Switch buildkite hooks to pipeline steps

This is a more explicit approach that can be applied to the PR pipeline
only and allows to run only once before/after the build, as opposed to
the pre/post command hooks that run for every command.

Author: nkammah

.buildkite/build_pr_pipeline.yml

@@ -1,7 +1,18 @@
 steps:
-  - label: ":white_check_mark: Build docs PR"
-    command: |
-      bash .buildkite/scripts/build_pr.sh
+  - key: "build-pr-setup"
+    label: "setup"
+    command: .buildkite/scripts/build_pr_setup.sh
+  - key: "build-pr"
+    label: ":hammer: Build docs PR"
+    command: .buildkite/scripts/build_pr.sh
+    depends_on:
+      - step: build-pr-setup
+        allow_failure: true
     agents:
       provider: "gcp"
       image: family/docs-ubuntu-2204
+  - command: .buildkite/scripts/build_pr_teardown.sh
+    label: "teardown"
+    depends_on:
+      - step: "build-pr"
+        allow_failure: true

.buildkite/hooks/pre-command renamed to .buildkite/scripts/build_pr_setup.sh

@@ -16,7 +16,7 @@ fi
 gitHubToken=$(vault read -field=value secret/ci/elastic-docs/docs_preview_cleaner)
 
 githubPublishStatus="https://api.github.com/repos/${GITHUB_PR_OWNER}/${GITHUB_PR_REPO}/statuses/${GITHUB_PR_TRIGGERED_SHA}"
-data='{"state":"pending","target_url":"'$BUILDKITE_BUILD_URL'","description":"Build started.","context":"buildkite/docs"}'
+data='{"state":"pending","target_url":"'$BUILDKITE_BUILD_URL'","description":"Build started.","context":"buildkite/'$BUILDKITE_PIPELINE_SLUG'"}'
 echo "Setting buildkite/docs commit status to pending"
 curl -s -L \
   -X POST \

.buildkite/hooks/post-command renamed to .buildkite/scripts/build_pr_teardown.sh

@@ -9,14 +9,14 @@ fi
 
 gitHubToken=$(vault read -field=value secret/ci/elastic-docs/docs_preview_cleaner)
 
-if [ -n "$BUILDKITE_COMMAND_EXIT_STATUS" ] && [ "$BUILDKITE_COMMAND_EXIT_STATUS" -eq "0" ];then
+if [ $(buildkite-agent step get "outcome" --step "build-pr") == "passed" ]; then
   status_state="success"
 else
   status_state="failure"
 fi
 
 githubPublishStatus="https://api.github.com/repos/${GITHUB_PR_OWNER}/${GITHUB_PR_REPO}/statuses/${GITHUB_PR_TRIGGERED_SHA}"
-data='{"state":"'$status_state'","target_url":"'$BUILDKITE_BUILD_URL'","description":"Build finished.","context":"buildkite/docs"}'
+data='{"state":"'$status_state'","target_url":"'$BUILDKITE_BUILD_URL'","description":"Build finished.","context":"buildkite/'$BUILDKITE_PIPELINE_SLUG'"}'
 echo "Setting buildkite/docs commit status to ${status_state}"
 curl -s -L \
   -X POST \