Revert "Revert "gitlab: Add shared PR mirror to places pipelines look for binaries. (#33746)" (#34087)" (#34153)

This reverts commit 63e440651436fdc30993ef58875279e71f4851d1.

3 files changed, 17 insertions, 0 deletions

diff --git a/lib/spack/spack/ci.py b/lib/spack/spack/ci.py
index 43e7d03226..6dcfb7a7f3 100644
--- a/lib/spack/spack/ci.py
+++ b/lib/spack/spack/ci.py
@@ -49,6 +49,7 @@ JOB_RETRY_CONDITIONS = [
 
 TEMP_STORAGE_MIRROR_NAME = "ci_temporary_mirror"
 SPACK_RESERVED_TAGS = ["public", "protected", "notary"]
+SHARED_PR_MIRROR_URL = "s3://spack-binaries-prs/shared_pr_mirror"
 
 spack_gpg = spack.main.SpackCommand("gpg")
 spack_compiler = spack.main.SpackCommand("compiler")
@@ -729,6 +730,12 @@ def generate_gitlab_ci_yaml(
         # won't fetch its index and include in our local cache.
         spack.mirror.add("ci_pr_mirror", remote_mirror_override, cfg.default_modify_scope())
 
+    shared_pr_mirror = None
+    if spack_pipeline_type == "spack_pull_request":
+        stack_name = os.environ.get("SPACK_CI_STACK_NAME", "")
+        shared_pr_mirror = url_util.join(SHARED_PR_MIRROR_URL, stack_name)
+        spack.mirror.add("ci_shared_pr_mirror", shared_pr_mirror, cfg.default_modify_scope())
+
     pipeline_artifacts_dir = artifacts_root
     if not pipeline_artifacts_dir:
         proj_dir = os.environ.get("CI_PROJECT_DIR", os.getcwd())
@@ -803,6 +810,8 @@ def generate_gitlab_ci_yaml(
         # Clean up remote mirror override if enabled
         if remote_mirror_override:
             spack.mirror.remove("ci_pr_mirror", cfg.default_modify_scope())
+        if spack_pipeline_type == "spack_pull_request":
+            spack.mirror.remove("ci_shared_pr_mirror", cfg.default_modify_scope())
 
     all_job_names = []
     output_object = {}
@@ -1292,6 +1301,7 @@ def generate_gitlab_ci_yaml(
             "SPACK_LOCAL_MIRROR_DIR": rel_local_mirror_dir,
             "SPACK_PIPELINE_TYPE": str(spack_pipeline_type),
             "SPACK_CI_STACK_NAME": os.environ.get("SPACK_CI_STACK_NAME", "None"),
+            "SPACK_CI_SHARED_PR_MIRROR_URL": shared_pr_mirror or "None",
             "SPACK_REBUILD_CHECK_UP_TO_DATE": str(prune_dag),
             "SPACK_REBUILD_EVERYTHING": str(rebuild_everything),
         }
diff --git a/lib/spack/spack/cmd/ci.py b/lib/spack/spack/cmd/ci.py
index 5c3e03c59b..f82dbba4ae 100644
--- a/lib/spack/spack/cmd/ci.py
+++ b/lib/spack/spack/cmd/ci.py
@@ -284,6 +284,7 @@ def ci_rebuild(args):
     remote_mirror_override = get_env_var("SPACK_REMOTE_MIRROR_OVERRIDE")
     remote_mirror_url = get_env_var("SPACK_REMOTE_MIRROR_URL")
     spack_ci_stack_name = get_env_var("SPACK_CI_STACK_NAME")
+    shared_pr_mirror_url = get_env_var("SPACK_CI_SHARED_PR_MIRROR_URL")
     rebuild_everything = get_env_var("SPACK_REBUILD_EVERYTHING")
 
     # Construct absolute paths relative to current $CI_PROJECT_DIR
@@ -471,6 +472,10 @@ def ci_rebuild(args):
             spack.mirror.add("mirror_override", remote_mirror_override, cfg.default_modify_scope())
         pipeline_mirrors.append(remote_mirror_override)
 
+    if spack_pipeline_type == "spack_pull_request":
+        if shared_pr_mirror_url != "None":
+            pipeline_mirrors.append(shared_pr_mirror_url)
+
     matches = (
         None
         if full_rebuild
diff --git a/lib/spack/spack/test/cmd/ci.py b/lib/spack/spack/test/cmd/ci.py
index 796bf5420f..640ef0d236 100644
--- a/lib/spack/spack/test/cmd/ci.py
+++ b/lib/spack/spack/test/cmd/ci.py
@@ -706,6 +706,8 @@ spack:
 """
         )
 
+    monkeypatch.setattr(spack.ci, "SHARED_PR_MIRROR_URL", "https://fake.shared.pr.mirror")
+
     with tmpdir.as_cwd():
         env_cmd("create", "test", "./spack.yaml")
         outputfile = str(tmpdir.join(".gitlab-ci.yml"))