Gracefully shutdown the terraform process

Signed-off-by: ialidzhikov <i.alidjikov@gmail.com>

Dockerfile

@@ -34,5 +34,6 @@ COPY --from=builder /tmp/terraformer/terraform /bin/terraform
 COPY --from=builder /tmp/terraformer/terraform-provider* /terraform-providers/
 
 ADD ./terraform.sh /terraform.sh
+ADD ./terraformer.sh /terraformer.sh
 
-CMD exec /terraform.sh
+CMD exec /terraformer.sh

example/20-terraformer-validate-pod.yaml

@@ -25,9 +25,8 @@ spec:
     image: eu.gcr.io/gardener-project/gardener/terraformer:latest
     imagePullPolicy: IfNotPresent
     command:
-    - sh
-    - -c
-    - sh /terraform.sh validate
+    - /terraformer.sh
+    - validate
     env:
     - name: TF_STATE_CONFIG_MAP_NAME
       value: some-name.infra.tf-state

example/30-terraformer-apply-pod.yaml

@@ -25,9 +25,8 @@ spec:
     image: eu.gcr.io/gardener-project/gardener/terraformer:latest
     imagePullPolicy: IfNotPresent
     command:
-    - sh
-    - -c
-    - sh /terraform.sh apply 2>&1; [[ -f /success ]] && exit 0 || exit 1
+    - /terraformer.sh
+    - apply
     env:
     - name: TF_STATE_CONFIG_MAP_NAME
       value: some-name.infra.tf-state

example/40-terraformer-destroy-pod.yaml

@@ -25,9 +25,8 @@ spec:
     image: eu.gcr.io/gardener-project/gardener/terraformer:0.16.0
     imagePullPolicy: IfNotPresent
     command:
-    - sh
-    - -c
-    - sh /terraform.sh destroy 2>&1; [[ -f /success ]] && exit 0 || exit 1
+    - /terraformer.sh
+    - destroy
     env:
     - name: TF_STATE_CONFIG_MAP_NAME
       value: some-name.infra.tf-state

terraform.sh

@@ -72,6 +72,14 @@ function end_execution() {
   # Delete trap handler to avoid recursion
   trap - HUP QUIT PIPE INT TERM EXIT
 
+  if [ -n "$TF_PID" ] && kill -0 "$TF_PID" &>/dev/null; then
+    echo "$(date) Sending SIGTERM to terraform process $TF_PID."
+    kill -SIGTERM $TF_PID
+    echo "$(date) Waiting for terraform process $TF_PID to complete..."
+    wait $TF_PID
+    echo "$(date) Terraform process $TF_PID completed."
+  fi
+
   # check whether the terraform state has changed
   if [[ ! -f "$PATH_STATE_OUT" ]] || diff "$PATH_STATE_IN" "$PATH_STATE_OUT" 1> /dev/null; then # passes (returns 0) if there is no diff
     # indicate success (exit code gets lost as the surrounding command pipes this script through 'tee')
@@ -139,6 +147,9 @@ else
   # Install trap handler for proper cleanup, summary and result code
   trap "exit 100" HUP QUIT PIPE
   trap end_execution INT TERM EXIT
+
+  TF_PID=
+
   if [[ "$command" == "apply" ]]; then
     terraform \
       apply \
@@ -147,7 +158,9 @@ else
       -state="$PATH_STATE_IN" \
       -state-out="$PATH_STATE_OUT" \
       -var-file="$PATH_VARIABLES" \
-      /tf
+      /tf &
+    TF_PID=$!
+    wait $TF_PID
     exitcode=$?
   elif [[ "$command" == "destroy" ]]; then
     terraform \

terraformer.sh

@@ -0,0 +1,44 @@
+#!/bin/bash -u
+#
+# Copyright (c) 2020 SAP SE or an SAP affiliate company. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+function end_execution() {
+  # Delete trap handler to avoid recursion
+  trap - HUP QUIT PIPE INT TERM
+
+  if [ -n "$PID" ] && kill -0 "$PID" &>/dev/null; then
+    echo "$(date) Sending SIGTERM to terraform.sh process $PID."
+    kill -SIGTERM $PID
+    echo "$(date) Waiting for terraform.sh process $PID to complete..."
+    wait $PID
+    echo "$(date) terraform.sh process $PID completed."
+  fi
+}
+
+# determine command
+command="${1:-apply}"
+
+trap end_execution INT TERM
+
+PID=
+
+/terraform.sh "$command" 2>&1 &
+PID=$!
+wait $PID
+exitcode=$?
+
+echo "$(date) terraform.sh exited with $exitcode."
+
+[[ -f /success ]] && exit 0 || exit 1