computer-playbook/docs/contributing/environment/cache.md

# Local Caches 📦

Three local cache services accelerate re-deploys, reduce upstream traffic, and harden the development workflow against transient upstream outages. They share one compose profile (`cache`) and one override file ([compose/cache.override.yml](../../../compose/cache.override.yml)) and are gated together by [profile.py](../../../cli/administration/deploy/development/profile.py): active on developer machines, inactive on CI runners.

## Services 🧩

### Registry Cache 🐳

[`registry-cache`](../../../compose/registry-cache/README.md) runs `rpardini/docker-registry-proxy` and transparently MITMs every Docker image pull from the inner `dockerd`, regardless of upstream registry (`docker.io`, `ghcr.io`, `mcr.microsoft.com`, …). The runner trusts the proxy CA via [registry-ca.sh](../../../scripts/docker/cache/registry-ca.sh).

Pulls only. Pushes are not intercepted.

### Package Cache 📚

[`package-cache`](../../../compose/package-cache/README.md) runs `sonatype/nexus3` and exposes pull-through proxies for package-manager downloads:

| Format | Repo names | Upstream |
|---|---|---|
| `apt` | `apt-debian`, `apt-debian-security`, `apt-ubuntu`, `apt-ubuntu-security` | `deb.debian.org`; both Ubuntu repos take the first entry of `INFINITO_APT_UBUNTU_MIRRORS` |
| `apt` (mirrors) | `apt-debian-mirror`, `apt-debian-security-mirror`, `apt-ubuntu-mirror`, `apt-ubuntu-security-mirror` | `ftp.debian.org`, `security.debian.org`; both Ubuntu repos take the second entry of `INFINITO_APT_UBUNTU_MIRRORS` |
| `pypi` | `pypi-proxy` | `pypi.org` (incl. `files.pythonhosted.org`) |
| `npm` | `npm-proxy` | `registry.npmjs.org` |
| `rubygems` | `gem-proxy` | `rubygems.org` |
| `go` | `go-proxy` | `proxy.golang.org` |
| `helm` | `helm-bitnami` | `charts.bitnami.com/bitnami` |
| `yum` | `yum-rocky`, `yum-fedora` | `download.rockylinux.org`, `download.fedoraproject.org` |
| `raw` | `raw-githubusercontent`, `raw-codeload-github`, `raw-packagist`, `raw-alpine` | `raw.githubusercontent.com`, `codeload.github.com`, `repo.packagist.org`, `dl-cdn.alpinelinux.org` |

A proxy repo that holds a cached copy serves it when its remote is unreachable, regardless of `metadataMaxAge` (measured). `autoBlock` is therefore off: while a remote is auto-blocked Nexus answers `404 Remote Auto Blocked` instead of falling back to that cached copy. The mirror repos below only come into play when nothing is cached either.

Every apt suite exists twice, once per upstream mirror. Nexus has no group repository type for `apt` (only maven, raw, docker, yum, npm, pypi, rubygems, go and friends), so the failover lives in the frontend: a request that the primary repo answers with `502`/`503`/`504` is re-run against the `-mirror` repo, which proxies a different host. `404` deliberately does not retry, because a missing file is missing on both mirrors and apt probes for missing files often. The frontend waits at most 8 s for a primary before it re-runs the request against the mirror; the `-mirror` locations keep the global 300 s.

Bootstrap is idempotent and runs from [bootstrap.sh](../../../roles/svc-cache-package/files/shell/bootstrap.sh) once the stack is healthy. It loops over `INFINITO_CACHE_UPSTREAMS` and holds no repository of its own.

### Package Cache Frontend 🔐

[`package-cache-frontend`](../../../compose/package-cache-frontend/README.md) runs `nginx:alpine` and reverse-proxies upstream package-manager hostnames onto the matching Nexus repo path. Combined with `extra_hosts` DNS-hijack on consumers, package managers can hit their real upstream URL and still flow through the cache.

Two listener layers:

- HTTPS (port 443): per-hostname server certs signed by a dedicated CA. Used by the `infinito` runner (Ansible-driven `pip install`, `gem install`, `composer install`, `curl https://…`). The runner trusts the CA via [ca.sh](../../../roles/svc-cache-package/files/shell/ca.sh).
- HTTP (port 80): plain mirrors for `deb.debian.org`, `archive.ubuntu.com`, `security.ubuntu.com`, `dl-cdn.alpinelinux.org`. Used by inner-`dockerd` Dockerfile builds via `build.extra_hosts` DNS-hijack. No CA-trust required in the build container.

Cert generation runs in a throw-away alpine container driven by [certs.sh](../../../roles/svc-cache-package/files/shell/certs.sh) before the frontend starts. It issues a leaf for each name in `INFINITO_CACHE_TLS_HOSTS` and holds no hostname of its own.

## Activation 🎚️

The `cache` decision is exposed via `Profile.cache_stack_enabled()` in [profile.py](../../../cli/administration/deploy/development/profile.py). When active:

- [compose/cache.override.yml](../../../compose/cache.override.yml) is layered on top of the base [compose.yml](../../../compose.yml) by [compose.py](../../../cli/administration/deploy/development/compose.py) and [down.py](../../../cli/administration/deploy/development/down.py) via [common.py](../../../cli/administration/deploy/development/common.py)`compose_file_args`.
- The cache services are added.
- The runner's `infinito` service receives:
  - bind-mounts for the registry-cache CA, the package-cache client snippets (`pip.conf`, `npmrc`, `apt/${INFINITO_DISTRO}.list`), and the frontend CA file
  - `extra_hosts` entries DNS-hijacking the HTTPS upstream hostnames to the frontend's static IP
  - `INFINITO_CACHE_PACKAGE_FRONTEND_IP` env var for the inner compose wrapper
- Cert generation, Nexus repo bootstrap, and runner trust-store install run from [compose.py](../../../cli/administration/deploy/development/compose.py).

When inactive, the override is omitted: cache services do not exist, the runner has no cache mounts or DNS-hijack, package managers go direct to upstream.

CI signals (`GITHUB_ACTIONS=true`, `INFINITO_RUNNING_ON_GITHUB=true`, `CI=true`) deactivate. Fresh runner disks per CI job give no cross-run amortization.

## Coverage Matrix 📋

| Traffic | Mechanism | Cached |
|---|---|---|
| Image pulls (any registry, inner `dockerd`) | `registry-cache` MITM via `HTTP_PROXY` env on `dockerd` | ✓ |
| `apt-get install` (Ansible task in runner) | `apt/${INFINITO_DISTRO}.list` URL-rewrite to `package-cache:8081` | ✓ |
| `pip install` (Ansible task in runner) | `pip.conf` URL-rewrite | ✓ |
| `npm install` (Ansible task in runner) | `.npmrc` URL-rewrite | ✓ |
| `gem`, `composer`, `go`, `curl https://…` (Ansible task in runner) | DNS-hijack + frontend HTTPS + runner CA-trust | ✓ |
| `RUN apt-get install` (inner Dockerfile build, Debian/Ubuntu) | `build.extra_hosts` DNS-hijack + frontend HTTP | ✓ |
| `RUN apk add` (inner Dockerfile build, Alpine ≤3.17 HTTP) | `build.extra_hosts` DNS-hijack + frontend HTTP | ✓ |
| `RUN pip/npm/gem/composer/go install` (inner Dockerfile build) | none today | ✗ |
| `RUN apk add` (Alpine ≥3.18 HTTPS) | none today | ✗ |
| App container runtime traffic (HTTPS to external API) | none today | ✗ |

The HTTPS-only inner-build gap requires per-image CA-trust bootstrap, which is out of scope for the current minimal-invasive design.

## Compose Wrapper Auto-Detection 🪄

The runner's `compose` wrapper at [roles/sys-svc-compose/files/python/compose.py](../../../roles/sys-svc-compose/files/python/compose.py) auto-detects compose files when invoked from per-app directories under `/opt/compose/<app>/`:

| File | When |
|---|---|
| `compose.yml` | always |
| `compose.override.yml` | when present (role provides it) |
| `compose.ca.override.yml` | when present (TLS self-signed CA-inject runs) |
| `compose.cache.override.yml` | generated on the fly when `INFINITO_CACHE_PACKAGE_FRONTEND_IP` is set; emits `build.extra_hosts` for every service that has a `build:` key |

[pull.py](../../../roles/sys-svc-compose/files/python/pull.py) delegates to the same wrapper so `pull` and `build --pull` operations see the identical `-f` set.

## Environment Variables 🌳

The host-side env-vars (`INFINITO_CACHE_REGISTRY_*`, `INFINITO_CACHE_PACKAGE_*`) are declared in [default.env](../../../default.env) and the dynamic ones (cache sizes from `df`/`/proc/meminfo`, sha256 admin password) are computed by [utils/env/builder.py](../../../utils/env/builder.py). `make dotenv` writes them into `.env`, which Compose auto-loads and which `BASH_ENV` makes available to every Makefile recipe through [scripts/meta/env/load.sh](../../../scripts/meta/env/load.sh). See [variables.md](variables.md).

Per-variable defaults and purposes are in [compose.yml.md](../artefact/files/compose.yml.md) under the cache section.

`INFINITO_CACHE_PACKAGE_MAX_AGE_MIN` (default `8640` = 6 days) controls how long every Nexus proxy repo holds an upstream response before revalidating. The bootstrap helper applies it as `contentMaxAge`, `metadataMaxAge`, and `negativeCache.timeToLive`. The default is intentionally one day below the 7-day `Valid-Until` window Debian and Ubuntu generate in their apt `Release` files, so Nexus always refreshes the manifest before `apt-get update` would see it expired. Raise it for slow-moving upstreams when staleness is preferable to upstream load; lower it further for fast-moving feeds (`apt-debian-security`, branch-pinned tarballs) when staleness becomes visible.

## Operations 🛠️

| Action | Command |
|---|---|
| Start the stack with caches | `make compose-up` |
| Stop the stack | `make compose-down` |
| Install this checkout's `cache:` declarations into the running stack | `make cache-apply` |
| Wipe local cache state | `make clean-cache` |
| Manually re-bootstrap Nexus repos | `bash roles/svc-cache-package/files/shell/bootstrap.sh` (after `make dotenv` or sourcing `scripts/meta/env/load.sh`) |
| Manually regenerate frontend certs | `bash roles/svc-cache-package/files/shell/certs.sh` |
| Regenerate every derived cache file | `make dotenv` |
| Reload nginx in the frontend | `docker exec infinito-package-cache-frontend nginx -s reload` |
| Inspect cache hits | `docker logs -f infinito-package-cache` and `docker logs -f infinito-package-cache-frontend` |

Cache state persists under `/var/cache/infinito/core/cache/`. Paths are configurable via the env scripts above.

## Adding a New Upstream ➕

When a new package manager or upstream needs caching:

Declare it under `cache:` in a `meta/networks.yml`, then run `make dotenv` followed by `make cache-apply`. That file is the single point of truth; the Nexus repo, the leaf cert, the nginx server block, the `extra_hosts` entries, `pip.conf`, `.npmrc` and the apt sources are all derived from it. `make dotenv` renders them, `make cache-apply` installs them into the running stack: it creates the Nexus proxy repositories, issues the frontend's leaf certificates, copies the upstream map onto the path the frontend mounts and reloads it. Recreate the checkout's runner with `make compose-up` afterwards so the new DNS hijacks reach it.

Every checkout renders and applies its own map, so a branch that declares a new host serves it without waiting for a merge. The frontend mounts one map and `make cache-apply` replaces it, so whichever checkout applied last is the one it serves. Two checkouts sharing a stack therefore overwrite each other: run `make cache-apply` from the one whose declarations you need.

A TLS upstream only reaches an inner image build when that build trusts the frontend's CA: the compose wrapper hands a build the plain-HTTP hosts by default and the full host list only when its Dockerfile runs `package-frontend-ca.sh` (see [svc-ai-ltengine](../../../roles/svc-ai-ltengine/files/Dockerfile) for the three lines and the two staging tasks that go with them).

Put the declaration in the role that needs the upstream. An upstream no single role owns goes in [svc-cache-package](../../../roles/svc-cache-package/meta/networks.yml).

```yaml
cache:
  repos:
    raw-example:
      flavor: raw
      upstream: https://example.org/
  hosts:
    example.org:
      repo: raw-example
```

A repository is proxied by Nexus. A host is additionally answered for by the frontend, so a client keeps addressing its real upstream URL. `listen: [80]` serves it over plain HTTP and issues no certificate; `paths:` maps several repositories under one host; `mirror:` on a repository names the sibling the frontend retries against on `502`, `503` or `504`; `passthrough: true` suits an upstream that hands out URLs already carrying the repository prefix.

A deployed host may correct or extend any of this from its inventory under `applications.svc-cache-package.repos` and `.upstreams`; the dev stack has no inventory and uses the declarations unchanged.

## Background 📚

- Compose-file env-var contract: [compose.yml.md](../artefact/files/compose.yml.md)
- Profile gating mechanics: [profile.py](../../../cli/administration/deploy/development/profile.py)