Make certificate import more failure tolerant

If an error occurs while trying to import certificate in to webserver
configuration, the script will now set a marker file to the related
domain and tries again to import the cert in next script run.
Before those failures have been reported in log, but there was no
treatment.

[FS#136](https://fs.golderweb.de/index.php?do=details&task_id=136)

letsencrypt-renew.sh

@@ -42,12 +42,39 @@ if [ ! -d "${LECONFIGDIR}" ]; then
 	exit 1
 fi
 
+# import_certificate
+#
+# Try to import certificate in webserver config using uberspace-add-certificate
+#
+# If something fails, leave a file as marker so we can try it again with next
+# script run. Failures occur occasionally due to problems with connection to
+# letsencrypt while import.
+import_certificate() {
+	# import certificate
+	uberspace-add-certificate -k "${LECONFIGDIR}/live/${domain}/privkey.pem" -c "${LECONFIGDIR}/live/${domain}/cert.pem"
+
+	# Not successfull?
+	if [ $? -ne 0 ]; then
+		# Set error marker
+		touch "${LECONFIGDIR}/live/${domain}/importerror"
+	elif [ -f "${LECONFIGDIR}/live/${domain}/importerror" ]; then
+		# Remove error marker
+		rm "${LECONFIGDIR}/live/${domain}/importerror"
+	fi
+}
+
 # Get all existing inifiles matching namescheme cli-${domain}.ini
 for inifile in "${LECONFIGDIR}"/cli-*.ini; do
 
 	# Get domain out of file (first value in property "domains")
 	domain=$(grep -e "[ \t]*domains.*" "${inifile}" | sed "s/ //g" |cut -d "=" -f2 | cut -d "," -f1)
 
+	# If there was an import error before, try again to import certificate
+	if [ -f "${LECONFIGDIR}/live/${domain}/importerror" ]; then
+
+		import_certificate
+	fi
+
 	# sleep for a random time so not all certificates get renewed at the same time
 	if [ $FIRSTITER -ne 1 ]; then
 		sleep $(expr $RANDOM % 600)
@@ -60,7 +87,6 @@ for inifile in "${LECONFIGDIR}"/cli-*.ini; do
 	FIRSTITER=0
 	letsencrypt certonly -c "${inifile}" || continue
 
-	# import certificate
-	uberspace-add-certificate -k "${LECONFIGDIR}/live/${domain}/privkey.pem" -c "${LECONFIGDIR}/live/${domain}/cert.pem"
+	import_certificate
 
 done