fix mount_specific behavior; remove "enabled" toggle

always pass the mount when creating Mirrors
- the choice about whether to use a mount-specific url for the build
  cache is decided using the mount_specific boolean flag

the "enabled" boolean flag for turning caches on and off was redundant
- the mirrors.yaml file describes the mirrors to use
- mirrors.yaml will typically be a static file injected into pipelines,
  and the only use case where you might want to modify its behavior is
when doing manual testing - in which case comment out.
flipping a switch.
- if we want, we can add CLI flags for turning mirror selection.

Author: bcumming

CLAUDE.md

@@ -0,0 +1,329 @@
+# Stackinator
+
+Stackinator is a Python CLI tool that generates build configurations for scientific software stacks on HPE Cray EX (Alps) systems. It acts like `cmake`/`configure`: given a **recipe** and a **cluster configuration**, it produces a build directory with Makefiles and Spack YAML files. The actual build is then performed by `make`.
+
+## Two-Phase Workflow
+
+```
+stack-config -b BUILD -r RECIPE -s SYSTEM [-c CACHE] [-m MOUNT]
+    → generates BUILD/ directory with Makefiles + spack.yaml files
+
+cd BUILD
+env --ignore-environment PATH=/usr/bin:/bin:`pwd -P`/spack/bin make store.squashfs -j64
+    → clones Spack, concretises, builds, creates store.squashfs
+```
+
+The `store.squashfs` SquashFS image is the final artifact, intended to be mounted at the recipe's `store` path (default `/user-environment`) as a uenv image.
+
+## Repository Layout
+
+```
+stackinator/           # Python package
+  main.py              # CLI entry point (stack-config)
+  recipe.py            # Recipe class: parses and validates all recipe YAML
+  builder.py           # Builder class: writes all files to the build path
+  cache.py             # Build cache configuration helpers
+  spack_util.py        # Tiny helper: checks if a path is a spack package repo
+  schema.py            # JSON schema validators with default-injection
+  schema/              # JSON schemas for each YAML file type
+    config.json
+    compilers.json
+    environments.json
+    cache.json
+    modules.json
+  templates/           # Jinja2 templates for all generated files
+    Makefile            # Top-level build orchestration
+    Makefile.compilers  # Compiler build steps
+    Makefile.environments # Environment build + view generation steps
+    Makefile.generate-config # Generates upstream spack config for the uenv
+    Make.user           # Build path / store / sandbox variable definitions
+    repos.yaml          # Generated spack repos.yaml
+    stack-debug.sh      # Debug helper script
+    compilers.*.spack.yaml  # Per-compiler spack.yaml configs
+    environments.spack.yaml # Environment spack.yaml config
+  etc/
+    Make.inc            # Shared make rules (concretize, depfile, compiler_bin_dirs)
+    bwrap-mutable-root.sh  # Bubblewrap sandbox wrapper
+    envvars.py          # CLI tool: generates env.json for views and uenv metadata
+docs/                  # MkDocs documentation source
+unittests/             # pytest test suite
+  test_schema.py        # Schema validation tests (primary test coverage)
+  recipes/              # Example recipes used by tests
+  yaml/                 # Example YAML snippets for testing
+```
+
+## Recipe Format (input)
+
+A recipe is a directory containing YAML files:
+
+### `config.yaml` (required)
+```yaml
+name: prgenv-gnu
+store: /user-environment        # mount point; default /user-environment
+version: 2                      # must be 2 for Spack 1.0 (Stackinator 6+)
+spack:
+  repo: https://github.com/spack/spack.git
+  commit: releases/v1.0         # branch, tag, or SHA; null = default branch
+  packages:
+    repo: https://github.com/spack/spack-packages.git
+    commit: develop
+description: "optional text"
+default-view: develop           # optional: view loaded when no view is specified
+```
+
+- `version: 1` (the default) targets Spack v0.23 and is only supported by Stackinator v5 (`releases/v5` branch). **Current `main` requires `version: 2`.**
+- `store` can be overridden at configure time with `-m/--mount`.
+
+### `compilers.yaml` (required)
+```yaml
+gcc:
+  version: "13"          # required; must be quoted string
+nvhpc:                   # optional
+  version: "25.1"
+llvm:                    # optional
+  version: "16"
+llvm-amdgpu:             # optional
+  version: "6.0"
+intel-oneapi-compilers:  # optional
+  version: "2024.1"
+```
+
+Build order: `gcc` is built first (using system compiler), then `nvhpc`/`llvm`/`llvm-amdgpu`/`intel-oneapi-compilers` are built using the gcc toolchain. Stackinator appends opinionated variants (e.g. `gcc@13 +bootstrap`, `nvhpc@25.1 ~mpi~blas~lapack`, `llvm@16 +clang ~gold`).
+
+### `environments.yaml` (required)
+```yaml
+my-env:
+  compiler: [gcc]               # required; list from compilers.yaml keys; first = default
+  specs:                        # required; list of spack specs
+    - cmake
+    - hdf5+mpi
+  network:                      # optional; null = no MPI
+    mpi: cray-mpich             # full spack spec for MPI (cray-mpich or openmpi)
+    specs: ['libfabric@1.22']   # optional; overrides network.yaml defaults
+  unify: true                   # concretizer: true | false | when_possible (default true)
+  duplicates:
+    strategy: minimal           # minimal | full | none (default minimal)
+  deprecated: false             # allow deprecated spack versions (default false)
+  variants:                     # applied to all packages (packages:all:variants)
+    - +cuda
+    - cuda_arch=80
+  prefer: null                  # packages:all:prefer; auto-set if null
+  packages:                     # external packages to discover via `spack external find`
+    - perl
+    - git
+  views:                        # optional filesystem views
+    default: null               # view name → view config (null = defaults)
+    no-python:
+      exclude: [python]
+      uenv:
+        add_compilers: true     # default true; adds compiler symlinks to view/bin
+        prefix_paths:
+          LD_LIBRARY_PATH: [lib, lib64]
+        env_vars:
+          set:
+            - MYVAR: "value"
+            - MYVAR2: null      # unsets the variable
+          prepend_path:
+            - PATH: "/some/path"
+          append_path:
+            - PKG_CONFIG_PATH: "/usr/lib/pkgconfig"
+```
+
+**Key constraints:**
+- Do not include MPI or compilers in `specs`; they are handled by `network.mpi` and `compiler`.
+- Spec matrices are not supported.
+- Only one MPI per environment; create separate environments for multiple MPIs.
+- The `prefer` field is auto-generated if `null`: it nudges Spack to use the first compiler for all packages.
+
+#### Environment variable special syntax
+- `${@VAR@}` — deferred expansion: expands `VAR` at uenv load time (e.g. `${@HOME@}`)
+- `$@key@` — substitution at configure time: `mount`, `view_name`, `view_path`
+
+#### Supported prefix-path variables (hardcoded in `etc/envvars.py`)
+`ACLOCAL_PATH`, `CMAKE_PREFIX_PATH`, `CPATH`, `LD_LIBRARY_PATH`, `LIBRARY_PATH`, `MANPATH`, `MODULEPATH`, `PATH`, `PKG_CONFIG_PATH`, `PYTHONPATH`
+
+### `modules.yaml` (optional)
+Presence of this file enables module generation. Follows Spack's module config format with two differences:
+- `modules:default:arch_folder` must be `false` (Stackinator doesn't support `true`)
+- `modules:default:roots:tcl` is ignored and overwritten by Stackinator
+
+### `packages.yaml` (optional)
+Standard Spack `packages.yaml` with recipe-specific external package overrides.
+
+### `repo/` (optional)
+Custom Spack package definitions. Must contain a `packages/` subdirectory.
+Merged into a single `alps` namespace repo alongside system and site packages.
+Precedence: recipe repo > site repos (from cluster config `repos.yaml`) > Spack builtin.
+
+### `post-install` / `pre-install` (optional)
+Shell scripts (any language) run inside the bwrap sandbox:
+- `pre-install`: after Spack is set up, before first compiler build
+- `post-install`: after all packages are built, before squashfs generation
+
+Both are Jinja-templated with variables: `env.mount`, `env.config`, `env.build`, `env.spack`.
+
+### `extra/` (optional)
+Arbitrary files copied to `meta/extra/` in the final image (used for CI metadata).
+
+## Cluster Configuration (input)
+
+A directory (passed via `-s/--system`) containing:
+
+```
+cluster-config/
+  packages.yaml   # Spack external packages; must include gcc
+  network.yaml    # MPI defaults and network library package configs
+  repos.yaml      # optional; list of relative paths to site-wide spack repos
+```
+
+`network.yaml` structure:
+```yaml
+mpi:
+  cray-mpich:
+    specs: [libfabric@1.22]   # default specs injected when cray-mpich is chosen
+  openmpi:
+    specs: [libfabric@2.2.0]
+packages:                     # standard spack packages.yaml content
+  libfabric: ...
+  cray-mpich: ...
+```
+
+Package precedence (recipe.py merges these): recipe `packages.yaml` > `network.yaml` packages > `packages.yaml` (minus gcc). The `gcc` entry from `packages.yaml` is isolated and used only for the gcc compiler build step.
+
+## Build Directory Structure (output)
+
+```
+BUILD/
+  Makefile              # top-level orchestration
+  Make.user             # variables: BUILD_ROOT, STORE, SANDBOX, etc.
+  Make.inc              # shared make rules (copied from etc/)
+  bwrap-mutable-root.sh # sandbox wrapper (copied from etc/)
+  envvars.py            # view/meta generator (copied from etc/)
+  spack/                # cloned Spack repository
+  spack-packages/       # cloned spack-packages repository
+  config/               # global spack configuration scope
+    packages.yaml
+    mirrors.yaml        # only if --cache provided
+    repos.yaml
+  compilers/
+    Makefile
+    gcc/
+      spack.yaml
+      packages.yaml     # generated by spack external find
+    nvhpc/              # if nvhpc in recipe
+      spack.yaml
+  environments/
+    Makefile
+    my-env/
+      spack.yaml
+  generate-config/      # generates the upstream spack config for the final image
+    Makefile
+  modules/              # only if modules.yaml in recipe
+    modules.yaml
+  store/                # installation root (bind-mounted to recipe.store during build)
+    meta/
+      configure.json    # build metadata
+      env.json.in       # view metadata template
+      recipe/           # copy of the recipe
+    repos/spack_repo/alps/   # consolidated custom package repo
+    repos/spack_repo/builtin/ # copy of spack builtin repo
+    env/                # filesystem views (created during build)
+      view-name/
+        activate.sh
+        env.json
+        bin/ lib/ ...
+  store.squashfs        # final compressed image
+  stack-debug.sh        # debug helper: opens shell in build environment
+```
+
+## Python Architecture
+
+### `Recipe` class (`recipe.py`)
+Parses and validates all recipe inputs in `__init__`. Key responsibilities:
+- Validates each YAML file against its JSON schema (with default injection)
+- Merges packages from cluster config, network.yaml, and recipe
+- Generates full compiler specs (e.g. `gcc@13 +bootstrap`) from `compilers.yaml`
+- Processes environments: resolves MPI specs from `network.yaml` templates, sets default `prefer` constraints, builds view metadata
+- Provides `compiler_files` and `environment_files` properties (Jinja-rendered Makefiles and spack.yaml files)
+
+### `Builder` class (`builder.py`)
+Writes all files to the build path. Key responsibilities:
+- Creates directory structure
+- Clones Spack and spack-packages repositories
+- Merges and writes the consolidated `alps` spack package repo
+- Renders all Jinja templates into build path files
+- Writes metadata JSON files
+
+### `schema.py`
+JSON schema validation using `jsonschema`. The `validator()` function extends the validator to auto-inject `default` values from schemas into parsed instances, so downstream code can rely on optional fields always being present.
+
+### `etc/envvars.py`
+A standalone CLI tool (copied into the build directory) with two subcommands:
+- `envvars.py view <root> <build_path> [--compilers] [--prefix_paths]`: reads a Spack-generated `activate.sh`, parses env vars, adds compiler symlinks and prefix paths, writes `env.json` for the view
+- `envvars.py uenv <mount> [--modules] [--spack]`: merges view `env.json` files with recipe `env_vars` config, writes the final `meta/env.json`
+
+The `EnvVarSet` class in `envvars.py` is also imported by `recipe.py` for processing `env_vars` at configure time.
+
+## Build Pipeline (Make targets)
+
+The top-level `Makefile` orchestrates in order:
+1. `spack-setup` — sanity check, bootstrap concretizer
+2. `pre-install` — run `pre-install-hook` if provided
+3. `mirror-setup` — configure build cache keys
+4. `compilers` — build gcc, then nvhpc/llvm/etc. (parallel within each stage)
+5. `environments` — build all user environments (parallel)
+6. `generate-config` — generate the upstream spack config files for the installed image
+7. `modules-done` — generate TCL module files (if `modules.yaml` present)
+8. `env-meta` — run `envvars.py uenv` to produce final `meta/env.json`
+9. `post-install` — run `post-install-hook` if provided
+10. `store.squashfs` — create the final squashfs image
+
+Key Make.inc rules:
+- `%/spack.lock`: concretize a spack environment
+- `%/Makefile`: generate a depfile from a lock file (enables parallel package builds)
+- `compiler_bin_dirs`: helper to find compiler binaries given install prefixes
+
+The build runs inside a bwrap sandbox (`bwrap-mutable-root.sh`) that:
+- Bind-mounts `BUILD/store` → `STORE` (the recipe mount point)
+- Bind-mounts `BUILD/tmp` → `/tmp`
+- Puts a tmpfs over `$HOME` (isolates user config)
+
+## Build Cache
+
+Optional binary cache configured via YAML file passed to `-c/--cache`:
+```yaml
+root: /path/to/cache       # directory; env vars expanded
+key: /path/to/pgp.key      # optional; omit for read-only cache
+```
+
+Cache is stored in a subdirectory named after the mount point (e.g. `cache/user-environment/`) to avoid relocation issues. Packages are pushed per-environment after a successful build. Large binary packages (`cuda`, `nvhpc`, `perl`) are excluded from cache pushes.
+
+## Testing
+
+```bash
+uv run pytest            # run tests
+./lint                   # ruff format + ruff check --fix
+```
+
+Tests live in `unittests/test_schema.py` and cover schema validation and default injection. Test recipes are in `unittests/recipes/`, example YAML in `unittests/yaml/`.
+
+The test coverage is limited — the schema validators and their default-injection are well tested, but `Recipe`, `Builder`, and `envvars.py` have minimal test coverage.
+
+## Code Style
+
+- Python 3.12+
+- Linting: `ruff` (line length 120, E + F rules, E203 ignored)
+- Format: `ruff format`
+- Run both via `./lint`
+
+## Key Invariants and Pitfalls
+
+- **Build path restrictions**: cannot be in `/tmp`, `$HOME`, or root `/`. The bwrap sandbox rebinds these.
+- **Version 2 is required**: `config.yaml` must have `version: 2` for current `main`. Version 1 recipes require the `releases/v5` branch.
+- **gcc is required**: `packages.yaml` in cluster config must define an external `gcc`. It is handled separately from other system packages for the bootstrap build step.
+- **MPI validation**: the MPI name in `network.mpi` must match a key in `network.yaml:mpi` templates from the cluster config. Unknown MPI implementations raise an error.
+- **View names are globally unique**: view names must be unique across all environments in a recipe.
+- **`mirrors.yaml` in recipes is unsupported**: use `--cache` CLI flag instead.
+- **`default-view` must exist**: if set in `config.yaml`, the named view must be defined in `environments.yaml` (or be `modules`/`spack`).
+- **`prefer` is auto-set**: if `null` in the recipe, Stackinator generates a `prefer` constraint using Spack's `%[when=...]` syntax to pin the default compiler.
+- **Spack `uenv_tools` environment**: an internal environment named `uenv_tools` is injected into every build to install `squashfs`. Recipe authors must not use this name.

bin/stack-config

@@ -2,7 +2,6 @@
 # /// script
 # requires-python = ">=3.12"
 # dependencies = [
-#   "requests",
 #   "python-magic",
 #   "jinja2",
 #   "jsonschema",

docs/cluster-config.md

@@ -103,22 +103,20 @@ On air-gapped systems, Spack is unable to reach its default mirror to fetch pack
 
 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.
 
+To stop using a mirror, remove (or comment out) its entry from `mirrors.yaml`.
+
 ```yaml title="mirrors.yaml"
 bootstrap:
   url: file:///home/username/spack-mirror-2014-06-24
-  enabled: true
 buildcache:
   url: https://example.com/some/buildcache/mirror
-  enabled: true
   private_key: /user-home/.gnupg/private-keys-v1.d/my-private-key.asc
 sourcecache:
   mirror1:
     url: https://example.com/some/web-hosted/directory
     public_key: ../buildcache-key.public.gpg
-    enabled: true
   mirror2:
     url: https://example.com/some/other-web-hosted/directory
-    enabled: true
 ```
 
 ## Site and System Configurations

pyproject.toml

@@ -11,7 +11,6 @@ license-files = ["LICENSE"]
 dynamic = ["version"]
 requires-python = ">=3.12"
 dependencies = [
-  "requests",
   "python-magic",
   "Jinja2",
   "jsonschema",