feat: Add sigterm handler sample

run/sigterm-handler/.dockerignore

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+# The .dockerignore file excludes files from the container build process.
+#
+# https://docs.docker.com/engine/reference/builder/#dockerignore-file
+
+# Exclude locally vendored dependencies.
+vendor/
+
+# Exclude "build-time" ignore files.
+.dockerignore
+.gcloudignore
+
+# Exclude git history and configuration.
+.gitignore

run/sigterm-handler/.gcloudignore

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+# The .gcloudignore file excludes file from upload to Cloud Build.
+# If this file is deleted, gcloud will default to .gitignore.
+#
+# https://cloud.google.com/cloud-build/docs/speeding-up-builds#gcloudignore
+# https://cloud.google.com/sdk/gcloud/reference/topic/gcloudignore
+
+# Exclude locally vendored dependencies.
+vendor/
+
+# Exclude git history and configuration.
+.git/
+.gitignore

run/sigterm-handler/Dockerfile

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+# Copyright 2021 Google LLC
+#
+# 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
+#
+#    https://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.
+
+# Use the offical golang image to create a binary.
+# This is based on Debian and sets the GOPATH to /go.
+# https://hub.docker.com/_/golang
+FROM golang:1.15-buster as builder
+
+# Create and change to the app directory.
+WORKDIR /app
+
+# Retrieve application dependencies.
+# This allows the container build to reuse cached dependencies.
+# Expecting to copy go.mod and if present go.sum.
+COPY go.* ./
+RUN go mod download
+
+# Copy local code to the container image.
+COPY . ./
+
+# Build the binary.
+RUN go build -mod=readonly -v -o server
+
+# Use the official Debian slim image for a lean production container.
+# https://hub.docker.com/_/debian
+# https://docs.docker.com/develop/develop-images/multistage-build/#use-multi-stage-builds
+FROM debian:buster-slim
+RUN set -x && apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
+    ca-certificates && \
+    rm -rf /var/lib/apt/lists/*
+
+# Copy the binary to the production image from the builder stage.
+COPY --from=builder /app/server /app/server
+
+# Run the web service on container startup.
+CMD ["/app/server"]

run/sigterm-handler/go.mod

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+module github.com/GoogleCloudPlatform/golang-samples/run/sigterm-handler
+
+go 1.13

run/sigterm-handler/main.go

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+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+// Sample run-helloworld is a minimal Cloud Run service.
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"os/signal"
+	"syscall"
+)
+
+func main() {
+	go signalHandler()
+
+	log.Print("starting server...")
+	http.HandleFunc("/", handler)
+
+	// Determine port for HTTP service.
+	port := os.Getenv("PORT")
+	if port == "" {
+		port = "8080"
+		log.Printf("defaulting to port %s", port)
+	}
+
+	// Start HTTP server.
+	log.Printf("listening on port %s", port)
+	if err := http.ListenAndServe(":"+port, nil); err != nil {
+		log.Fatal(err)
+	}
+}
+
+// [START cloudrun_sigterm_handler]
+func signalHandler() {
+	signalChan := make(chan os.Signal, 1)
+	signal.Notify(signalChan, syscall.SIGINT, syscall.SIGTERM)
+
+	sig := <-signalChan
+	log.Printf("%s signal caught.", sig)
+	os.Exit(0)
+}
+
+// [END cloudrun_sigterm_handler]
+
+func handler(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprint(w, "Hello World!\n")
+}

run/sigterm-handler/main_test.go

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+// Copyright 2021 Google LLC
+//
+// 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
+//
+//     https://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.
+
+package main
+
+import (
+	"net/http/httptest"
+	"testing"
+)
+
+func TestHandler(t *testing.T) {
+	req := httptest.NewRequest("GET", "/", nil)
+	rr := httptest.NewRecorder()
+	handler(rr, req)
+
+	if got := rr.Body.String(); got != "Hello World!\n" {
+		t.Errorf("got %q, want %q", got, "Hello World!\n")
+	}
+}