83 lines
2.1 KiB
Go
83 lines
2.1 KiB
Go
package flog
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// NewFilteredRouter returns an initialized FilteredRouter.
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//
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// 'subrouter' is the sub-router that a FilteredRouter will
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// re-Route a 'message' (and 'context') to, but only on the
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// condition that 'filterFn' returns 'true' for the 'message'
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// and 'context' passed to it.
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//
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// An example for 'filterFn' is the following.
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//
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// func filterError(message string, context map[string]interface{})bool) bool {
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// if datum, ok := context["error"]; !ok {
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// return false
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// } else if _, ok := datum.(error); !ok {
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// return false
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// } else {
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// return true
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// }
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// }
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//
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// This func will cause the router it only re-route messages whose context #1 has the
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// key "error" and #2 where the value of the context at key "key" fits the builtin Go
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// 'error' interface.
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//
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// So, for example, for 'filterError' this would pass:
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//
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// context := map[string]interface{}{
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// "apple":1,
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// "banana":2,
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// "cherry":3,
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// "error": errors.New("Something bad happened :-("),
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// }
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//
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// But, again for 'filterError', this would NOT pass:
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//
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// context := map[string]interface{}{
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// "apple":1,
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// "banana":2,
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// "cherry":3,
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// }
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//
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// Also, a rather useless example, but a 'filterFn' that would reject all messages (and
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// contexts) is:
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//
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// func filterRejectAll(message string, context map[string]interface{})bool) bool {
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// return false
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// }
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//
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//
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// And also, another rather useless example, but a 'filterFn' that would allow all messages
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// (and contexts) is:
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//
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// func filterAcceptAll(message string, context map[string]interface{})bool) bool {
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// return true
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// }
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//
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func NewFilteredRouter(subrouter Router, filterFn func(string, map[string]interface{})bool) *FilteredRouter {
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router := FilteredRouter{
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subrouter:subrouter,
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filterFn:filterFn,
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}
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return &router
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}
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// FilteredRouter is a Router that conditionally re-routes or discards a message (and its context).
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type FilteredRouter struct {
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subrouter Router
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filterFn func(string, map[string]interface{})bool
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}
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func (router *FilteredRouter) Route(message string, context map[string]interface{}) error {
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if router.filterFn(message, context) {
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return router.subrouter.Route(message, context)
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}
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return nil
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}
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