External Print Servers: Logs in device-log

This patch adds new entries to chrome://device-log with information about:
- the length of a resultant list of print servers calculated from policies
- results of querying each print servers (number of printers or error)
- the length of a final list of server printers.

BUG=chromium:1018552
TEST=tested on nautilus

Change-Id: I73516f73e3608e87b59d2a6980fbb52367d45ea4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1882650Reviewed-by: Sean Kau <skau@chromium.org>
Reviewed-by: Luum Habtemariam <luum@chromium.org>
Commit-Queue: Piotr Pawliczek <pawliczek@chromium.org>
Auto-Submit: Piotr Pawliczek <pawliczek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#710307}

chrome/browser/chromeos/printing/cups_printers_manager.cc

@@ -31,6 +31,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/pref_names.h"
 #include "chromeos/services/network_config/public/mojom/cros_network_config.mojom.h"
+#include "components/device_event_log/device_event_log.h"
 #include "components/policy/policy_constants.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/pref_member.h"
@@ -282,8 +283,13 @@ class CupsPrintersManagerImpl
 
   // Callback for ServerPrintersProvider.
   void OnPrintersUpdated(bool complete) {
-    OnPrintersFound(kPrintServerDetector,
-                    server_printers_provider_->GetPrinters());
+    const std::vector<PrinterDetector::DetectedPrinter> printers =
+        server_printers_provider_->GetPrinters();
+    if (complete) {
+      PRINTER_LOG(EVENT) << "The list of server printers has been completed. "
+                         << "Number of server printers: " << printers.size();
+    }
+    OnPrintersFound(kPrintServerDetector, printers);
   }
 
  private:

chrome/browser/chromeos/printing/server_printers_fetcher.cc

@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/hash/md5.h"
+#include "base/logging.h"
 #include "base/memory/scoped_refptr.h"
 #include "base/sequence_checker.h"
 #include "base/sequenced_task_runner.h"
@@ -15,6 +16,7 @@
 #include "base/task/task_traits.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/net/system_network_context_manager.h"
+#include "components/device_event_log/device_event_log.h"
 #include "net/base/load_flags.h"
 #include "services/network/public/cpp/resource_request.h"
 #include "services/network/public/cpp/simple_url_loader.h"
@@ -42,9 +44,11 @@ class ServerPrintersFetcher::PrivateImplementation
  public:
   PrivateImplementation(const ServerPrintersFetcher* owner,
                         const GURL& server_url,
+                        const std::string& server_name,
                         ServerPrintersFetcher::OnPrintersFetchedCallback cb)
       : owner_(owner),
         server_url_(server_url),
+        server_name_(server_name),
         callback_(std::move(cb)),
         task_runner_(base::CreateSequencedTaskRunner(
             {base::ThreadPool(), base::TaskShutdownBehavior::BLOCK_SHUTDOWN})) {
@@ -75,6 +79,9 @@ class ServerPrintersFetcher::PrivateImplementation
   void OnComplete(bool success) override {
     DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
     if (!success) {
+      PRINTER_LOG(ERROR) << "Error when querying the print server "
+                         << server_name_
+                         << ": NetError=" << simple_url_loader_->NetError();
       // Some error occurred. Call the callback with an empty vector.
       PostResponse({});
       return;
@@ -87,11 +94,13 @@ class ServerPrintersFetcher::PrivateImplementation
         !client.ParseResponseAndSaveTo(&response)) {
       // Parser has failed. Dump errors to the log.
       std::string message = "Cannot parse response from the print server " +
-                            server_url_.spec() + ". Parser log:";
+                            server_name_ + ". Parser log:";
       for (const auto& entry : client.GetErrorLog()) {
         message += "\n * " + entry.message;
       }
       LOG(WARNING) << message;
+      PRINTER_LOG(ERROR) << "Error when querying the print server "
+                         << server_name_ << ": unparsable IPP response.";
       // Call the callback with an empty vector and exit.
       PostResponse({});
       return;
@@ -105,6 +114,9 @@ class ServerPrintersFetcher::PrivateImplementation
       InitializePrinter(&(printers[i].printer), name);
     }
     // Call the callback with queried printers.
+    PRINTER_LOG(DEBUG) << "The print server " << server_name_ << " returned "
+                       << printers.size() << " printer"
+                       << (printers.size() == 1 ? "." : "s.");
     PostResponse(std::move(printers));
   }
 
@@ -185,6 +197,7 @@ class ServerPrintersFetcher::PrivateImplementation
 
   const ServerPrintersFetcher* owner_;
   const GURL server_url_;
+  const std::string server_name_;
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_for_callback_;
   ServerPrintersFetcher::OnPrintersFetchedCallback callback_;
@@ -200,8 +213,12 @@ class ServerPrintersFetcher::PrivateImplementation
 };
 
 ServerPrintersFetcher::ServerPrintersFetcher(const GURL& server_url,
+                                             const std::string& server_name,
                                              OnPrintersFetchedCallback cb)
-    : pim_(new PrivateImplementation(this, server_url, std::move(cb)),
+    : pim_(new PrivateImplementation(this,
+                                     server_url,
+                                     server_name,
+                                     std::move(cb)),
            PimDeleter()) {}
 
 void ServerPrintersFetcher::PimDeleter::operator()(

chrome/browser/chromeos/printing/server_printers_fetcher.h

@@ -32,7 +32,9 @@ class ServerPrintersFetcher {
       const GURL& server_url,
       std::vector<PrinterDetector::DetectedPrinter>&& printers)>;
 
-  ServerPrintersFetcher(const GURL& server_url, OnPrintersFetchedCallback cb);
+  ServerPrintersFetcher(const GURL& server_url,
+                        const std::string& server_name,
+                        OnPrintersFetchedCallback cb);
   virtual ~ServerPrintersFetcher();
 
  private:

chrome/browser/chromeos/printing/server_printers_provider.cc

@@ -18,6 +18,7 @@
 #include "chrome/browser/chromeos/printing/print_servers_provider_factory.h"
 #include "chrome/browser/chromeos/printing/server_printers_fetcher.h"
 #include "chrome/browser/profiles/profile.h"
+#include "components/device_event_log/device_event_log.h"
 #include "url/gurl.h"
 
 namespace chromeos {
@@ -69,6 +70,11 @@ class ServerPrintersProviderImpl
   void OnServersChanged(bool servers_are_complete,
                         const std::vector<PrintServer>& servers) override {
     DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
+    // Create an entry in the device log.
+    if (servers_are_complete) {
+      PRINTER_LOG(EVENT) << "The list of print servers has been completed. "
+                         << "Number of print servers: " << servers.size();
+    }
     // Save previous state.
     const bool previous_complete = IsComplete();
     // Initialize new state.
@@ -77,6 +83,7 @@ class ServerPrintersProviderImpl
     std::map<GURL, PrintServerWithPrinters> new_servers;
     for (const auto& server : servers) {
       const GURL& url = server.GetUrl();
+      const std::string& name = server.GetName();
       auto it_new = new_servers.emplace(url, server).first;
       auto it_old = servers_.find(url);
       if (it_old != servers_.end()) {
@@ -88,7 +95,8 @@ class ServerPrintersProviderImpl
         // This is a new print server: query for printers.
         fetchers_.emplace(
             url, std::make_unique<ServerPrintersFetcher>(
-                     url, base::BindRepeating(
+                     url, name,
+                     base::BindRepeating(
                          &ServerPrintersProviderImpl::OnPrintersFetched,
                          weak_ptr_factory_.GetWeakPtr())));
       }