From c6a1c47d4021a6c9a0c8820b0052f148474d6bec Mon Sep 17 00:00:00 2001
From: Nestal Wan <me@nestal.net>
Date: Fri, 20 Jul 2012 00:50:40 +0800
Subject: [PATCH] added retry on HTTP 500 & 503 (#82)

---
 libgrive/src/http/CurlAgent.cc     |  2 +-
 libgrive/src/protocol/AuthAgent.cc | 47 ++++++++++++++++++++++++++----
 libgrive/src/protocol/AuthAgent.hh |  1 +
 libgrive/src/util/OS.cc            | 13 +++++++++
 libgrive/src/util/OS.hh            |  2 ++
 5 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/libgrive/src/http/CurlAgent.cc b/libgrive/src/http/CurlAgent.cc
index ef70d693..85dfe38e 100644
--- a/libgrive/src/http/CurlAgent.cc
+++ b/libgrive/src/http/CurlAgent.cc
@@ -156,7 +156,7 @@ long CurlAgent::ExecCurl(
 	Trace( "HTTP response %1%", http_code ) ;
 	::curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, 	0 ) ;
 	
-	if ( curl_code != CURLE_OK || http_code >= 400 )
+	if ( curl_code != CURLE_OK || (http_code >= 400 && http_code < 500) )
 	{
 		BOOST_THROW_EXCEPTION(
 			Error()
diff --git a/libgrive/src/protocol/AuthAgent.cc b/libgrive/src/protocol/AuthAgent.cc
index 06cacd21..b54f2324 100644
--- a/libgrive/src/protocol/AuthAgent.cc
+++ b/libgrive/src/protocol/AuthAgent.cc
@@ -18,7 +18,10 @@
 */
 
 #include "AuthAgent.hh"
+
 #include "http/Header.hh"
+#include "util/log/Log.hh"
+#include "util/OS.hh"
 
 #include <cassert>
 
@@ -47,7 +50,11 @@ long AuthAgent::Put(
 	Receivable			*dest,
 	const Header&		hdr )
 {
-	return m_agent->Put( url, data, dest, AppendHeader(hdr) ) ;
+	long response ;
+	while ( CheckRetry(
+		response = m_agent->Put(url, data, dest, AppendHeader(hdr)) ) ) ;
+	
+	return response ;
 }
 
 long AuthAgent::Put(
@@ -56,7 +63,11 @@ long AuthAgent::Put(
 	Receivable			*dest,
 	const Header&		hdr )
 {
-	return m_agent->Put( url, file, dest, AppendHeader(hdr) ) ;
+	long response ;
+	while ( CheckRetry(
+		response = m_agent->Put( url, file, dest, AppendHeader(hdr) ) ) ) ;
+	
+	return response ;
 }
 
 long AuthAgent::Get(
@@ -64,7 +75,11 @@ long AuthAgent::Get(
 	Receivable			*dest,
 	const Header&		hdr )
 {
-	return m_agent->Get( url, dest, AppendHeader(hdr) ) ;
+	long response ;
+	while ( CheckRetry(
+		response = m_agent->Get( url, dest, AppendHeader(hdr) ) ) ) ;
+	
+	return response ;
 }
 
 long AuthAgent::Post(
@@ -73,7 +88,11 @@ long AuthAgent::Post(
 	Receivable			*dest,
 	const Header&		hdr )
 {
-	return m_agent->Post( url, data, dest, AppendHeader(hdr) ) ;
+	long response ;
+	while ( CheckRetry(
+		response = m_agent->Post( url, data, dest, AppendHeader(hdr) ) ) ) ;
+	
+	return response ;
 }
 
 long AuthAgent::Custom(
@@ -82,7 +101,11 @@ long AuthAgent::Custom(
 	Receivable			*dest,
 	const Header&		hdr )
 {
-	return m_agent->Custom( method, url, dest, AppendHeader(hdr) ) ;
+	long response ;
+	while ( CheckRetry(
+		response = m_agent->Custom( method, url, dest, AppendHeader(hdr) ) ) ) ;
+	
+	return response ;
 }
 
 std::string AuthAgent::RedirLocation() const
@@ -100,4 +123,18 @@ std::string AuthAgent::Unescape( const std::string& str )
 	return m_agent->Unescape( str ) ;
 }
 
+bool AuthAgent::CheckRetry( long response )
+{
+	if ( response == 500 || response == 503 )
+	{
+		Log( "resquest failed due to temperory error: %1%. retrying in 5 seconds",
+			response, log::warning ) ;
+			
+		os::Sleep( 5 ) ;
+		return true ;
+	}
+	else
+		return false ;
+}
+
 } // end of namespace
diff --git a/libgrive/src/protocol/AuthAgent.hh b/libgrive/src/protocol/AuthAgent.hh
index d3fb0534..3b198c60 100644
--- a/libgrive/src/protocol/AuthAgent.hh
+++ b/libgrive/src/protocol/AuthAgent.hh
@@ -72,6 +72,7 @@ public :
 
 private :
 	http::Header AppendHeader( const http::Header& hdr ) const ;
+	bool CheckRetry( long response ) ;
 	
 private :
 	OAuth2								m_auth ;
diff --git a/libgrive/src/util/OS.cc b/libgrive/src/util/OS.cc
index 0d51136b..5bf2f663 100644
--- a/libgrive/src/util/OS.cc
+++ b/libgrive/src/util/OS.cc
@@ -81,4 +81,17 @@ void SetFileTime( const std::string& filename, const DateTime& t )
 		) ;
 }
 
+void Sleep( unsigned int sec )
+{
+	struct timespec ts = { sec, 0 } ;
+	
+	int result = 0 ;
+	do
+	{
+		struct timespec rem ;
+		nanosleep( &ts, &rem ) ;
+		ts = rem ;
+	} while ( result == -1 && errno == EINTR ) ;
+}
+
 } } // end of namespaces
diff --git a/libgrive/src/util/OS.hh b/libgrive/src/util/OS.hh
index 4a0350dc..31ab51de 100644
--- a/libgrive/src/util/OS.hh
+++ b/libgrive/src/util/OS.hh
@@ -38,6 +38,8 @@ namespace os
 	
 	void SetFileTime( const std::string& filename, const DateTime& t ) ;
 	void SetFileTime( const fs::path& filename, const DateTime& t ) ;
+	
+	void Sleep( unsigned int sec ) ;
 }
 
 } // end of namespaces