Bug 1942797 - Apply interesting_serverknobs.json when running in automation. r=mkmelin a=pascalc

For non-Firefox builds, automatically apply interesting_serverknobs.json when running tests.

Differential Revision: https://phabricator.services.mozilla.com/D242915

toolkit/components/glean/src/lib.rs

@@ -19,7 +19,8 @@
 
 use firefox_on_glean::{ipc, metrics, pings};
 use nserror::{nsresult, NS_ERROR_FAILURE, NS_OK};
-use nsstring::{nsACString, nsCString};
+use nsstring::{nsACString, nsAString, nsCString};
+use std::fs;
 use thin_vec::ThinVec;
 
 #[macro_use]
@@ -212,3 +213,23 @@ pub extern "C" fn fog_apply_server_knobs_config(config_json: &nsACString) {
 pub extern "C" fn fog_internal_glean_handle_client_inactive() {
     glean::handle_client_inactive();
 }
+
+/// Apply a serverknobs config from the given path.
+#[no_mangle]
+pub extern "C" fn fog_apply_serverknobs(serverknobs_path: &nsAString) -> bool {
+    let config_json = match fs::read_to_string(serverknobs_path.to_string()) {
+        Ok(c) => c,
+        _ => {
+            log::error!(
+                "Boo, couldn't open serverknobs file at {}",
+                serverknobs_path.to_string()
+            );
+            return false;
+        }
+    };
+
+    log::trace!("Loaded serverknobs config. Applying.");
+    glean::glean_apply_server_knobs_config(config_json);
+
+    true
+}

toolkit/components/glean/tests/xpcshell/xpcshell.toml

@@ -5,6 +5,7 @@ head = "head.js"
 ["test_FOGIPCLimit.js"]
 
 ["test_FOGInit.js"]
+skip-if = ["appname == 'thunderbird'"] # Won't run on thunderbird due to a race condition with the generated serverknobs conf.
 
 ["test_FOGPrefs.js"]
 skip-if = ["os == 'android'"] # FOG isn't responsible for monitoring prefs and controlling upload on Android
@@ -26,11 +27,15 @@ skip-if = ["os == 'android'"] # FOG isn't responsible for experiment annotations
 skip-if = ["os == 'android'"] # Server Knobs on mobile will be handled by the specific app
 
 ["test_JOG.js"]
+skip-if = ["appname == 'thunderbird'"] # Won't run on thunderbird due to a race condition with the generated serverknobs conf.
 
 ["test_JOGIPC.js"]
 
 ["test_MillionQ.js"]
-skip-if = ["os == 'android'"] # Android inits its own FOG, so the test won't work.
+skip-if = [
+  "os == 'android'", # Android inits its own FOG, so the test won't work.
+  "appname == 'thunderbird'" # interesting_serverknobs.json isn't applied before init.
+]
 
 ["test_OHTTP.js"]
 skip-if = ["os == 'android'"] # FOG isn't responsible for monitoring prefs and controlling upload on Android

toolkit/components/glean/xpcom/FOG.cpp

@@ -20,7 +20,10 @@
 #include "mozilla/ShutdownPhase.h"
 #include "mozilla/Unused.h"
 #include "nsContentUtils.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
 #include "nsIFOG.h"
+#include "nsIFile.h"
 #include "nsIUserIdleService.h"
 #include "nsServiceManagerUtils.h"
 #include "xpcpublic.h"
@@ -142,8 +145,49 @@ FOG::InitializeFOG(const nsACString& aDataPathOverride,
       },
       ShutdownPhase::AppShutdownConfirmed);
 
-  return glean::impl::fog_init(&aDataPathOverride, &aAppIdOverride,
-                               aDisableInternalPings);
+  nsresult rv = glean::impl::fog_init(&aDataPathOverride, &aAppIdOverride,
+                                      aDisableInternalPings);
+  NS_ENSURE_SUCCESS(rv, rv);
+#ifndef MOZ_BUILD_APP_IS_BROWSER
+  if (xpc::IsInAutomation()) {
+    ApplyInterestingServerKnobs();
+  }
+#endif
+  return rv;
+}
+
+/**
+ * Enable desired metrics, so that tests work even if some metrics were
+ * disabled.
+ * @see JOG::EnsureRuntimeMetricsRegistered()
+ */
+// static
+bool FOG::ApplyInterestingServerKnobs() {
+  // The config we need to process were placed in GreD in
+  // interesting_serverknobs.json.
+  // That file was generated by
+  // toolkit/components/glean/build_scripts/glean_parser_ext/interesting_serverknobs.py
+  nsCOMPtr<nsIFile> knobsFile;
+  if (NS_WARN_IF(NS_FAILED(
+          NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(knobsFile))))) {
+    return false;
+  }
+  if (NS_WARN_IF(
+          NS_FAILED(knobsFile->Append(u"interesting_serverknobs.json"_ns)))) {
+    return false;
+  }
+
+  // We _could_ read the file and apply it here in C++ land,
+  // but let's use Rust because (among other reasons) it's more fun.
+  nsAutoString knobsfileString;
+  if (NS_WARN_IF(NS_FAILED(knobsFile->GetPath(knobsfileString)))) {
+    return false;
+  }
+  if (!glean::impl::fog_apply_serverknobs(&knobsfileString)) {
+    return false;
+  }
+
+  return true;
 }
 
 NS_IMETHODIMP
@@ -372,7 +416,15 @@ NS_IMETHODIMP
 FOG::TestResetFOG(const nsACString& aDataPathOverride,
                   const nsACString& aAppIdOverride) {
   MOZ_ASSERT(XRE_IsParentProcess());
-  return glean::impl::fog_test_reset(&aDataPathOverride, &aAppIdOverride);
+  nsresult rv =
+      glean::impl::fog_test_reset(&aDataPathOverride, &aAppIdOverride);
+  NS_ENSURE_SUCCESS(rv, rv);
+#ifndef MOZ_BUILD_APP_IS_BROWSER
+  if (xpc::IsInAutomation()) {
+    ApplyInterestingServerKnobs();
+  }
+#endif
+  return rv;
 }
 
 NS_IMETHODIMP

toolkit/components/glean/xpcom/FOG.h

@@ -24,6 +24,7 @@ class FOG final : public nsIFOG, public nsIObserver, public nsIMemoryReporter {
 
  private:
   ~FOG() = default;
+  static bool ApplyInterestingServerKnobs();
   void Shutdown();
 };