Pim van Pelt
284b4cc9a4
Introduces maglev-frontend, a responsive, real-time web dashboard for one
or more running maglevd instances. Source lives at cmd/frontend/; the
built binary is maglev-frontend. It is a single Go process with the
SolidJS SPA embedded via //go:embed — no runtime file dependencies.
Architecture
- One persistent gRPC connection per configured maglevd (-server A,B,C).
Each connection runs three background loops: a WatchEvents stream
subscribed at log_level=debug for live events, a 30s refresh loop as
a safety net for drift, and a 5s health loop that surfaces connection
drops quickly.
- In-process pub/sub broker with a 30s / 2000-event replay ring using
<epoch>-<seq> monotonic IDs. Short browser reconnects (nginx idle,
wifi flap, laptop wake) silently replay buffered events via the
EventSource Last-Event-ID header; longer outages or frontend restarts
fall through to a "resync" event that triggers a full state refetch.
- HTTP surface: /view/ (SPA), /view/api/state, /view/api/state/{name},
/view/api/maglevds, /view/api/version, /view/api/events (SSE),
/healthz, and an /admin/* placeholder returning 501 for a future
basic-auth mutation surface.
- SSE handler follows the full operational checklist: retry hint, 15s
: ping heartbeat, Flush after every write, r.Context().Done() teardown,
X-Accel-Buffering: no, and no gzip.
SolidJS SPA (cmd/frontend/web/, Vite + TypeScript)
- solid-js/store for a reactive per-maglevd state tree; reducers apply
backend transitions, maglevd-status flips, and resync refetches.
- Scope selector tabs for multi-maglevd support, per-maglevd frontend
cards with pool tables showing state, configured weight, effective
weight, and last-transition age.
- ProbeHeartbeat component turns a middle-dot into ❤️ on probe-start and
back on probe-done, driven by real log events; fixed-size wrapper so
the emoji swap doesn't jiggle the row.
- Flash wrapper animates any primitive on change (1s yellow fade via
Web Animations API, skipped on first mount). Wired into the state
badge, configured weight, and effective weight columns.
- DebugPanel: chronological rolling event tail with tail-style auto-
scroll, pause/resume, and scope/firehose filter. Syntactic highlight
for vpp-lb-sync-* events with fixed-order attribute formatting.
- Live effective_weight updates: vpp-lb-sync-as-added/removed/weight-
updated log events are routed through a reducer that walks the
snapshot's pool rows and sets effective_weight on every match
without waiting for the 30s refresh.
- Header shows build version + commit with build date in a tooltip,
fetched once from /view/api/version on mount.
- Prettier wired in as the web-side fixstyle; make fixstyle now tidies
both Go and web in one shot via a new fixstyle-web target.
Per-mutation VPP LB sync logging
- Promotes the addVIP/delVIP/addAS/delAS/setASWeight helpers from
slog.Debug to slog.Info and renames them from vpp-lbsync-* to
vpp-lb-sync-{vip-added,vip-removed,as-added,as-removed,as-weight-
updated}. Matching rename for vpp-lb-sync-start / -done / -error /
-vip-recreate. The Prometheus metric name (maglev_vpp_lbsync_total)
is left alone to preserve dashboards.
- setASWeight now takes the prior weight so the event can emit
from=X to=Y and the UI can show the delta.
- The vip field in every event is the bare address (no /32 or /128
mask), matching the CLI output style.
- Any listener on the gRPC WatchEvents stream — CLI watch events or
maglev-frontend — now sees every VIP/AS dataplane change in real
time without needing to raise the log level.
Build and tooling
- Makefile: maglev-frontend added to BINARIES; build / build-amd64 /
build-arm64 emit the binary alongside maglevd and maglevc. A new
maglev-frontend-web target rebuilds the SolidJS bundle via npm.
- web/dist/ is tracked so a bare `go build` keeps working for Go-only
contributors and CI.
- .gitignore skips cmd/frontend/web/node_modules/.
Stability fixes
- maglevd's WatchEvents synthetic replay events (from==to, at_unix_ns=0)
were corrupting the frontend's LastTransition cache with at=0,
rendering as "20555d ago" in the browser. Client now skips synthetic
events: the cache comes from refreshAll and doesn't need them.
- Frontends, Backends, and HealthChecks are now served in the order
returned by the corresponding List* RPC instead of Go map iteration
order, so reloads and refreshes keep the SPA stable.
maglevd
Health checker and gRPC control plane for VPP Maglev load balancing.
Build and Install
make # builds build/<arch>/maglevd and build/<arch>/maglevc
make test # runs all tests
make pkg-deb # Creates a debian package for arm64 and amd64
Requires Go 1.25+ and (for make proto) protoc with protoc-gen-go and
protoc-gen-go-grpc.
Produces vpp-maglev_<version>_amd64.deb and vpp-maglev_<version>_arm64.deb
in the build/ directory by cross-compiling with GOOS=linux GOARCH=<arch>.
Requires dpkg-deb (available on any Debian/Ubuntu host).
Running
After installing, the unit is enabled but not started automatically:
# edit /etc/vpp-maglev/maglev.yaml, then:
systemctl enable --now vpp-maglevd
Or run the server and client by hand:
maglevd --config /etc/vpp-maglev/maglev.yaml --grpc-addr :9090
maglevd --version # print version and exit
maglevc --server localhost:9090 # interactive shell
maglevc show frontends # one-shot
maglevc -color=false show backends # one-shot, no ANSI color
maglevc set backend nginx0-ams pause
Send SIGHUP to maglevd to reload config without restarting.
maglevd requires CAP_NET_RAW for ICMP health checks.
Check out a minimal configuration file in [debian/maglev.yaml].
See docs/user-guide.md for flags, signals, and maglevc usage.
See docs/config-guide.md for the full configuration reference.
See docs/healthchecks.md for health state machine details.
Docker
docker build -t maglevd .
docker run --cap-add NET_RAW -v /etc/vpp-maglev:/etc/vpp-maglev maglevd