Restore missing find-job.sh script

This was incorrectly dropped with the old CI infrastructure.

ci/default.nix

@@ -72,6 +72,9 @@ let
             --set USE_NIX 1 \
             --set CI_CONFIG ${./config.sh}
 
+        makeWrapper ${./find-job.sh} $out/bin/find-job \
+            --prefix PATH : ${stdenv.lib.makeBinPath deps}:$out/bin
+
         makeWrapper ${xz}/bin/xz $out/bin/xz
       '';
 in

ci/find-job.sh

+#!/usr/bin/env bash
+
+set -e
+
+project_id=$1
+pipeline_id=$2
+job_name=$3
+
+# Access token is a protected environment variable in the head.hackage project and
+# is necessary for this query to succeed. Sadly job tokens only seem to
+# give us access to the project being built.
+curl \
+  --silent --show-error \
+  -H "Private-Token: $ACCESS_TOKEN" \
+  "https://gitlab.haskell.org/api/v4/projects/$project_id/pipelines/$pipeline_id/jobs?scope[]=success" \
+  > resp.json
+
+job_id=$(jq ". | map(select(.name == \"$job_name\")) | .[0].id" < resp.json)
+if [ "$job_id" = "null" ]; then
+  echo "Error finding job $job_name for $pipeline_id in project $project_id:" >&2
+  cat resp.json >&2
+  rm resp.json
+  exit 1
+else
+  rm resp.json
+  echo -n "$job_id"
+fi