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.
44 lines
949 B
Go
44 lines
949 B
Go
package handler
|
|
|
|
import "sync"
|
|
|
|
// singleflightGroup deduplicates concurrent calls keyed by string. If N
|
|
// goroutines call Do(key, fn) before the first one returns, fn runs once
|
|
// and all callers receive the same (val, err).
|
|
//
|
|
// Copy of internal/apps/singleflight.go (same pattern, no extra
|
|
// dependency). The convert package has its own copy too; if a third
|
|
// caller appears, lift to internal/sf/.
|
|
type singleflightGroup struct {
|
|
mu sync.Mutex
|
|
m map[string]*sfCall
|
|
}
|
|
|
|
type sfCall struct {
|
|
done chan struct{}
|
|
val any
|
|
err error
|
|
}
|
|
|
|
func (g *singleflightGroup) Do(key string, fn func() (any, error)) (any, error) {
|
|
g.mu.Lock()
|
|
if g.m == nil {
|
|
g.m = make(map[string]*sfCall)
|
|
}
|
|
if c, ok := g.m[key]; ok {
|
|
g.mu.Unlock()
|
|
<-c.done
|
|
return c.val, c.err
|
|
}
|
|
c := &sfCall{done: make(chan struct{})}
|
|
g.m[key] = c
|
|
g.mu.Unlock()
|
|
|
|
c.val, c.err = fn()
|
|
close(c.done)
|
|
|
|
g.mu.Lock()
|
|
delete(g.m, key)
|
|
g.mu.Unlock()
|
|
return c.val, c.err
|
|
}
|