Log

You can capture the current message state at any point in the API Proxy message pipeline and send it to selected connectors. This policy enables mid-pipeline snapshot logging across HTTP, WebSocket, and gRPC protocols.

This document describes the detailed usage of a specific policy. If you are using the Apinizer policy structure for the first time or want to learn the general operating principles of policies, we recommend reading the What is Policy? page first.

​

Overview

​

Purpose

• The Log Policy captures a snapshot of the current message state at any point in the message processing pipeline and sends it to designated connectors.
• Unlike standard traffic logging, it enables logging at intermediate points in the pipeline (e.g., before and after a transformation policy) to track message changes.
• Works across HTTP, WebSocket, and gRPC protocols.
• Can send to multiple connectors simultaneously.

​

How It Works

1. Policy Trigger: The policy executes when its turn comes in the message processing pipeline.
2. Snapshot Creation: The current message state is captured in a protocol-specific manner (headers, parameters, body).
3. Connector Delivery: The snapshot is sent to each defined connector individually.
4. Privacy Application: If privacy settings are enabled, sensitive data is processed before delivery (masking, deletion, hashing, encryption).

​

Features and Capabilities

​

Core Features

• Sync/Async Execution: In synchronous mode, the pipeline waits until delivery is complete; in asynchronous mode, the pipeline continues while delivery happens in the background.
• Multi-Protocol Support: Works across HTTP, WebSocket, and gRPC protocols.
• Multi-Connector Delivery: The same snapshot can be sent to multiple connectors.
• Field-Level Control: Headers, parameters, body, metadata, and metrics can each be independently enabled or disabled.
• Body Size Limiting: Body data can be logged fully or partially. In partial mode, a maximum size can be specified.
• Policy-Level Privacy: Masking, deletion, hashing, or encryption can be applied to sensitive data.
• Condition-Based Execution: Define conditions to ensure the policy only runs in specific situations.

​

Protocol Support

Protocol	Header	Parameter	Body
HTTP	✓	✓	✓
WebSocket	✓	—	✓
gRPC	—	—	✓

Header and parameter information may be limited in WebSocket and gRPC protocols due to their protocol structure.

​

Configuration Fields

​

General Settings

Field	Description
Name	Descriptive name of the policy
Description	Description explaining the purpose of the policy
Active	Active/inactive status of the policy
Execution Mode	Synchronous or Asynchronous execution mode (detailed below)
Condition	Condition determining when the policy executes (optional)

​

Connector Selection

You can select the connectors to which the policy will send logs. Connectors are selected through connection definitions and work independently of environments — the same connection definition may correspond to different connector instances in different environments.

A log policy defined as a global policy works across all environments. In each environment, the connector corresponding to the relevant connection definition is automatically matched.

​

Logged Fields

You can determine which of the following field groups are included in the log record:

Field Group	Description
Request Headers from Client	Request header information from client to API Proxy
Request Parameters from Client	Request parameters from client to API Proxy
Request Body from Client	Request body from client to API Proxy
Request Headers to Target	Request header information sent from API Proxy to Backend API
Request Parameters to Target	Request parameters sent from API Proxy to Backend API
Request Body to Target	Request body sent from API Proxy to Backend API
Response Headers from Target	Response header information from Backend API
Response Body from Target	Response body from Backend API
Response Headers to Client	Response header information sent to client
Response Body to Client	Response body sent to client
Metadata	Request metadata such as IP address, HTTP method, URI, port
Metrics	Performance metrics such as duration, size, cache status

​

Body Logging Mode

Mode	Description
Full	Body data is logged completely
Partial	Body data is logged up to the specified maximum size. Data is truncated when the size is exceeded

​

Privacy Settings

You can configure privacy settings at the policy level to process sensitive data before it is written to the log record.

Operation	Description
Mask	Partially hides sensitive data (e.g., ****1234)
Delete	Completely removes sensitive data
Hash	Converts sensitive data to a one-way hash value
Encrypt	Encrypts sensitive data

Privacy settings are applied at two levels: first the policy-level settings, then the connector-level settings. If both levels are enabled, both are applied in sequence.

​

Sync and Async Execution

Mode	Delivery	Error Behavior	Pipeline Impact
Synchronous (default)	Sequential, waits for completion	Error is thrown	Pipeline breaks
Asynchronous	Background, non-blocking	Error is logged, suppressed	Pipeline continues

In synchronous mode, a connector error breaks the pipeline and returns an error to the client. If uninterrupted operation is required in production, prefer asynchronous mode.

In asynchronous mode, when a connector error occurs, the error information is written to application logs, but the client request is not affected.

​

Use Cases

Scenario	Description	Recommended Mode
Pre/post transformation comparison	Add log policies before and after a transformation policy to track message changes	Async
Debugging	Add a temporary log point to the pipeline to inspect a specific policy’s input and output	Sync
Audit trail	Maintain a complete record of every request to sensitive APIs	Async
Multi-target logging	Send the same message to Elasticsearch and Kafka simultaneously	Async
Conditional logging	Log only requests matching a specific header value or path	Async

​

Related Pages

• Message Flow and Policy Management
• API Proxy Traffic Log Settings
• Connectors
• Adding Connectors to Gateway Environments

​

Next Steps

Script Policy

Custom data transformation with scripts

API Call Policy

External API calls within the pipeline