refactor mirror configuration

  - resolve and validate all mirror inputs (urls, gpg keys) in Mirrors.__init__
  - builder writes mirror artifacts instead of computing them
  - store buildcache, bootstrap and source_caches as separate members
  - decode gpg keys to in-memory bytes; expose config_files()/gpg_key_paths()
  - fix always-true magic gpg key check; reject non-key data
  - fix build cache mirror name mismatch in cache-force and --cache pushes
  - keep file:// urls as strings

Author: bcumming

docs/cluster-config.md

@@ -101,7 +101,7 @@ On air-gapped systems, Spack is unable to reach its default mirror to fetch pack
 
 `mirrors.yaml` may include source mirrors, bootstrap mirrors, and buildcaches. Any number of source mirrors can be added, but only one bootstrap mirror and buildcache can be specified. Spack will search the source mirrors in order from first to last, and will append the default Spack mirror to the bottom of the list when the Spack mirror config is generated.
 
-If using a buildcache, a private key must be provided for signing packages. An optional public key may be specified with any type of mirror to verify packages.
+If using a buildcache, a private key must be provided for signing packages. An optional public key may be specified with any type of mirror to verify packages. The buildcache is registered with Spack under the name `buildcache`, which can be overridden with an optional `name` field.
 
 To stop using a mirror, remove (or comment out) its entry from `mirrors.yaml`.
 

stackinator/builder.py

@@ -11,7 +11,7 @@
 import jinja2
 import yaml
 
-from . import VERSION, root_logger, spack_util, mirror
+from . import VERSION, root_logger, spack_util
 
 
 def install(src, dst, *, ignore=None, symlinks=False):
@@ -224,6 +224,15 @@ def generate(self, recipe):
             lstrip_blocks=True,
         )
 
+        # Write the spack mirror config artifacts (mirrors.yaml, bootstrap config,
+        # and the relocated gpg keys) into the config scope. These were fully
+        # resolved and validated by the recipe, so we just write the bytes. This
+        # must precede the Makefile render, which references the gpg key paths.
+        self._logger.debug(f"Writing the spack mirror configs to '{config_path}'")
+        for dest, content in recipe.mirrors.config_files(config_path).items():
+            dest.parent.mkdir(parents=True, exist_ok=True)
+            dest.write_bytes(content)
+
         # generate top level makefiles
         makefile_template = jinja_env.get_template("Makefile")
 
@@ -235,7 +244,7 @@ def generate(self, recipe):
                     pre_install_hook=recipe.pre_install_hook,
                     spack_version=spack_version,
                     spack_meta=spack_meta,
-                    gpg_keys=recipe.mirrors.keys,
+                    gpg_keys=recipe.mirrors.gpg_key_paths(config_path),
                     cache=recipe.build_cache_mirror,
                     exclude_from_cache=["nvhpc", "cuda", "perl"],
                     verbose=False,
@@ -314,14 +323,6 @@ def generate(self, recipe):
         with global_packages_path.open("w") as fid:
             fid.write(global_packages_yaml)
 
-        # generate a mirrors.yaml file if build caches have been configured
-        self._logger.debug(f"Generating the spack mirror configs in '{config_path}'")
-        try:
-            recipe.mirrors.setup_configs(config_path)
-        except mirror.MirrorError as err:
-            self._logger.error(f"Could not set up mirrors.\n{err}")
-            return 1
-
         # Add custom spack package recipes, configured via Spack repos.
         # Step 1: copy Spack repos to store_path where they will be used to
         #         build the stack, and then be part of the upstream provided