File 0003-httputil-improve-detection-of-unavailable-... of Package snapd

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File 0003-httputil-improve-detection-of-unavailable-DNS-server.patch of Package snapd (Revision def28b2bdd6ef69282e13df91f803c2d)

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From 17778055937a37de27caf5e1251162161ff79ecd Mon Sep 17 00:00:00 2001
From: Zygmunt Krynicki <me@zygoon.pl>
Date: Thu, 30 May 2019 14:23:26 +0200
Subject: [PATCH 3/4] httputil: improve detection of unavailable DNS servers

When we detect if the DNS server is unavailable, in response to a HTTP
request error, we unpack the returned error object, hoping to reach
net.DNSError. When the error message contained therein contains the text

Temporary failure in name resolution

We understand that this really conveys the fact we cannot talk to the
DNS sever. This error message, however, depends on the golang DNS
backend, either native or cgo. Similar check in ShouldRetryError
carries a separate test for another message:

connection refused

When running unit tests inside the open build service the network setup
is such that we hit this case exactly, with the returned errors being:

[   44s] nesting 2: &net.DNSError{Err:"read udp [::1]:58819->[::1]:53: read: connection refused", Name:"nonexistingserver909123.com", Server:"[::1]:53", IsTimeout:false, IsTemporary:true}

This patch extends the check to handle both situations.

Signed-off-by: Zygmunt Krynicki <me@zygoon.pl>
---
 httputil/retry.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/httputil/retry.go b/httputil/retry.go
index b756e256ba..b4071067ce 100644
--- a/httputil/retry.go
+++ b/httputil/retry.go
@@ -178,7 +178,7 @@ func isDnsUnavailable(err error) bool {
 	// not exposed in net.DNSError and in go-1.10 it is not even
 	// a temporary error so there is no way to distiguish it other
 	// than a fugly string compare on a (potentially) localized string
-	return strings.Contains(dnsErr.Err, "Temporary failure in name resolution")
+	return strings.Contains(dnsErr.Err, "connection refused") || strings.Contains(dnsErr.Err, "Temporary failure in name resolution")
 }
 
 // RetryRequest calls doRequest and read the response body in a retry loop using the given retryStrategy.
-- 
2.21.0

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File 0003-httputil-improve-detection-of-unavailable-DNS-server.patch of Package snapd (Revision def28b2bdd6ef69282e13df91f803c2d)

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