rabbit_ct_vm_helpers, tools/terraform: Pin Elixir version

... if one is specified.

Out-of-the box, rabbit_ct_vm_helpers will take the version of the
Elixir installed on the host starting the testsuite.

deps/rabbitmq_ct_helpers/src/rabbit_ct_vm_helpers.erl

@@ -32,6 +32,7 @@
          ensure_terraform_cmd/1,
          determine_erlang_version/1,
          determine_erlang_git_ref/1,
+         determine_elixir_version/1,
          compute_code_path/1,
          find_terraform_ssh_key/1,
          set_terraform_files_suffix/1,
@@ -71,6 +72,7 @@ setup_steps() ->
      fun ensure_terraform_cmd/1,
      fun determine_erlang_version/1,
      fun determine_erlang_git_ref/1,
+     fun determine_elixir_version/1,
      fun compute_code_path/1,
      fun find_terraform_ssh_key/1,
      fun set_terraform_files_suffix/1,
@@ -159,6 +161,27 @@ determine_erlang_git_ref(Config) ->
     rabbit_ct_helpers:set_config(
       Config, {erlang_git_ref, GitRef}).
 
+determine_elixir_version(Config) ->
+    Version = case rabbit_ct_helpers:get_config(Config, elixir_version) of
+                  undefined ->
+                      case os:getenv("ELIXIR_VERSION") of
+                          false ->
+                              Cmd = ["elixir", "-e", "IO.puts System.version"],
+                              case rabbit_ct_helpers:exec(Cmd) of
+                                  {ok, Output} ->
+                                      string:strip(Output, right, $\n);
+                                  _ ->
+                                      ""
+                              end;
+                          V ->
+                              V
+                      end;
+                  V ->
+                      V
+              end,
+    ct:pal(?LOW_IMPORTANCE, "Elixir version: ~s", [Version]),
+    rabbit_ct_helpers:set_config(Config, {elixir_version, Version}).
+
 compute_code_path(Config) ->
     EntireCodePath = code:get_path(),
     CodePath = rabbit_ct_broker_helpers:filter_out_erlang_code_path(
@@ -480,6 +503,7 @@ destroy_terraform_vms(Config) ->
 terraform_var_flags(Config) ->
     ErlangVersion = ?config(erlang_version, Config),
     GitRef = ?config(erlang_git_ref, Config),
+    ElixirVersion = ?config(elixir_version, Config),
     SshKey = ?config(terraform_ssh_key, Config),
     Suffix = ?config(terraform_files_suffix, Config),
     EC2Region = ?config(terraform_aws_ec2_region, Config),
@@ -508,6 +532,7 @@ terraform_var_flags(Config) ->
     [
      {"-var=erlang_version=~s", [ErlangVersion]},
      {"-var=erlang_git_ref=~s", [GitRef]},
+     {"-var=elixir_version=~s", [ElixirVersion]},
      {"-var=erlang_cookie=~s", [erlang:get_cookie()]},
      {"-var=erlang_nodename=~s", [?ERLANG_REMOTE_NODENAME]},
      {"-var=ssh_key=~s", [SshKey]},

deps/rabbitmq_ct_helpers/tools/terraform/autoscaling-group/main.tf

@@ -10,6 +10,7 @@ module "direct_vms" {
   instance_count = 0
 
   erlang_version = "${var.erlang_version}"
+  elixir_version = "${var.elixir_version}"
   erlang_cookie = "${var.erlang_cookie}"
   erlang_nodename = "${var.erlang_nodename}"
   ssh_key = "${var.ssh_key}"

deps/rabbitmq_ct_helpers/tools/terraform/autoscaling-group/setup-vms.sh

@@ -4,12 +4,12 @@
 set -e
 
 usage() {
-  echo "Syntax: $(basename "$0") [-Dh] [-c <instance_count>] [-s <ssh_key>] <erlang_version> [<erlang_app_dir> ...]"
+  echo "Syntax: $(basename "$0") [-Dh] [-c <instance_count>] [-e <elixir_version>] [-s <ssh_key>] <erlang_version> [<erlang_app_dir> ...]"
 }
 
 instance_count=1
 
-while getopts "c:Dhs:" opt; do
+while getopts "c:e:Dhs:" opt; do
   case $opt in
     h)
       usage
@@ -18,6 +18,9 @@ while getopts "c:Dhs:" opt; do
     c)
       instance_count=$OPTARG
       ;;
+    e)
+      elixir_version=$OPTARG
+      ;;
     D)
       destroy=yes
       ;;
@@ -49,6 +52,10 @@ shift
 
 terraform_dir=$(cd "$(dirname "$0")" && pwd)
 
+erlang_nodename=control
+dirs_archive=dirs-archive.tar.xz
+instance_name_prefix="[$(basename "$0")/$USER] "
+
 canonicalize_erlang_version() {
   version=$1
 
@@ -96,20 +103,12 @@ list_dirs_to_upload() {
     grep -q "^$dir/" "$sorted_manifest" || echo "$dir"
   done < "$sorted_manifest" > "$manifest"
 
-  awk '
-  BEGIN {
-    printf "[";
-  }
-  {
-    if (NR > 1) {
-      printf ",";
-    }
-    printf "\"" $0 "\"";
-  }
-  END {
-    printf "]";
-  }
-  ' "$manifest"
+  tar cf - -P \
+    --exclude '.terraform*' \
+    --exclude 'dirs-archive-*' \
+    --exclude "$erlang_nodename@*" \
+    -T "$manifest" \
+    | xz --threads=0 > "$dirs_archive"
 
   rm "$manifest" "$sorted_manifest"
 }
@@ -122,11 +121,13 @@ start_vms() {
   terraform apply \
     -auto-approve=true \
     -var="erlang_version=$erlang_branch" \
+    -var="elixir_version=$elixir_version" \
     -var="erlang_cookie=$erlang_cookie" \
-    -var="erlang_nodename=control" \
+    -var="erlang_nodename=$erlang_nodename" \
     -var="ssh_key=$ssh_key" \
     -var="instance_count=$instance_count" \
-    -var='dirs_to_upload='"$dirs_to_upload" \
+    -var="instance_name_prefix=\"$instance_name_prefix\"" \
+    -var="upload_dirs_archive=$dirs_archive" \
     "$terraform_dir"
 }
 
@@ -134,11 +135,13 @@ destroy_vms() {
   terraform destroy \
     -force \
     -var="erlang_version=$erlang_branch" \
+    -var="elixir_version=$elixir_version" \
     -var="erlang_cookie=$erlang_cookie" \
-    -var="erlang_nodename=control" \
+    -var="erlang_nodename=$erlang_nodename" \
     -var="ssh_key=$ssh_key" \
     -var="instance_count=$instance_count" \
-    -var='dirs_to_upload='"$dirs_to_upload" \
+    -var="instance_name_prefix=\"$instance_name_prefix\"" \
+    -var="upload_dirs_archive=$dirs_archive" \
     "$terraform_dir"
 }
 
@@ -161,8 +164,8 @@ if test -z "$ssh_key" || ! test -f "$ssh_key" || ! test -f "$ssh_key.pub"; then
 fi
 
 erlang_cookie=$(cat ~/.erlang.cookie)
-dirs_to_upload=$(list_dirs_to_upload "$@")
 
+list_dirs_to_upload "$@"
 init_terraform
 
 case "$destroy" in

deps/rabbitmq_ct_helpers/tools/terraform/autoscaling-group/variables.tf

@@ -7,6 +7,13 @@ the underlying OS.
 EOF
 }
 
+variable "elixir_version" {
+  default     = ""
+  description = <<EOF
+Elixir version to deploy on VMs. Default to the latest available.
+EOF
+}
+
 variable "erlang_cookie" {
   description = <<EOF
 Erlang cookie to deploy on VMs.

deps/rabbitmq_ct_helpers/tools/terraform/direct-vms/main.tf

@@ -172,6 +172,7 @@ data "template_file" "user_data" {
     erlang_nodename  = "${var.erlang_nodename}"
     erlang_version   = "${var.erlang_version}"
     erlang_git_ref   = "${var.erlang_git_ref}"
+    elixir_version   = "${var.elixir_version}"
   }
 }
 

deps/rabbitmq_ct_helpers/tools/terraform/direct-vms/setup-vms.sh

@@ -4,12 +4,12 @@
 set -e
 
 usage() {
-  echo "Syntax: $(basename "$0") [-Dh] [-c <instance_count>] [-s <ssh_key>] <erlang_version> [<erlang_app_dir> ...]"
+  echo "Syntax: $(basename "$0") [-Dh] [-c <instance_count>] [-e <elixir_version>] [-s <ssh_key>] <erlang_version> [<erlang_app_dir> ...]"
 }
 
 instance_count=1
 
-while getopts "c:Dhs:" opt; do
+while getopts "c:e:Dhs:" opt; do
   case $opt in
     h)
       usage
@@ -18,6 +18,9 @@ while getopts "c:Dhs:" opt; do
     c)
       instance_count=$OPTARG
       ;;
+    e)
+      elixir_version=$OPTARG
+      ;;
     D)
       destroy=yes
       ;;
@@ -118,6 +121,7 @@ start_vms() {
   terraform apply \
     -auto-approve=true \
     -var="erlang_version=$erlang_branch" \
+    -var="elixir_version=$elixir_version" \
     -var="erlang_git_ref=$erlang_git_ref" \
     -var="erlang_cookie=$erlang_cookie" \
     -var="erlang_nodename=$erlang_nodename" \
@@ -132,6 +136,7 @@ destroy_vms() {
   terraform destroy \
     -force \
     -var="erlang_version=$erlang_branch" \
+    -var="elixir_version=$elixir_version" \
     -var="erlang_git_ref=$erlang_git_ref" \
     -var="erlang_cookie=$erlang_cookie" \
     -var="erlang_nodename=$erlang_nodename" \

deps/rabbitmq_ct_helpers/tools/terraform/direct-vms/templates/setup-erlang.sh

@@ -19,6 +19,8 @@ readonly erlang_version='${erlang_version}'
 # shellcheck disable=SC2016
 erlang_git_ref='${erlang_git_ref}'
 # shellcheck disable=SC2016
+readonly elixir_version='${elixir_version}'
+# shellcheck disable=SC2016
 readonly erlang_nodename='${erlang_nodename}'
 # shellcheck disable=SC2016
 readonly default_user='${default_user}'
@@ -67,6 +69,38 @@ EOF
 # Functions to take Erlang and Elixir from Debian packages.
 # --------------------------------------------------------------------
 
+determine_version_to_pin() {
+  package=$1
+  min_version=$2
+
+  apt-cache policy "$package" | \
+    awk '
+BEGIN {
+  version_to_pin = "";
+}
+/^ (   |\*\*\*) [^ ]/ {
+  if ($1 == "***") {
+    version = $2;
+  } else {
+    version = $1;
+  }
+
+  if (version_to_pin) {
+    exit;
+  } else if (match(version, /^'$min_version'([-.]|$)/)) {
+    version_to_pin = version;
+  }
+}
+END {
+  if (version_to_pin) {
+    print version_to_pin;
+    exit;
+  } else {
+    exit 1;
+  }
+}'
+}
+
 setup_erlang_deb_repository() {
   # Setup repository to get Erlang.
   readonly esl_package=/tmp/erlang-solutions_1.0_all.deb
@@ -89,6 +123,17 @@ apt_install_erlang() {
 }
 
 apt_install_elixir() {
+  if test "$elixir_version"; then
+    # Configure Elixir version pinning.
+    elixir_package_version=$(determine_version_to_pin elixir "$elixir_version")
+
+    cat >/etc/apt/preferences.d/elixir <<EOF
+Package: elixir
+Pin: version $elixir_package_version
+Pin-Priority: 1000
+EOF
+  fi
+
   case "$debian_codename" in
     wheezy)
       # We don't install Elixir because we only use Debian Wheezy to

deps/rabbitmq_ct_helpers/tools/terraform/direct-vms/variables.tf

@@ -15,6 +15,13 @@ version is still required.
 EOF
 }
 
+variable "elixir_version" {
+  default     = ""
+  description = <<EOF
+Elixir version to deploy on VMs. Default to the latest available.
+EOF
+}
+
 variable "erlang_cookie" {
   description = <<EOF
 Erlang cookie to deploy on VMs.