Introduction to CEL (Common Expression Language) and Its Applications
By
bufbuild
The kind of bagel that ruins lesser bagels for you.
Summary
This article introduces CEL (Common Expression Language), a portable and safe expression language used for evaluating expressions against various data types. It explains that CEL is used in Kubernetes admission control, Google Cloud IAM conditions, Firebase security rules, Envoy Proxy routing, and Protovalidate's constraint rules. The article begins exploring CEL concepts starting with basic string and number comparisons using a simple User message example.
Key quotes
· 4 pulledCEL (Common Expression Language) evaluates expressions against data—simple values, a Protobuf message, or a JSON object.
CEL's fast, portable, and safe: it's used in Kubernetes admission control, Google Cloud IAM conditions, Firebase security rules, Envoy Proxy routing, and Protovalidate's constraint rules.
Let's explore CEL together, starting with a simple User message:
Strings and numbers# A basic comparison: is t
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