chore: improve s2-lite local-dev onboarding

Adds a commented s2-lite block to .env.example so contributors know how to
enable v2 streams (Sessions / chat.agent) against the existing `s2` docker
service, and drops the broken healthcheck on the distroless s2-lite image
that always reports unhealthy.

Author: ericallam

.env.example

@@ -29,6 +29,17 @@ REDIS_TLS_DISABLED="true"
 DEV_OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:3030/otel"
 DEV_OTEL_BATCH_PROCESSING_ENABLED="0"
 
+# Realtime streams v2 (Sessions, chat.agent, large stream backfills) backed
+# by S2 (https://s2.dev). The `s2` service in docker/docker-compose.yml runs
+# the open-source s2-lite binary and pre-creates a basin named `trigger-local`
+# (see docker/config/s2-spec.json). Comment these out to fall back to v1
+# (Redis-only) streams; Sessions and chat.agent then become unavailable.
+REALTIME_STREAMS_S2_BASIN=trigger-local
+REALTIME_STREAMS_S2_ACCESS_TOKEN=ignored
+REALTIME_STREAMS_S2_ENDPOINT=http://localhost:4566/v1
+REALTIME_STREAMS_S2_SKIP_ACCESS_TOKENS=true
+REALTIME_STREAMS_DEFAULT_VERSION=v2
+
 # When the domain is set to `localhost` the CLI deploy command will only --load the image by default and not --push it
 DEPLOY_REGISTRY_HOST=localhost:5000
 

docker/docker-compose.yml

@@ -184,6 +184,10 @@ services:
     networks:
       - app_network
 
+  # s2-lite: open-source S2 (https://s2.dev) for local realtime streams v2.
+  # The image is distroless (no shell), so a `wget` / `curl` healthcheck
+  # always reports unhealthy even when the API is responding. No other
+  # service depends on this one, so the healthcheck is omitted.
   s2:
     image: ghcr.io/s2-streamstore/s2
     command: ["lite", "--init-file", "/s2-spec.json"]
@@ -193,12 +197,6 @@ services:
       - "4566:80"
     networks:
       - app_network
-    healthcheck:
-      test: ["CMD-SHELL", "wget -qO- http://localhost:80/v1/basins?limit=1 || exit 1"]
-      interval: 2s
-      timeout: 3s
-      retries: 5
-      start_period: 3s
 
   toxiproxy:
     container_name: toxiproxy