事件：Booking.com观测平台的第四支柱

TL;DR: Metrics, Logs and Traces are three main pillars of observability. At Booking.com, we majorly use Booking.com’s Events , a proprietary solution developed in-house, to generate traces, logs and most of the metrics to fulfil the majority of our observability needs, and we handle tens of millions of Events per second.

TL;DR：指标、日志和跟踪是可观察性的三个主要支柱。在Booking.com，我们主要使用Booking.com的事件，这是一个内部开发的专有解决方案，用于生成跟踪、日志和大部分指标，以满足我们大部分的可观察性需求，我们每秒处理数千万个事件。

Booking.com has distributed services running across a hybrid cloud and each one serves different purpose. For example “Service A” takes care of order processing, “Service B” of inventory etc. All services need observability to examine their availability and performance.

Booking.com在混合云中运行分布式服务，每个服务都有不同的目的。例如，“服务A”负责订单处理，“服务B”负责库存等。所有服务都需要可观察性来检查其可用性和性能。

What are Events at Booking.com?

Booking.com的活动是什么？

The main building block of the Booking.com Events is an Event. An Event is a key-value structure that contains a lot of information about a particular unit of work.

Booking.com活动的主要构建块是事件。事件是一个键值结构，包含有关特定工作单元的大量信息。

For example, an HTTP request would contain a set of all warnings/errors generated during the request processing. It can include performance information, such as the duration of the request, the number of database queries and their latency, also enabled A/B experiments, application-specific information, etc.

例如，一个 HTTP 请求会包含在请求处理过程中生成的所有警告/错误的集合。它可以包括性能信息，如请求的持续时间、数据库查询的数量及其延迟，还有启用的 A/B 实验、应用程序特定信息等。

An Event snippet would look like this

活动片段如下所示

{
"availability_zone" : "london",
"created_epoch": "1660548925.3674",
"Service_name": "service A",
"git_commit_sha": "..", …

}

At a first glance, it may resemble a structured log, though Events have some important differences.

乍一看，它可能类似于结构化日志，但事件有一些重要的区别。

Log messages usually focus on a single info/warn/error message, potentially with some context metadata attached to it. While an Event accumulates inform...