Add jsonnet to build image (#6526)

* Add jsonnet to build image
Needed for https://github.com/grafana/loki/pull/6456

* Add pipeline step to build image

.drone/drone.jsonnet

@@ -388,11 +388,24 @@ local manifest_ecr(apps, archs) = pipeline('manifest-ecr') {
 
 [
   pipeline('loki-build-image') {
+    local build_image_tag = '0.22.0',
     workspace: {
       base: '/src',
       path: 'loki',
     },
     steps: [
+      {
+        name: 'test-image',
+        image: 'plugins/docker',
+        when: condition('exclude').tagMain + condition('include').path('loki-build-image/**'),
+        settings: {
+          repo: 'grafana/loki-build-image',
+          context: 'loki-build-image',
+          dockerfile: 'loki-build-image/Dockerfile',
+          tags: [build_image_tag],
+          dry_run: true,
+        },
+      },
       {
         name: 'push-image',
         image: 'plugins/docker',
@@ -403,7 +416,7 @@ local manifest_ecr(apps, archs) = pipeline('manifest-ecr') {
           dockerfile: 'loki-build-image/Dockerfile',
           username: { from_secret: docker_username_secret.name },
           password: { from_secret: docker_password_secret.name },
-          tags: ['0.21.0'],
+          tags: [build_image_tag],
           dry_run: false,
         },
       },

.drone/drone.yml

@@ -2,6 +2,24 @@
 kind: pipeline
 name: loki-build-image
 steps:
+- image: plugins/docker
+  name: test-image
+  settings:
+    context: loki-build-image
+    dockerfile: loki-build-image/Dockerfile
+    dry_run: true
+    repo: grafana/loki-build-image
+    tags:
+    - 0.22.0
+  when:
+    paths:
+      include:
+      - loki-build-image/**
+    ref:
+      exclude:
+      - refs/heads/main
+      - refs/heads/k???
+      - refs/tags/v*
 - image: plugins/docker
   name: push-image
   settings:
@@ -12,7 +30,7 @@ steps:
       from_secret: docker_password
     repo: grafana/loki-build-image
     tags:
-    - 0.21.0
+    - 0.22.0
     username:
       from_secret: docker_username
   when:
@@ -1313,6 +1331,6 @@ kind: secret
 name: deploy_config
 ---
 kind: signature
-hmac: e56633097c3edb68fc784f2059f5c773f02ac485750610aaff59b43eb1417c5b
+hmac: a81e5cc63bc5ef62ace94e345c1bba623f515741991cafb3386ebeb9b0a96989
 
 ...

loki-build-image/Dockerfile

@@ -66,7 +66,8 @@ RUN GO111MODULE=on go get github.com/goreleaser/nfpm/v2/cmd/nfpm@v2.11.3
 FROM golang:1.17.9 as jsonnet
 RUN GO111MODULE=on go get \
     github.com/jsonnet-bundler/jsonnet-bundler/cmd/jb@v0.4.0 \
-    github.com/monitoring-mixins/mixtool/cmd/mixtool@bca3066
+    github.com/monitoring-mixins/mixtool/cmd/mixtool@bca3066 \
+    github.com/google/go-jsonnet/cmd/jsonnet@v0.18.0
 
 FROM golang:1.17.9-buster
 RUN apt-get update && \
@@ -89,6 +90,7 @@ COPY --from=ghr /go/bin/ghr /usr/bin/ghr
 COPY --from=nfpm /go/bin/nfpm /usr/bin/nfpm
 COPY --from=jsonnet /go/bin/jb /usr/bin/jb
 COPY --from=jsonnet /go/bin/mixtool /usr/bin/mixtool
+COPY --from=jsonnet /go/bin/jsonnet /usr/bin/jsonnet
 
 # Install some necessary dependencies.
 # Forcing GO111MODULE=on is required to specify dependencies at specific versions using the go mod notation.