ZDDC
b5aab81d31
New endpoint GET /<path>/foo.md?convert=docx|html|pdf renders a markdown source on demand. Surfaced as the Download buttons in browse's markdown editor (separate commit). Execution model — two upstream container images, lazy-pulled: • docker.io/pandoc/latex:latest — MD→DOCX, MD→HTML (entrypoint pandoc) • docker.io/zenika/alpine-chrome — HTML→PDF (entrypoint chromium-browser) No custom image build. The runner passes --pull=missing on every podman/ docker invocation so the operator only needs the runtime installed — first request pulls the image, subsequent requests use the local cache. Overrides: --convert-pandoc-image / --convert-chromium-image (and the matching ZDDC_CONVERT_* env vars). Engine: --convert-engine (podman preferred, docker fallback). Resource caps: --convert-mem-mib (512), --convert-cpus (2), --convert-pids (100), --convert-timeout (30s). PDF flow is two-stage: pandoc renders the markdown through the embedded viewer-template.html to standalone HTML, then chromium prints that HTML via --print-to-pdf. Preserves the print-media CSS already authored in viewer-template.html rather than going through pandoc's LaTeX template. Each conversion runs in a throw-away container with --rm --network=none --read-only --tmpfs=/tmp --cap-drop=ALL --security-opt=no-new-privileges --env=HOME=/tmp plus a bind-mounted scratch dir for I/O. Pandoc reads markdown from stdin / writes to stdout; the viewer template lives at /tpl (ro). Chromium reads HTML from a read-write bind mount at /pdf and writes the PDF to the same mount; the host reads it back. No shell wrappers, no shell quoting — argv flows straight into each image's entrypoint. On-disk cache at <dir>/.converted/<base>.<ext> with mtime synced to the source. Fast path is a stat-and-serve with no exec; slow path singleflights concurrent requests for the same target. PUT/DELETE/MOVE on the source .md purges the .converted/ sidecars. Per-project template variables (client/project/contractor/project_number) come from a new .zddc `convert:` cascade block, walked leaf→root with per-key latest-wins. Filename-derived variables (title, tracking_number, revision, status, is_draft) come from a new zddc.ParseFilename helper. If neither podman nor docker is on PATH, the endpoint serves 503 with a clear Retry-After. The rest of the server keeps working. This is the first os/exec site in the codebase. The hardening in internal/convert/runner.go — context.CancelFunc → process kill, cmd.WaitDelay, platform-specific SysProcAttr (Setpgid + Pdeathsig on Linux), minimal env, stdout cap via limitWriter, stderr ring buffer — sets the pattern for any future shell-outs. Public surface: convert.ToDocx(ctx, source, meta) / .ToHTML / .ToPDF convert.Probe(ctx, engineOverride) → install Runner if engine present convert.SetImages(pandoc, chromium) convert.ConfigureLimits(memMiB, cpus, pids, timeout) convert.Available() Container handler at internal/handler/converthandler.go; dispatcher branch in cmd/zddc-server/main.go inserts the convert lookup after the existing ACL gate, reusing the source file's read policy verbatim.
19 lines
703 B
Go
19 lines
703 B
Go
package convert
|
|
|
|
import _ "embed"
|
|
|
|
// Pandoc HTML template and its companion stylesheet, copied verbatim from
|
|
// /pandoc/viewer-template.html and /pandoc/custom.css. The runner writes
|
|
// these to a host scratch dir on each conversion and bind-mounts them
|
|
// read-only into the container so pandoc can `--template` against them.
|
|
//
|
|
// Refresh: when /pandoc/viewer-template.html changes, copy the new bytes
|
|
// here. There's no symlink because go:embed paths must resolve under the
|
|
// containing module — and we want the binary to ship the bytes verbatim,
|
|
// not depend on the source tree at runtime.
|
|
|
|
//go:embed viewer-template.html
|
|
var viewerTemplate []byte
|
|
|
|
//go:embed custom.css
|
|
var customCSS []byte
|