s %s', name, label),
-    attributes = otel::as_attributes(attributes),
-    tracer = otel_tracer,
-    activation_scope = scope
-  )
-}
+otel_cache_tracer = NULL
+otel_active_span = NULL
 
-otel_cache_tracer = function() {
-  requireNamespace('otel', quietly = TRUE) || return()
-  otel_tracer <<- otel::get_tracer(otel_tracer_name)
-  otel_is_tracing <<- tracer_enabled(otel_tracer)
-}
+local({
+  otel_tracer = NULL
+  otel_is_tracing = FALSE
+
+  otel_cache_tracer <<- function() {
+    requireNamespace('otel', quietly = TRUE) || return()
+    otel_tracer <<- otel::get_tracer(otel_tracer_name)
+    otel_is_tracing <<- tracer_enabled(otel_tracer)
+  }
+
+  # - without specifying `scope`, the span ends when this function returns;
+  #   to make this a local span (last as long as the function it is called from),
+  #   specify `scope = environment()`
+  # - arguments remain unevaluated on early return
+  otel_active_span <<- function(
+    name,
+    label,
+    attributes = list(),
+    scope = environment()
+  ) {
+    otel_is_tracing || return()
+    otel::start_local_active_span(
+      name = sprintf('%s %s', name, label),
+      attributes = otel::as_attributes(attributes),
+      tracer = otel_tracer,
+      activation_scope = scope
+    )
+  }
+})
 
 tracer_enabled = function(tracer) {
   .subset2(tracer, 'is_enabled')()
 }
 
-otel_refresh_tracer = function(pkgname) {
-  requireNamespace('otel', quietly = TRUE) || return()
-  tracer = otel::get_tracer()
-  modify_binding(
-    getNamespace(pkgname),
-    list(otel_tracer = tracer, otel_is_tracing = tracer_enabled(tracer))
-  )
-}
-
-modify_binding = function(env, lst) {
-  lapply(names(lst), unlockBinding, env)
-  list2env(lst, envir = env)
-  lapply(names(lst), lockBinding, env)
+with_otel_record = function(expr) {
+  on.exit(otel_cache_tracer())
+  otelsdk::with_otel_record({
+    otel_cache_tracer()
+    expr
+  })
 }
 
 # knitr-specific helpers:

tests/testit/test-otel.R

@@ -2,10 +2,7 @@ library(testit)
 
 if (requireNamespace('otelsdk', quietly = TRUE)) {
 
-  record = otelsdk::with_otel_record({
-    # refresh tracer within the `with_otel_record()` scope
-    otel_refresh_tracer('knitr')
-
+  record = with_otel_record({
     knit(
       text = c('<<tidy=FALSE, eval=1:2, echo=FALSE, results="asis">>=', '1', '1+', '1', '1', '@'),
       quiet = TRUE
@@ -32,9 +29,7 @@ if (requireNamespace('otelsdk', quietly = TRUE)) {
     (traces[[3L]]$attributes$knitr.output %==% '')
   })
 
-  record = otelsdk::with_otel_record({
-    otel_refresh_tracer('knitr')
-
+  record = with_otel_record({
     local({
       env = new.env()
       env$y = 1:3
@@ -64,7 +59,4 @@ if (requireNamespace('otelsdk', quietly = TRUE)) {
     (traces[[3L]]$attributes$knitr.output %==% 'knit-envir.md')
   })
 
-  # reset tracer after tests
-  otel_refresh_tracer('knitr')
-
 }