feat(trogon-source-discord): add Discord interaction webhook receiver

Adds Gateway WebSocket (Serenity) and HTTP Interactions Endpoint as a
single inbound dumb pipe for all Discord events into NATS JetStream.

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

devops/docker/compose/.env.example

@@ -19,6 +19,17 @@
 # LINEAR_WEBHOOK_TIMESTAMP_TOLERANCE_SECS=60
 # LINEAR_NATS_ACK_TIMEOUT_MS=10000
 
+# --- Discord Source ---
+# DISCORD_BOT_TOKEN=
+# DISCORD_GATEWAY_INTENTS=guilds,guild_members,guild_messages,guild_message_reactions,direct_messages,message_content,guild_voice_states
+# DISCORD_PUBLIC_KEY=
+# DISCORD_WEBHOOK_PORT=8080
+# DISCORD_SUBJECT_PREFIX=discord
+# DISCORD_STREAM_NAME=DISCORD
+# DISCORD_STREAM_MAX_AGE_SECS=604800
+# DISCORD_NATS_ACK_TIMEOUT_SECS=10
+# DISCORD_MAX_BODY_SIZE=4194304
+
 # --- Slack Source ---
 # SLACK_SIGNING_SECRET=
 # SLACK_WEBHOOK_PORT=3000

devops/docker/compose/compose.yml

@@ -67,6 +67,33 @@ services:
       start_period: 10s
       retries: 3
 
+  trogon-source-discord:
+    build:
+      context: ../../../rsworkspace
+      dockerfile: ../devops/docker/compose/services/trogon-source-discord/Dockerfile
+    environment:
+      NATS_URL: "nats:4222"
+      DISCORD_BOT_TOKEN: "${DISCORD_BOT_TOKEN:-}"
+      DISCORD_GATEWAY_INTENTS: "${DISCORD_GATEWAY_INTENTS:-}"
+      DISCORD_PUBLIC_KEY: "${DISCORD_PUBLIC_KEY:-}"
+      DISCORD_WEBHOOK_PORT: "${DISCORD_WEBHOOK_PORT:-8080}"
+      DISCORD_SUBJECT_PREFIX: "${DISCORD_SUBJECT_PREFIX:-discord}"
+      DISCORD_STREAM_NAME: "${DISCORD_STREAM_NAME:-DISCORD}"
+      DISCORD_STREAM_MAX_AGE_SECS: "${DISCORD_STREAM_MAX_AGE_SECS:-604800}"
+      DISCORD_NATS_ACK_TIMEOUT_SECS: "${DISCORD_NATS_ACK_TIMEOUT_SECS:-10}"
+      DISCORD_MAX_BODY_SIZE: "${DISCORD_MAX_BODY_SIZE:-4194304}"
+      RUST_LOG: "${RUST_LOG:-info}"
+    depends_on:
+      nats:
+        condition: service_healthy
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "curl", "-sf", "http://localhost:${DISCORD_WEBHOOK_PORT:-8080}/health"]
+      interval: 10s
+      timeout: 3s
+      start_period: 10s
+      retries: 3
+
   trogon-source-slack:
     build:
       context: ../../../rsworkspace
@@ -97,6 +124,7 @@ services:
     image: ngrok/ngrok:alpine
     environment:
       NGROK_AUTHTOKEN: "${NGROK_AUTHTOKEN:-}"
+      DISCORD_ADDR: "trogon-source-discord:${DISCORD_WEBHOOK_PORT:-8080}"
       GITHUB_ADDR: "trogon-source-github:${GITHUB_WEBHOOK_PORT:-8080}"
       LINEAR_ADDR: "trogon-source-linear:${LINEAR_WEBHOOK_PORT:-8080}"
       SLACK_ADDR: "trogon-source-slack:${SLACK_WEBHOOK_PORT:-3000}"
@@ -107,6 +135,9 @@ services:
         cat > /tmp/ngrok.yml <<EOF
         version: 3
         tunnels:
+          discord:
+            addr: $${DISCORD_ADDR}
+            proto: http
           github:
             addr: $${GITHUB_ADDR}
             proto: http
@@ -119,6 +150,8 @@ services:
         EOF
         exec ngrok start --all --config /tmp/ngrok.yml
     depends_on:
+      trogon-source-discord:
+        condition: service_healthy
       trogon-source-github:
         condition: service_healthy
       trogon-source-linear:

devops/docker/compose/services/trogon-source-discord/Dockerfile

@@ -0,0 +1,45 @@
+# ── Stage 1: chef — generate dependency recipe ──────────────────────────────
+FROM rust:1.93-slim AS chef
+
+RUN cargo install cargo-chef --locked
+
+WORKDIR /build
+
+# ── Stage 2: planner — capture dependency graph ─────────────────────────────
+FROM chef AS planner
+
+COPY Cargo.toml Cargo.lock ./
+COPY crates/ crates/
+
+RUN cargo chef prepare --recipe-path recipe.json
+
+# ── Stage 3: builder — cached dependency build + final compile ──────────────
+FROM chef AS builder
+
+COPY --from=planner /build/recipe.json recipe.json
+RUN cargo chef cook --release --recipe-path recipe.json -p trogon-source-discord
+
+COPY Cargo.toml Cargo.lock ./
+COPY crates/ crates/
+
+RUN cargo build --release -p trogon-source-discord && \
+    strip target/release/trogon-source-discord
+
+# ── Stage 4: runtime ────────────────────────────────────────────────────────
+FROM debian:bookworm-20250317-slim AS runtime
+
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    ca-certificates curl \
+    && rm -rf /var/lib/apt/lists/*
+
+RUN useradd --no-create-home --shell /usr/sbin/nologin trogon
+
+COPY --from=builder /build/target/release/trogon-source-discord /usr/local/bin/trogon-source-discord
+
+USER trogon
+
+EXPOSE 8080
+
+STOPSIGNAL SIGTERM
+
+ENTRYPOINT ["/usr/local/bin/trogon-source-discord"]

devops/docker/compose/services/trogon-source-discord/README.md

@@ -0,0 +1,90 @@
+# Receiving Discord Events Locally
+
+`trogon-source-discord` is the single inbound pipe for ALL Discord events into
+NATS JetStream. It supports two input paths that can run independently or
+together:
+
+- **Gateway** — WebSocket connection via the Discord Bot API (messages, reactions,
+  members, voice, etc.)
+- **HTTP Interactions Endpoint** — receives slash commands, buttons, modals, and
+  autocomplete via Discord's Interactions Endpoint URL
+
+## Prerequisites
+
+- Docker Compose
+- A [Discord Application](https://discord.com/developers/applications)
+- An [ngrok](https://ngrok.com) account (free tier works, only needed for HTTP
+  Interactions)
+
+## Gateway mode (bot token)
+
+### 1. Get your bot token
+
+1. Go to **Discord Developer Portal → Applications → your app → Bot**
+2. Copy the **Token**
+
+### 2. Start the stack
+
+```bash
+DISCORD_BOT_TOKEN=<your-bot-token> docker compose up
+```
+
+This connects to the Discord Gateway and publishes every event to NATS on
+`discord.{event_name}` subjects (e.g. `discord.message_create`,
+`discord.guild_member_add`).
+
+## HTTP Interactions mode (public key)
+
+### 1. Get your public key
+
+1. Go to **Discord Developer Portal → Applications → your app → General Information**
+2. Copy the **Public Key** (hex string)
+
+### 2. Start the stack
+
+```bash
+DISCORD_PUBLIC_KEY=<your-hex-public-key> docker compose --profile dev up
+```
+
+This starts NATS, the webhook receiver, and ngrok. Find the public tunnel URL
+in the ngrok container logs:
+
+```bash
+docker compose logs ngrok
+```
+
+### 3. Configure your Discord Application
+
+1. Go to **Discord Developer Portal → Applications → your app → General Information**
+2. Set **Interactions Endpoint URL** to `https://<ngrok-url>/webhook`
+3. Discord will send a PING to verify the endpoint — the receiver handles this
+   automatically
+
+## Both modes together
+
+```bash
+DISCORD_BOT_TOKEN=<token> DISCORD_PUBLIC_KEY=<key> docker compose --profile dev up
+```
+
+## Verify
+
+Subscribe to NATS to see events flowing:
+
+```bash
+nats sub -s nats://nats.trogonai.orb.local:4222 "discord.>"
+```
+
+Without `--profile dev`, ngrok is excluded and only the core services start.
+
+## Environment variables
+
+| Variable | Required | Default | Description |
+|---|---|---|---|
+| `DISCORD_BOT_TOKEN` | one of token/key | — | Bot token for Gateway WebSocket |
+| `DISCORD_PUBLIC_KEY` | one of token/key | — | Ed25519 public key (hex) for Interactions |
+| `DISCORD_GATEWAY_INTENTS` | no | see code | Comma-separated gateway intents |
+| `NGROK_AUTHTOKEN` | yes (dev profile) | — | ngrok auth token |
+| `DISCORD_WEBHOOK_PORT` | no | `8080` | HTTP port for the webhook receiver |
+| `DISCORD_SUBJECT_PREFIX` | no | `discord` | NATS subject prefix |
+| `DISCORD_STREAM_NAME` | no | `DISCORD` | JetStream stream name |
+| `RUST_LOG` | no | `info` | Log level |