ci: bump envoy-filter-example SHA on master merge. (envoyproxy#3106)

Signed-off-by: Harvey Tuch <[email protected]>

.circleci/config.yml

@@ -49,6 +49,17 @@ jobs:
            fingerprints:
              - "fb:f3:fe:be:1c:b2:ec:b6:25:f9:7b:a6:87:54:02:8c"
        - run: ci/api_mirror.sh
+   filter_example_mirror:
+     docker:
+       - image: *envoy-build-image
+     resource_class: xlarge
+     working_directory: /source
+     steps:
+       - checkout
+       - add_ssh_keys:
+           fingerprints:
+             - "f6:f9:df:90:9c:4b:5f:9c:f4:69:fd:42:94:ff:88:24"
+       - run: ci/filter_example_mirror.sh
    ipv6_tests:
      machine: true
      steps:
@@ -136,6 +147,7 @@ workflows:
       - asan
       - tsan
       - api
+      - filter_example_mirror
       - ipv6_tests
       - coverage
       - format

ci/filter_example_mirror.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+
+set -e
+
+CHECKOUT_DIR=../envoy-filter-example
+
+if [ -z "$CIRCLE_PULL_REQUEST" ] && [ "$CIRCLE_BRANCH" == "master" ]
+then
+  echo "Cloning..."
+  git clone [email protected]:envoyproxy/envoy-filter-example "$CHECKOUT_DIR"
+
+  git -C "$CHECKOUT_DIR" config user.name "envoy-filter-example(CircleCI)"
+  git -C "$CHECKOUT_DIR" config user.email [email protected]
+  git -C "$CHECKOUT_DIR" fetch
+  git -C "$CHECKOUT_DIR" checkout -B master origin/master
+
+  # Update submodule to latest Envoy SHA
+  ENVOY_SHA=$(git rev-parse HEAD)
+  git -C "$CHECKOUT_DIR" submodule update --init
+  git -C "$CHECKOUT_DIR/envoy" checkout "$ENVOY_SHA"
+  git -C "$CHECKOUT_DIR" commit -a -m "Update Envoy submodule to $ENVOY_SHA"
+
+  echo "Pushing..."
+  git -C "$CHECKOUT_DIR" push origin master
+  echo "Done"
+fi