a6-plugin-http-logger

Overview

The http-logger plugin pushes request/response logs as JSON to HTTP or HTTPS endpoints. Logs are batched for efficiency and support custom formats using NGINX variables. Use it to send structured logs to any HTTP-based logging backend (Elasticsearch, Loki, custom APIs, etc.).

When to Use

• Ship access logs to an HTTP-based logging backend
• Custom log formats with selected fields only
• Conditional request/response body capture
• Batch log delivery with retry on failure

Plugin Configuration Reference

Field	Type	Required	Default	Description
uri	string	Yes	—	HTTP/HTTPS endpoint for log delivery
auth_header	string	No	—	Authorization header value
timeout	integer	No	3	Connection timeout in seconds
log_format	object	No	—	Custom log format (supports $variable syntax)
include_req_body	boolean	No	false	Include request body in logs
include_req_body_expr	array	No	—	Conditional expression for request body logging
include_resp_body	boolean	No	false	Include response body in logs
include_resp_body_expr	array	No	—	Conditional expression for response body logging
concat_method	string	No	"json"	Batch format: json (array) or new_line (newline-separated)
ssl_verify	boolean	No	false	Verify SSL certificate for HTTPS endpoints

Batch Processing Parameters

Field	Type	Default	Description
batch_max_size	integer	1000	Max entries per batch
inactive_timeout	integer	5	Seconds before flushing incomplete batch
buffer_duration	integer	60	Max age of oldest entry before forced flush
max_retry_count	integer	0	Retry attempts on failure
retry_delay	integer	1	Seconds between retries

Default Log Entry Format

When no custom log_format is set, each log entry contains:

{
  "client_ip": "127.0.0.1",
  "route_id": "1",
  "service_id": "",
  "start_time": 1703907485819,
  "latency": 101.9,
  "apisix_latency": 100.9,
  "upstream_latency": 1,
  "upstream": "127.0.0.1:8080",
  "request": {
    "method": "GET",
    "uri": "/api/users",
    "url": "http://127.0.0.1:9080/api/users",
    "size": 194,
    "headers": { "host": "...", "user-agent": "..." },
    "querystring": {}
  },
  "response": {
    "status": 200,
    "size": 123,
    "headers": { "content-type": "...", "content-length": "..." }
  },
  "server": {
    "hostname": "gateway-1",
    "version": "3.15.0"
  }
}

Step-by-Step: Ship Logs to an HTTP Endpoint

1. Create a route with http-logger

a6 route create -f - <<'EOF'
{
  "id": "logged-api",
  "uri": "/api/*",
  "plugins": {
    "http-logger": {
      "uri": "http://log-collector:8080/logs",
      "batch_max_size": 100,
      "inactive_timeout": 10
    }
  },
  "upstream": {
    "type": "roundrobin",
    "nodes": {
      "backend:8080": 1
    }
  }
}
EOF

2. Verify logs are arriving

curl http://127.0.0.1:9080/api/hello
# Check your log collector for the entry

Common Patterns

Custom log format with NGINX variables

{
  "plugins": {
    "http-logger": {
      "uri": "http://log-collector:8080/logs",
      "log_format": {
        "@timestamp": "$time_iso8601",
        "client_ip": "$remote_addr",
        "host": "$host",
        "method": "$request_method",
        "uri": "$request_uri",
        "status": "$status",
        "latency": "$request_time",
        "upstream_addr": "$upstream_addr"
      }
    }
  }
}

Authenticated endpoint

{
  "plugins": {
    "http-logger": {
      "uri": "https://log-service.example.com/api/v1/logs",
      "auth_header": "Bearer eyJhbGciOiJIUzI1NiIs...",
      "ssl_verify": true,
      "timeout": 5
    }
  }
}

Conditional request body logging

Log request bodies only when a query parameter is present:

{
  "plugins": {
    "http-logger": {
      "uri": "http://log-collector:8080/logs",
      "include_req_body": true,
      "include_req_body_expr": [
        ["arg_debug", "==", "true"]
      ]
    }
  }
}

Newline-delimited JSON (for Elasticsearch bulk API)

{
  "plugins": {
    "http-logger": {
      "uri": "http://elasticsearch:9200/_bulk",
      "concat_method": "new_line"
    }
  }
}

Aggressive batching for high-traffic routes

{
  "plugins": {
    "http-logger": {
      "uri": "http://log-collector:8080/logs",
      "batch_max_size": 5000,
      "inactive_timeout": 30,
      "buffer_duration": 120,
      "max_retry_count": 3,
      "retry_delay": 2
    }
  }
}

Config Sync Example

version: "1"
routes:
  - id: logged-api
    uri: /api/*
    plugins:
      http-logger:
        uri: http://log-collector:8080/logs
        batch_max_size: 200
        inactive_timeout: 10
        log_format:
          timestamp: "$time_iso8601"
          client_ip: "$remote_addr"
          method: "$request_method"
          uri: "$request_uri"
          status: "$status"
    upstream_id: my-upstream

Troubleshooting

Symptom	Cause	Fix
No logs arriving	Wrong uri or endpoint down	Verify endpoint is reachable from APISIX
SSL handshake failure	Certificate not trusted	Set ssl_verify: false for self-signed certs
Logs delayed	Large inactive_timeout	Lower inactive_timeout for faster delivery
Logs dropped	Buffer overflow	Increase batch_max_size; reduce delivery latency
Missing request body	include_req_body: false	Set to true (caution: memory impact)
Auth rejected	Wrong auth_header value	Include full header value (e.g. Bearer <token>)