Pole Sidecar data plane

Run Pole Sidecar for local HTTP/gRPC routing while consuming control-plane active views.

Pole Sidecar fits multi-language services or teams that want governance in a local proxy. Forwarding is local; discovery and policy facts still come from Lattice Hub.

sidecar data plane

When to choose Sidecar

Choose Sidecar	Choose SDK
Multi-language / hard to change code	Rust apps can embed directly
Need a unified local forward/intercept point	Prefer proxyless, one fewer hop
Pair with Controller injection	Mature SDK governance path already exists

Quick start

cargo build
RUST_LOG=info cargo run
SIDECAR_CONFIG=./sidecar.toml RUST_LOG=debug cargo run

Requires Rust 1.74+. Match grpc_prefix before prefix. Sample LB is round-robin. Full sample TOML is in the Chinese practice page / pole-sidecar/sidecar.toml (inbound 8080, /api/ → backend_http, gRPC Greeter → backend_grpc).

Community demo

Entry	What it does
Local sample	`pole-sidecar/sidecar.toml` + `RUST_LOG=info cargo run`
Design docs	`pole-sidecar/docs/design/`
K8s inject	`pole-controller` `sidecarInject.mode=dns
SDK contrast	`pole-client-rust/examples/{discover,config}.rs`

cd pole-sidecar
cargo build
# start a local upstream on 127.0.0.1:9000, then:
RUST_LOG=info cargo run

How to verify

curl -sS -D - http://127.0.0.1:8080/api/hello
# expect forward to cluster backend_http endpoints per [[routes]] prefix=/api/

Also verify gRPC via grpc_prefix + content-type: application/grpc, and on Kubernetes check injected sidecar containers, readiness, and outbound targets. When pairing with governance, publish active route/rate-limit releases first, then observe proxy behavior—separate “rule not published” from “proxy not consuming”.

Expected effects

Scenario	Effect
HTTP `prefix=/api/` match	Forward to `backend_http` (round-robin)
gRPC `grpc_prefix` match	Forward to `backend_grpc`
No route match	Local reject / no forward (per Sidecar version)
dns inject	Discovery via DNS interception
mesh inject	Traffic hijack; deeper intercept hooks
Local TOML only	Local routing may change; TOML is not cluster governance truth

Collaboration rules

Control plane owns active service/config/governance views.
Sidecar consumes those views; local TOML is not the long-term source of truth.
Interceptor hooks should evaluate active configuration.
Pair with Controller dns / mesh injection on Kubernetes.

Checklist

Cluster endpoints in Sidecar config are correct
Route prefixes do not collide; gRPC paths are complete
Control-plane active rules are published
Upstream reachability and timeouts are acceptable
Debug logging can be raised for triage
Sidecar is not described as a control-plane replacement