Types of Hook Rule

Instrument a function

• ImportPath: The import path of the package that contains the function to be instrumented. e.g. net/http.
• Dependencies: is a list of additional dependencies that must be present for this rule to be applied. All dependencies must exist in the project. e.g. `"k8s.io/apimachinery"
• Function: The name of the function to be instrumented, it could be a regular expression to match multiple functions. e.g. .* matches all functions in the package, .*ServeHTTP matches all functions whose name ends with ServeHTTP, and so on.
• ReceiverType: The type of the receiver of the function to be instrumented, it could be a regular expression as well. e.g. .* matches all receiver types in the package, even if the function has no receiver, .* still matches it. .*http.Request matches all functions whose receiver type is http.Request, \\*Client matches all functions whose receiver type is *Client, and so on.
• OnEnter: The name of the function to be called when the instrumented function is called. e.g. clientOnEnter.
• OnExit: The name of the function to be called when the instrumented function returns. e.g. clientOnExit.
• Order: The order of the probe code in the instrumented function. e.g. 0, 1, 2.
• Path: The path to the directory containing the probe code. The path can be either go module url or local file system path, e.g. github.com/foo/bar or /path/to/probe/code.
• Version: The version of the package that contains the function to be instrumented. e.g. [1.0.0,1.1.0), the version range is [1.0.0,1.1.0), which means the version is greater than or equal to 1.0.0 and less than 1.1.0.

![TIP] You can use ".*" of both Function and ReceiverType to match all functions and all receiver types in the specific package.

Add a new file during compiling package

• ImportPath: The import path of the package that contains the function to be instrumented.
• FileName : The name of the file to be added.
• Path: The path to the directory containing the probe code.
• Replace: Replace the file if it already exists, default is false.

Add a new field to a struct

• ImportPath: The import path of the package that contains the struct to be instrumented.
• StructType: The name of the struct to be instrumented.
• FieldName: The name of the field to be added.
• FieldType: The type of the field to be added.