Domain Reliability: Histogram net error codes from uploads

components/domain_reliability/uploader.cc

Index: components/domain_reliability/uploader.cc
diff --git a/components/domain_reliability/uploader.cc b/components/domain_reliability/uploader.cc
index 10084569a302b26948e6ad2656d9508a83e029ed..d2388fe91224ca21d0110aafc426780211d621f0 100644
--- a/components/domain_reliability/uploader.cc
+++ b/components/domain_reliability/uploader.cc
@@ -11,6 +11,7 @@
 #include "base/stl_util.h"
 #include "base/supports_user_data.h"
 #include "net/base/load_flags.h"
+#include "net/base/net_errors.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_fetcher_delegate.h"
 #include "net/url_request/url_request_context_getter.h"
@@ -93,13 +94,25 @@ class DomainReliabilityUploaderImpl
     UploadCallbackMap::iterator callback_it = upload_callbacks_.find(fetcher);
     DCHECK(callback_it != upload_callbacks_.end());
 
-    VLOG(1) << "Upload finished with " << fetcher->GetResponseCode();
+    int net_error;
+    {
+      const net::URLRequestStatus& status = fetcher->GetStatus();
+      if (status.status() == net::URLRequestStatus::FAILED)
+        net_error = status.error();
+      else
+        net_error = net::OK;

[davidben, 2014/10/30 22:26:55]

+mmenke: FYI, here's another one of these. We really should go through and make
it so that you can query status.error() directly or something.

[mmenke, 2014/10/30 22:42:59]

I'd like to get rid of the double-value status entirely, and just make it a
NetError.

Sadly, to be sure this works properly, this code should probably check for:

status.status() == net::URLRequestStatus::FAILED && status.error() !=
net::ERR_ABORTED

[Deprecated (see juliatuttle), 2014/10/31 18:54:01]

Why does ERR_ABORTED not count?

[mmenke, 2014/10/31 18:55:55]

The same reason you're not counting net::URLRequestStatus:CANCELED.  IF you want
to count cancelled requests, should count those, too.  Don't ask why we have two
ways to indicate a request was cancelled.

[Deprecated (see juliatuttle), 2014/10/31 21:25:39]

Alright, I'm counting CANCELED as ERR_ABORTED.

+    }
+    int http_response_code = fetcher->GetResponseCode();
+
+    VLOG(1) << "Upload finished with net error " << net_error <<
+               " and HTTP response code " << http_response_code;
 
     UMA_HISTOGRAM_SPARSE_SLOWLY("DomainReliability.UploadResponseCode",
-                                fetcher->GetResponseCode());
+                                http_response_code);
+    UMA_HISTOGRAM_SPARSE_SLOWLY("DomainReliability.UploadNetError",
+                                -net_error);

[davidben, 2014/10/30 22:26:55]

Should this be

UMA_HISTOGRAM_CUSTOM_ENUMERATION("DomainReliability.UploadNetError",
                                 -net_error,
                                 net::GetAllErrorCodesForUma());

We're not very consistent about this. Perhaps ask the histograms.xml reviewer
which is preferred?

[Deprecated (see juliatuttle), 2014/10/31 18:54:01]

This is rare enough that I think a sparse one will save a lot of RAM.

 
-    bool success = fetcher->GetResponseCode() == 200;
-    callback_it->second.Run(success);
+    callback_it->second.Run(http_response_code == 200);
 
     delete callback_it->first;
     upload_callbacks_.erase(callback_it);