feat: add axiom and otlp adapters (#35)

Author: HugoRCD

apps/docs/app/assets/icons/axiom.svg

@@ -25,20 +25,20 @@ log.set({ cart: { items, total } })
 })`,
   },
   {
-    title: 'Agent-Ready',
-    description: 'Structured JSON output that AI agents can parse and understand.',
-    code: `{
-  "level": "error",
-  "why": "Card declined",
-  "fix": "Try another card"
-}`,
+    title: 'Log Draining',
+    description: 'Send logs to external services in fire-and-forget mode. Never blocks your response.',
+    code: `nitroApp.hooks.hook('evlog:drain',
+  async (ctx) => {
+    await sendToAxiom(ctx.event)
+  }
+)`,
   },
   {
-    title: 'Nuxt & Nitro',
-    description: 'First-class integration. Auto-create loggers, auto-emit at request end.',
-    code: `export default defineNuxtConfig({
-  modules: ['evlog/nuxt'],
-})`,
+    title: 'Built-in Adapters',
+    description: 'Zero-config adapters for Axiom, OTLP (Grafana, Datadog, Honeycomb), or build your own.',
+    code: `import { createAxiomDrain } from 'evlog/axiom'
+import { createOTLPDrain } from 'evlog/otlp'
+// Reads config from env vars`,
   },
   {
     title: 'Smart Sampling',
@@ -47,6 +47,21 @@ log.set({ cart: { items, total } })
   rates: { info: 10, warn: 50 },
   keep: [{ status: 400 }]
 }`,
+  },
+  {
+    title: 'Nuxt & Nitro',
+    description: 'First-class integration. Auto-create loggers, auto-emit at request end.',
+    code: `export default defineNuxtConfig({
+  modules: ['evlog/nuxt'],
+})`,
+  },
+  {
+    title: 'Client Transport',
+    description: 'Send browser logs to your server. Automatic enrichment with server context.',
+    code: `// Browser
+log.info({ action: 'click' })
+// → Sent to /api/_evlog/ingest
+// → Enriched & drained server-side`,
   },
   {
     title: 'Pretty & JSON',
@@ -55,6 +70,15 @@ log.set({ cart: { items, total } })
   user: { id: 1, plan: "pro" }
   cart: { items: 3 }`,
   },
+  {
+    title: 'Agent-Ready',
+    description: 'Structured JSON output that AI agents can parse and understand.',
+    code: `{
+  "level": "error",
+  "why": "Card declined",
+  "fix": "Try another card"
+}`,
+  },
 ]
 </script>
 

apps/docs/app/assets/icons/plug.svg

@@ -0,0 +1,2 @@
+title: Adapters
+icon: i-custom-plug

apps/docs/app/components/LandingFeatures.vue

@@ -0,0 +1,103 @@
+---
+title: Overview
+description: Send your logs to external services with evlog adapters.
+---
+
+Adapters let you send logs to external observability platforms. evlog provides built-in adapters for popular services, and you can create custom adapters for any destination.
+
+## How Adapters Work
+
+Adapters hook into the `evlog:drain` event, which fires after each request completes. The drain runs in **fire-and-forget** mode, meaning it never blocks the HTTP response.
+
+```typescript [server/plugins/evlog-drain.ts]
+import { createAxiomDrain } from 'evlog/axiom'
+
+export default defineNitroPlugin((nitroApp) => {
+  nitroApp.hooks.hook('evlog:drain', createAxiomDrain())
+})
+```
+
+## Available Adapters
+
+::card-group
+  :::card
+  ---
+  icon: i-custom-axiom
+  title: Axiom
+  to: /adapters/axiom
+  ---
+  Send logs to Axiom for powerful querying and dashboards.
+  :::
+
+  :::card
+  ---
+  icon: i-simple-icons-opentelemetry
+  title: OTLP
+  to: /adapters/otlp
+  ---
+  OpenTelemetry Protocol for Grafana, Datadog, Honeycomb, and more.
+  :::
+
+  :::card
+  ---
+  icon: i-lucide-code
+  title: Custom
+  to: /adapters/custom
+  ---
+  Build your own adapter for any destination.
+  :::
+::
+
+## Multiple Destinations
+
+Send logs to multiple services simultaneously:
+
+```typescript [server/plugins/evlog-drain.ts]
+import { createAxiomDrain } from 'evlog/axiom'
+import { createOTLPDrain } from 'evlog/otlp'
+
+export default defineNitroPlugin((nitroApp) => {
+  const axiom = createAxiomDrain()
+  const otlp = createOTLPDrain()
+
+  nitroApp.hooks.hook('evlog:drain', async (ctx) => {
+    await Promise.allSettled([axiom(ctx), otlp(ctx)])
+  })
+})
+```
+
+## Drain Context
+
+Every adapter receives a `DrainContext` with:
+
+| Field | Type | Description |
+|-------|------|-------------|
+| `event` | `WideEvent` | The complete log event with all accumulated context |
+| `request` | `object` | Request metadata (`method`, `path`, `requestId`) |
+| `headers` | `object` | Safe HTTP headers (sensitive headers are filtered) |
+
+::callout{icon="i-lucide-shield-check" color="success"}
+**Security:** Sensitive headers (`authorization`, `cookie`, `x-api-key`, etc.) are automatically filtered and never passed to adapters.
+::
+
+## Zero-Config Setup
+
+All adapters support automatic configuration via environment variables. No code changes needed when deploying to different environments:
+
+```bash [.env]
+# Axiom
+NUXT_AXIOM_TOKEN=xaat-xxx
+NUXT_AXIOM_DATASET=my-logs
+
+# OTLP
+NUXT_OTLP_ENDPOINT=https://otlp.example.com
+```
+
+```typescript [server/plugins/evlog-drain.ts]
+import { createAxiomDrain } from 'evlog/axiom'
+
+export default defineNitroPlugin((nitroApp) => {
+  // Automatically reads from env vars
+  nitroApp.hooks.hook('evlog:drain', createAxiomDrain())
+})
+```

apps/docs/content/3.adapters/.navigation.yml

@@ -0,0 +1,164 @@
+---
+title: Axiom
+description: Send logs to Axiom for powerful querying, dashboards, and alerting.
+---
+
+[Axiom](https://axiom.co) is a cloud-native logging platform with powerful querying capabilities. The evlog Axiom adapter sends your wide events directly to Axiom datasets.
+
+## Installation
+
+The Axiom adapter is included in the main evlog package:
+
+```typescript
+import { createAxiomDrain } from 'evlog/axiom'
+```
+
+## Quick Start
+
+### 1. Get your Axiom credentials
+
+1. Create an [Axiom account](https://app.axiom.co)
+2. Create a dataset for your logs
+3. Generate an API token with ingest permissions
+
+### 2. Set environment variables
+
+```bash [.env]
+NUXT_AXIOM_TOKEN=xaat-your-token-here
+NUXT_AXIOM_DATASET=your-dataset-name
+```
+
+### 3. Create the drain plugin
+
+```typescript [server/plugins/evlog-drain.ts]
+import { createAxiomDrain } from 'evlog/axiom'
+
+export default defineNitroPlugin((nitroApp) => {
+  nitroApp.hooks.hook('evlog:drain', createAxiomDrain())
+})
+```
+
+That's it! Your logs will now appear in Axiom.
+
+## Configuration
+
+The adapter reads configuration from multiple sources (highest priority first):
+
+1. **Overrides** passed to `createAxiomDrain()`
+2. **Runtime config** at `runtimeConfig.evlog.axiom`
+3. **Runtime config** at `runtimeConfig.axiom`
+4. **Environment variables** (`NUXT_AXIOM_*` or `AXIOM_*`)
+
+### Environment Variables
+
+| Variable | Description |
+|----------|-------------|
+| `NUXT_AXIOM_TOKEN` | API token with ingest permissions |
+| `NUXT_AXIOM_DATASET` | Dataset name to ingest logs into |
+| `NUXT_AXIOM_ORG_ID` | Organization ID (required for Personal Access Tokens) |
+
+You can also use `AXIOM_TOKEN`, `AXIOM_DATASET`, and `AXIOM_ORG_ID` as fallbacks.
+
+### Runtime Config
+
+Configure via `nuxt.config.ts` for type-safe configuration:
+
+```typescript [nuxt.config.ts]
+export default defineNuxtConfig({
+  runtimeConfig: {
+    axiom: {
+      token: '', // Set via NUXT_AXIOM_TOKEN
+      dataset: '', // Set via NUXT_AXIOM_DATASET
+    },
+  },
+})
+```
+
+### Override Options
+
+Pass options directly to override any configuration:
+
+```typescript [server/plugins/evlog-drain.ts]
+import { createAxiomDrain } from 'evlog/axiom'
+
+export default defineNitroPlugin((nitroApp) => {
+  nitroApp.hooks.hook('evlog:drain', createAxiomDrain({
+    dataset: 'production-logs',
+    timeout: 10000, // 10 seconds
+  }))
+})
+```
+
+### Full Configuration Reference
+
+| Option | Type | Default | Description |
+|--------|------|---------|-------------|
+| `token` | `string` | - | API token (required) |
+| `dataset` | `string` | - | Dataset name (required) |
+| `orgId` | `string` | - | Organization ID (for PAT tokens) |
+| `baseUrl` | `string` | `https://api.axiom.co` | Axiom API base URL |
+| `timeout` | `number` | `5000` | Request timeout in milliseconds |
+
+## Querying Logs in Axiom
+
+evlog sends structured wide events that are perfect for Axiom's APL query language:
+
+```apl
+// Find slow requests
+['your-dataset']
+| where duration > 1000
+| project timestamp, path, duration, status
+
+// Error rate by endpoint
+['your-dataset']
+| where level == "error"
+| summarize count() by path
+| order by count_ desc
+
+// Request volume over time
+['your-dataset']
+| summarize count() by bin(timestamp, 1h)
+| render timechart
+```
+
+## Troubleshooting
+
+### Missing dataset or token error
+
+```
+[evlog/axiom] Missing dataset or token. Set NUXT_AXIOM_DATASET and NUXT_AXIOM_TOKEN
+```
+
+Make sure your environment variables are set and the server was restarted after adding them.
+
+### 401 Unauthorized
+
+Your token may be invalid or expired. Generate a new token in the Axiom dashboard with **Ingest** permissions.
+
+### 403 Forbidden with PAT tokens
+
+Personal Access Tokens require an organization ID:
+
+```bash [.env]
+NUXT_AXIOM_ORG_ID=your-org-id
+```
+
+## Direct API Usage
+
+For advanced use cases, you can use the lower-level functions:
+
+```typescript
+import { sendToAxiom, sendBatchToAxiom } from 'evlog/axiom'
+
+// Send a single event
+await sendToAxiom(event, {
+  token: 'xaat-xxx',
+  dataset: 'logs',
+})
+
+// Send multiple events in one request
+await sendBatchToAxiom(events, {
+  token: 'xaat-xxx',
+  dataset: 'logs',
+})
+```