Parameter meaning: The auth parameter is etcd root path, and the code parameter is expr execution expression.
Injection object: Currently, the objects injected by expr include: param, proxy, rootcoord, querycoord, datacoord, quernode, datanode. You can use this tool to get the running value of the object.
Usage example: 1. Get a configuration: param.CommonCfg.GracefulTime.GetValue() 2. Get a property value in the proxy object: proxy.address 3. Determine whether a graph exists in the datanode: datanode.flowgraphManager.HasFlowgraph("aaa")
Limitations: 1. Variables cannot be modified. 2. Methods with non-basic type parameters cannot be executed. 3. Functions with multiple return values cannot be chained.