Removed nearly all usage of 'apt-get'.

Primary cause of false Travis CI failures was running 'apt-get update'.
Refactored all instances where this was needed with manually fetching and installing dependencies in S3 instace.

This also includes GCC installation.

.travis.yml

@@ -19,36 +19,28 @@ os: linux
 dist: xenial
 
 
+env:
+  global:
+    - deps_url="https://mbed-os-ci.s3-eu-west-1.amazonaws.com/jenkins-ci/deps"
+    - deps_dir="${HOME}/.cache/deps"
+
+cache:
+
 cache:
   pip: true
   directories:
-    - $HOME/.cache/apt
-    - $HOME/gcc-arm-none-eabi-6-2017-q2-update
+    - $HOME/.cache/deps
 
 
 before_install:
   - source tools/test/travis-ci/functions.sh
   - set_status "pending" "Test started."
 
-  # Make sure pipefail
-  #- set -o pipefail
-  # Setup apt to cache
-  #- mkdir -p $HOME/.cache/apt/partial
-  #- sudo rm -rf /var/cache/apt/archives
-  #- sudo ln -s $HOME/.cache/apt /var/cache/apt/archives
-  # Setup ppa to make sure arm-none-eabi-gcc is correct version
-  #- sudo add-apt-repository -y ppa:team-gcc-arm-embedded/ppa
-  #- sudo add-apt-repository -y ppa:deadsnakes/ppa
-  # workaround for https://travis-ci.community/t/then-sudo-apt-get-update-failed-public-key-is-not-available-no-pubkey-6b05f25d762e3157-in-ubuntu-xenial/1728
-  #- sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 762E3157
-  # Loop until update succeeds (timeouts can occur)
-  #- travis_retry $(! sudo apt-get update 2>&1 |grep Failed)
-
 after_success:
   - set_status "success" "Success!"
 
 after_failure:
-  -set_status "failure" "Test failed."
+  - set_status "failure" "Test failed."
 
 
 matrix:
@@ -83,19 +75,6 @@ matrix:
     ### Docs Tests ###
     - &docs-vm
       stage: "Docs"
-      name: "spellcheck"
-      env: NAME=doxy-spellcheck
-      install:
-        - sudo apt-get install aspell
-      script:
-        # Run local testing on header file doxy
-        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh drivers
-        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh platform
-        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh events
-        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh rtos
-        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh features/netsocket
-
-    - <<: *docs-vm
       name: "astyle"
       env: NAME=astyle
       install:
@@ -117,16 +96,23 @@ matrix:
             | ( grep -v -f .astyleignore || true ) \
             | while read file; do astyle -n --options=.astylerc "${file}"; done
         - git diff --exit-code --diff-filter=d --color
+
+    - <<: *docs-vm
+      name: "spellcheck"
+      env: NAME=doxy-spellcheck
+      install:
+        - source_pkg aspell
+      script:
+        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh drivers
+        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh platform
+        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh events
+        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh rtos
+        - ./tools/test/travis-ci/doxy-spellchecker/spell.sh features/netsocket
 
     - <<: *docs-vm
       name: "doxygen"
       env: NAME=docs
       install:
-        # Install dependencies
-        - sudo apt-get install doxygen
-        # Print versions we use
-        - doxygen --version
-      before_script:
         # Build doxygen
         - >
           (git clone --depth=1 --single-branch --branch Release_1_8_14 https://github.com/doxygen/doxygen;
@@ -165,12 +151,13 @@ matrix:
       stage: "Pytest"
       name: "tools-py27"
       env: NAME=tools-py2.7
+      language: python
       python: 2.7
       install:
-        # Install dependencies
-        - sudo apt-get install gcc-arm-embedded
+        # Install gcc
+        - source_pkg gcc
         - arm-none-eabi-gcc --version
-        # Add additional dependencies specific for testing
+        # Install additional python modules
         - python --version
         - |-
           tr -d ' ' >> requirements.txt <<< "
@@ -181,7 +168,8 @@ matrix:
           coverage>=4.5,<5
           coveralls>=1.5,<2
           "
-        # ... and install.
+        - python -m pip install --upgrade pip==18.1
+        - python -m pip install --upgrade setuptools==40.4.3
         - pip install -r requirements.txt
         - pip list --verbose
       script:
@@ -190,8 +178,6 @@ matrix:
         - python tools/test/pylint.py
         - coverage run -a tools/project.py -S | sed -n '/^Total/p'
         - coverage html
-      after_success:
-        # Coverage for tools
         - coveralls
 
     - <<: *pytools-vm
@@ -217,21 +203,22 @@ matrix:
       env: NAME=psa-autogen
       language: python
       python: 3.7
+      install:
+        # Install gcc
+        - source_pkg gcc
+        - arm-none-eabi-gcc --version
+        # Install python modules
+        - python -m pip install --upgrade pip==18.1
+        - python -m pip install --upgrade setuptools==40.4.3
+        - pip install -r requirements.txt
+        - pip list --verbose
       script:
         - python tools/psa/generate_partition_code.py
         - git diff --exit-code
 
     - <<: *extended-vm
       name: "events"
       env: NAME=events EVENTS=events
-      install:
-        # Install dependencies
-        - sudo apt-get install gcc-arm-embedded
-        - pip install -r requirements.txt
-        # Print versions we use
-        - arm-none-eabi-gcc --version
-        - gcc --version
-        - python --version
       script:
         # Check that example compiles
         - sed -n '/``` cpp/,/```/{/```$/Q;/```/d;p;}' $EVENTS/README.md > main.cpp
@@ -264,13 +251,17 @@ matrix:
       name: "littlefs"
       env: NAME=littlefs LITTLEFS=features/storage/filesystem/littlefs
       install:
-        # Install dependencies
-        - sudo apt-get install gcc-arm-embedded fuse libfuse-dev
-        - pip install -r requirements.txt
-        # Print versions
+        # Install gcc
+        - source_pkg gcc
         - arm-none-eabi-gcc --version
-        - gcc --version
-        - python --version
+        # Install python modules
+        - python -m pip install --upgrade pip==18.1
+        - python -m pip install --upgrade setuptools==40.4.3
+        - pip install -r requirements.txt
+        - pip list --verbose
+        # Install test-specific packages
+        - source_pkg fuse
+        - source_pkg libfuse-dev
         - fusermount --version
       before_script:
         # Setup and patch littlefs-fuse

tools/test/travis-ci/functions.sh

@@ -18,21 +18,128 @@
 
 set -o pipefail
 
-info() { echo "I: ${1}"; }
-die() { echo "E: ${1}" 1>&2; exit ${2:-1}; }
+info() { echo -e "I: ${1}"; }
+die() { echo -e "E: ${1}" 1>&2; exit ${2:-1}; }
 
 set_status()
 {
-  local _name=${NAME}
-  local _payload=$(<<< "
+  local job_name=${NAME}
+  local payload=$(<<< "
   {
     'state': '${1}',
     'description': '${2}',
-    'context': 'travis-ci/${_name}',
+    'context': 'travis-ci/${job_name}',
     'target_url': 'https://travis-ci.org/${TRAVIS_REPO_SLUG}/jobs/${TRAVIS_JOB_ID}'
   }" tr '"' '"')
 
   curl --silent --output /dev/null --user "${MBED_BOT}" --request POST \
     "https://api.github.com/repos/${TRAVIS_REPO_SLUG}/statuses/${TRAVIS_PULL_REQUEST_SHA:-$TRAVIS_COMMIT}" \
     --data @- <<< "${payload}"
 }
+
+
+_install_gcc()
+{
+  local url="${deps_url}/gcc6-linux.tar.bz2"
+  local gcc_path="${deps_dir}/gcc/gcc-arm-none-eabi-6-2017-q2-update/"
+  local archive="gcc.tar.bz2"
+
+  info "URL: ${url}"
+
+  if [ ! -d "${deps_dir}/gcc" ]; then
+
+    info "Downloading archive"
+    curl --location "${url}" --output "${deps_dir}/${archive}"
+    ls -al "${deps_dir}"
+
+    info "Extracting 'gcc'"
+    mkdir -p "${deps_dir}/gcc"
+    tar -xf "${deps_dir}/${archive}" -C "${deps_dir}/gcc"
+    rm "${deps_dir}/${archive}"
+
+  fi
+
+  info "Installing 'gcc'"
+  export "PATH=${gcc_path}/bin:${PATH}"
+} 
+
+
+_fetch_deps()
+{
+  local pkg="${1}"
+  local dep_list="${2}"
+
+  info "Fetching '${pkg}' archives"
+
+  while read dep; do
+
+    curl --location "${deps_url}/${dep}.deb" \
+      --output "${deps_dir}/${dep}.deb" \
+      || die "Download failed ('${dep}')" \
+      && info "Fetched ${deps_url}/${dep}.deb" &
+
+  done <<< "${dep_list}"
+
+  wait
+}
+
+_install_deps()
+{
+  local pkg="${1}"
+  local dep_list="${2}"
+
+  # Assume that if the first package isn't cached, none are.
+  local first_dep=$(<<< "${dep_list}" head -n1)
+  [ ! -f "${deps_dir}/${first_dep}.deb" ] && _fetch_deps "${pkg}" "${dep_list}"
+
+  # Install dependencies
+  info "Installing '${pkg}' packages"
+  sudo dpkg -i $(<<< "${dep_list}" sed -e 's_^ *__' -e 's_^\(.*\)$_'"${deps_dir}"'/\1.deb_' | tr $'\n' ' ')
+}
+
+
+source_pkg()
+{
+  local pkg="${1}"
+
+  local aspell_deps="aspell
+    aspell-en
+    dictionaries-common
+    libaspell15"
+
+  local libfuse_deps="libfuse-dev
+    libpcre3-dev
+    libpcre32-3
+    libpcrecpp0v5
+    libselinux1-dev
+    libsepol1-dev
+    libc-bin"
+
+
+  case "${pkg}" in
+
+    "fuse" )
+      sudo apt-get -o=dir::cache="${deps_dir}/apt-get" install fuse \
+        || die "Installation failed"
+      ;;
+
+    "aspell" )
+      _install_deps aspell "${aspell_deps}" \
+        || die "Installation failed"
+      ;;
+    "libfuse-dev" )
+      _install_deps libfuse-dev "${libfuse_deps}" \
+        || die "Installation failed"
+      ;;
+
+    "gcc" )
+      _install_gcc \
+        || die "Installation failed"
+      ;;
+
+    * )
+      die "Package not supported: '${pkg}'"
+      ;;
+
+  esac
+}