[PATCH v2] travis-ci: retry if Git for Windows CI returns HTTP error 502 or 503

The Git for Windows CI web app sometimes returns HTTP errors of "502 bad gateway" or "503 service unavailable" [1]. We also need to check the HTTP content because the GfW web app seems to pass through (error) results from other Azure calls with HTTP code 200. Wait a little and retry the request if this happens.

[1] https://docs.microsoft.com/en-in/azure/app-service-web/app-service-web-troubleshoot-http-502-http-503

Signed-off-by: Lars Schneider <larsxschneider@gmail.com>
---

Hi Junio,

I can't really test this as my TravisCI account does not have the extended timeout and I am unable to reproduce the error.

It would be great if we could test this is a little bit in pu.

Thanks, Lars

Notes:
    Base Ref: next
    Web-Diff: https://github.com/larsxschneider/git/commit/af0f0f0eb8
    Checkout: git fetch https://github.com/larsxschneider/git travisci/win-retry-v2 && git checkout af0f0f0eb8

    Interdiff (v1..v2):

    diff --git a/ci/run-windows-build.sh b/ci/run-windows-build.sh
    index 7a9aa9c6a7..3e5a0abee0 100755
    --- a/ci/run-windows-build.sh
    +++ b/ci/run-windows-build.sh
    @@ -14,26 +14,33 @@ COMMIT=$2

     gfwci () {
     	local CURL_ERROR_CODE HTTP_CODE
    -	exec 3>&1
    +	CONTENT_FILE=$(mktemp -t "git-windows-ci-XXXXXX")
     	while test -z $HTTP_CODE
     	do
     	HTTP_CODE=$(curl \
     		-H "Authentication: Bearer $GFW_CI_TOKEN" \
     		--silent --retry 5 --write-out '%{HTTP_CODE}' \
    -		--output >(sed "$(printf '1s/^\xef\xbb\xbf//')" >cat >&3) \
    +		--output >(sed "$(printf '1s/^\xef\xbb\xbf//')" >$CONTENT_FILE) \
     		"https://git-for-windows-ci.azurewebsites.net/api/TestNow?$1" \
     	)
     	CURL_ERROR_CODE=$?
     		# The GfW CI web app sometimes returns HTTP errors of
     		# "502 bad gateway" or "503 service unavailable".
    -		# Wait a little and retry if it happens. More info:
    +		# We also need to check the HTTP content because the GfW web
    +		# app seems to pass through (error) results from other Azure
    +		# calls with HTTP code 200.
    +		# Wait a little and retry if we detect this error. More info:
     		# https://docs.microsoft.com/en-in/azure/app-service-web/app-service-web-troubleshoot-http-502-http-503
    -		if test $HTTP_CODE -eq 502 || test $HTTP_CODE -eq 503
    +		if test $HTTP_CODE -eq 502 ||
    +		   test $HTTP_CODE -eq 503 ||
    +		   grep "502 - Web server received an invalid response" $CONTENT_FILE >/dev/null
     		then
     			sleep 10
     			HTTP_CODE=
     		fi
     	done
    +	cat $CONTENT_FILE
    +	rm $CONTENT_FILE
     	if test $CURL_ERROR_CODE -ne 0
     	then
     		return $CURL_ERROR_CODE

    \0

 ci/run-windows-build.sh | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)