Execute a simple query

This API queries the document at /data/system/main by default (however, you can configure OPA to use a different path to serve these queries). That document defines the response. For example, use the following in PUT /v1/policies/{path}) to define a rule that will produce a value for the /data/system/main document:

package system
main = msg {
  msg := sprintf("hello, %v", input.user)
}

The server will return a not found (404) response if /data/system/main is undefined.