Unify build process, add golangci-lint

Signed-off-by: Knut Ahlers <knut@ahlers.me>

Dockerfile

@@ -7,14 +7,7 @@ COPY build.sh /usr/local/bin/
 RUN set -ex \
  && apk --no-cache add \
       bash \
-      ca-certificates \
-      curl \
-      docker \
-      git \
-      jq \
-      make \
- && /usr/local/bin/build.sh \
- && apk --no-cache del --purge jq
+ && /usr/local/bin/build.sh
 
 ENTRYPOINT ["/usr/local/bin/inner-runner"]
 CMD ["--"]

build.sh

@@ -1,8 +1,37 @@
 #!/bin/bash
 set -euxo pipefail
 
+# Packages required to build the image
+pkg_build=(
+	jq
+	tar
+)
+
+# Packages kept for the final image
+pkg_img=(
+	bash
+	ca-certificates
+	curl
+	docker
+	git
+	make
+)
+
+# Install required packages
+apk --no-cache add "${pkg_build[@]}" "${pkg_img[@]}"
+
+function get_asset_url() {
+	curl -sSfL "https://api.github.com/repos/${1}/releases/latest" |
+		jq -r '.assets | .[] | .browser_download_url' |
+		grep -E 'linux.*amd64'
+}
+
 # Download latest release of inner-runner
-DOWNLOAD=$(curl -sSfL https://api.github.com/repos/repo-runner/repo-runner/releases/latest |
-	jq -r '.assets | .[] | select(.name == "inner-runner_linux_amd64.tar.gz") | .browser_download_url')
-curl -sSfL "${DOWNLOAD}" | tar -xzf - -C /usr/local/bin
+curl -sSfL "$(get_asset_url repo-runner/repo-runner | grep inner-runner)" | tar -xzf - -C /usr/local/bin
 mv /usr/local/bin/inner-runner* /usr/local/bin/inner-runner
+
+# Download latest release of golangci-lint
+curl -sSfL "$(get_asset_url golangci/golangci-lint)" | tar -xzf - -C /usr/local/bin --wildcards '*/golangci-lint' --strip-components=1
+
+# Purge build-packages
+apk --no-cache del --purge "${pkg_build[@]}"