.travis.yml: Prevent nightly jobs from timing out (again) (netdata#7238)

* .travis.yml: Add tick() and retry() functions

* .travis.yml: Remove superfluous 'docker info' commands

The docker info command is ran during the install phase. There is no
need to run it again

* .travis.yml: Use the tick() function instead of travis_wait()

Author: knatsakis

.travis.yml

@@ -10,7 +10,8 @@ matrix:
   allow_failures:
     - env: ALLOW_SOFT_FAILURE_HERE=true
 
-
+before_install:
+  - source .travis/utils.sh
 
 # Install dependencies for all, once
 #
@@ -493,10 +494,9 @@ jobs:
           - echo "Last commit:" && git log -1
           - echo "GIT Describe:" && git describe
           - echo "packaging/version:" && cat packaging/version
-          - docker info
           - packaging/docker/check_login.sh
             && echo "Switching to latest master branch, to pick up tagging if any" && git checkout master && git pull
-            && travis_wait 20 packaging/docker/build.sh
+            && tick packaging/docker/build.sh
             && packaging/docker/publish.sh
         after_failure: post_message "TRAVIS_MESSAGE" "<!here> Docker image publishing failed"
 
@@ -591,9 +591,8 @@ jobs:
           - echo "Last commit:" && git log -1
           - echo "GIT Describe:" && git describe
           - echo "packaging/version:" && cat packaging/version
-          - docker info
           - packaging/docker/check_login.sh
-            && travis_wait 20 packaging/docker/build.sh
+            && tick packaging/docker/build.sh
             && packaging/docker/publish.sh
         after_failure: post_message "TRAVIS_MESSAGE" "<!here> Nightly docker image publish failed"
 

.travis/utils.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+# Prevent travis from timing out after 10 minutes of no output
+tick() {
+	(while true; do sleep 300; echo; done) &
+	local PID=$!
+	disown
+
+	"$@"
+	local RET=$?
+
+	kill $PID
+	return $RET
+}
+
+retry() {
+	local tries=$1
+	shift
+
+	local i=0
+	while [ "$i" -lt "$tries" ]; do
+		"$@" && return 0
+		sleep $((2**((i++))))
+	done
+
+	return 1
+}