JSON formatted access logs§

This release introduces the ability to specify a JSON format for access logs.

When defining an access log you can specify ‘format’ as an object defining JSON field name/value pairs, e.g.

{
    "access_log": {
        "path": "/tmp/access.log",
        "format": {
            "remote_addr": "$remote_addr",
            "time_local": "$time_local",
            "request_line": "$request_line",
            "status": "$status",
            "body_bytes_sent": "$body_bytes_sent",
            "header_referer": "$header_referer",
            "header_user_agent": "$header_user_agent"
        }
    }
}

The JSON values support being strings, variables and JavaScript.

OpenTelemetry (OTEL)§

This release includes initial support for OpenTelemtry (OTEL) <https://opentelemetry.io/>

This support has been added via the OpenTelemetry Rust SDK and as such requires cargo/rust to build.

An example configuration looks like

{
   "listeners": {
        "[::1]:8080": {
            "pass": "routes"
        }
    },

    "settings": {
        "telemetry": {
            "batch_size": 20,
            "endpoint": "http://example.com/v1/traces",
            "protocol": "http",
            "sampling_ratio": 1
        }
    },

     "routes": [
        {
            "match": {
                "headers": {
                    "accept": "*text/html*"
                }
            },
            "action": {
                "share": "/usr/share/unit/welcome/welcome.html"
            }
        }, {
            "action": {
                "share": "/usr/share/unit/welcome/welcome.md"
            }
        }
    ]
}

• endpoint

  The endpoint for the OpenTelemetry (OTEL) Collector. This is required.

  The value must be a URL to either a gRPC or HTTP endpoint.

• protocol

  Determines the protocol used to communicate with the endpoint. This is required.

  Can be either “http” or “grpc”.

• batch_size

  Number of spans to cache before triggering a transaction with the configured endpoint. This is optional.

  This allows the user to cache up to N spans before the OpenTelemetry (OTEL) background thread sends spans over the network to the collector.

  Must be a positive integer.

• sampling_ratio

  Percentage of requests to trace. This is optional.

  This allows the user to only trace anywhere from 0% to 100% of requests that hit Unit. In high throughput environments this percentage should be lower. This allows the user to save space in storing span data, and to collect request metrics like time to decode headers and whatnot without storing massive amounts of duplicate superfluous data.

  Must be a positive floating point number.

  This support is disabled by default but can be enabled by passing --otel to ./configure.

Changes to language modules§

• The Perl language module no longer adds a ‘new’ constructor to parsed scripts. It’s not required and could interfere with scripts that were trying to use ‘new’ themselves.

Changes for developers§

• -funsigned-char

  We now compile Unit with -funsigned-char, this ensures we are using the same char type on all platforms (what you get by default varies by platform).

  This is also a first step in getting rid of (mostly at least) our usage of u_char and using char instead, which better aligns with libc interfaces and so on.

Full Changelog§

Changes with Unit 1.34.0                                     19 Dec 2024

    *) Feature: initial OpenTelemetry (OTEL) support. (Disabled by default).

    *) Feature: support for JSON formatted access logs.

    *) Bugfix: tweak the Perl language module to avoid breaking scripts in
               some circumstances.