Refactor .travis.yml by introducing travis_retry.sh

Not using official travis_retry.bash, because it's not supporting to
modify backoff seconds.
0ad8f1886b/lib/travis/build/bash/travis_retry.bash

Not using official `travis_apt_get_update` function because it does not
propagate exit status to be used by retries.
0ad8f1886b/lib/travis/build/bash/travis_apt_get_update.bash

Co-Authored-By: Nobuyoshi Nakada <nobu@ruby-lang.org>

.travis.yml

@@ -88,16 +88,10 @@ env:
     #     sources:
     #       - ubuntu-toolchain-r-test
     before_install:
+      - tool/travis_retry.sh sudo -E apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
+      - tool/travis_retry.sh bash -c "sudo rm -rf '${TRAVIS_ROOT}/var/lib/apt/lists/'* && sudo apt-get update -yq"
       - |-
-        for seconds in 1 25 100 -1; do
+        tool/travis_retry.sh sudo -E apt-get -yq --no-install-suggests --no-install-recommends $travis_apt_get_options install \
-          sudo -E apt-add-repository -y "ppa:ubuntu-toolchain-r/test" && break
-          sleep "$seconds" || exit 1
-        done
-      - |-
-        for seconds in 1 25 100 -1; do
-          travis_apt_get_update
-
-          sudo -E apt-get -yq --no-install-suggests --no-install-recommends $travis_apt_get_options install \
           gcc-8 \
           libffi-dev \
           libgdbm-dev \
@@ -110,27 +104,21 @@ env:
           libyaml-dev \
           openssl \
           valgrind \
-            zlib1g-dev \
+          zlib1g-dev
-          && break
-
-          sleep "$seconds" || exit 1
-        done
 
   - &clang-8
     compiler: clang-8
     addons:
       apt:
-        config:
+        # Not doing this manually unlike other sources, because it has been stable.
-          retries: true
         sources:
           - llvm-toolchain-xenial-8
-        # `packages` are installed in `before_install` for retries.
+        config:
+          retries: true
     before_install:
+      - tool/travis_retry.sh bash -c "sudo rm -rf '${TRAVIS_ROOT}/var/lib/apt/lists/'* && sudo apt-get update -yq"
       - |-
-        for seconds in 1 25 100 -1; do
+        tool/travis_retry.sh sudo -E apt-get -yq --no-install-suggests --no-install-recommends $travis_apt_get_options install \
-          travis_apt_get_update
-
-          sudo -E apt-get -yq --no-install-suggests --no-install-recommends $travis_apt_get_options install \
           clang-8 \
           llvm-8-tools \
           libffi-dev \
@@ -144,11 +132,7 @@ env:
           libyaml-dev \
           openssl \
           valgrind \
-            zlib1g-dev \
+          zlib1g-dev
-          && break
-
-          sleep "$seconds" || exit 1
-        done
 
   # --------
 
@@ -290,16 +274,10 @@ env:
     #     sources:
     #       - ubuntu-toolchain-r-test
     before_install:
+      - tool/travis_retry.sh sudo -E apt-add-repository -y "ppa:ubuntu-toolchain-r/test"
+      - tool/travis_retry.sh bash -c "sudo rm -rf '${TRAVIS_ROOT}/var/lib/apt/lists/'* && sudo apt-get update -yq"
       - |-
-        for seconds in 1 25 100 -1; do
+        tool/travis_retry.sh sudo -E apt-get -yq --no-install-suggests --no-install-recommends $travis_apt_get_options install \
-          sudo -E apt-add-repository -y "ppa:ubuntu-toolchain-r/test" && break
-          sleep "$seconds" || exit 1
-        done
-      - |-
-        for seconds in 1 25 100 -1; do
-          travis_apt_get_update
-
-          sudo -E apt-get -yq --no-install-suggests --no-install-recommends $travis_apt_get_options install \
           gcc-8-multilib \
           libffi-dev:i386 \
           libffi6:i386 \
@@ -314,11 +292,7 @@ env:
           libssl1.0.0:i386 \
           linux-libc-dev:i386 \
           zlib1g-dev:i386 \
-            zlib1g:i386 \
+          zlib1g:i386
-          && break
-
-          sleep "$seconds" || exit 1
-        done
 
   - &pedanticism
     name: -std=c99 -pedantic

tool/travis_retry.sh

@@ -0,0 +1,13 @@
+#!/bin/sh -eu
+# The modified version of `travis_retry` to support custom backoffs, which is used by .travis.yml.
+# https://github.com/travis-ci/travis-build/blob/master/lib/travis/build/bash/travis_retry.bash
+
+for sleep in 0 ${WAITS:- 1 25 100}; do
+  sleep "$sleep"
+
+  echo "+ $@"
+  if "$@"; then
+    exit 0
+  fi
+done
+exit 1