optimize dockerfile

Bumps alpine from 3.18.5 to 3.19.0.

---
updated-dependencies:
- dependency-name: alpine
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/integration.yml

@@ -15,7 +15,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version: "1.19.x"
 
@@ -44,7 +44,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version: "1.19.x"
 

.github/workflows/release.yml

@@ -13,7 +13,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Setup go
-        uses: actions/setup-go@v4
+        uses: actions/setup-go@v5
         with:
           go-version: "1.19.x"
 

Dockerfile

@@ -1,30 +1,30 @@
-FROM alpine:3.18.4 as builder
+# syntax=docker/dockerfile:1
 
-WORKDIR /go/src/github.com/systemli/prometheus-mastodon-exporter
+# Build the application from source
+FROM golang:1.21.4 AS build-stage
 
-ENV USER=appuser
+WORKDIR /app
-ENV UID=10001
 
-RUN adduser \
+COPY go.mod go.sum ./
-    --disabled-password \
+RUN go mod download
-    --gecos "" \
-    --home "/nonexistent" \
-    --shell "/sbin/nologin" \
-    --no-create-home \
-    --uid "${UID}" \
-    "${USER}"
 
-RUN apk add --no-cache --update ca-certificates
+COPY *.go ./
 
-FROM scratch
+RUN CGO_ENABLED=0 GOOS=linux go build -o /prometheus-mastodon-exporter
 
-COPY --from=builder /etc/passwd /etc/passwd
+# Run the tests in the container
-COPY --from=builder /etc/group /etc/group
+FROM build-stage AS run-test-stage
-COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
+RUN go test -v ./...
-COPY prometheus-mastodon-exporter /prometheus-mastodon-exporter
 
-USER appuser:appuser
+# Deploy the application binary into a lean image
+FROM gcr.io/distroless/base-debian11 AS build-release-stage
+
+WORKDIR /
+
+COPY --from=build-stage /prometheus-mastodon-exporter /prometheus-mastodon-exporter
 
 EXPOSE 13120
 
+USER nonroot:nonroot
+
 ENTRYPOINT ["/prometheus-mastodon-exporter"]