// Parses expression in the go language into Failover predicates
func parseExpression(in string) (hpredicate, error) {
p, err := predicate.NewParser(predicate.Def{
Operators: predicate.Operators{
AND: and,
OR: or,
EQ: eq,
NEQ: neq,
LT: lt,
GT: gt,
LE: le,
GE: ge,
},
Functions: map[string]interface{}{
"RequestMethod": requestMethod,
"IsNetworkError": isNetworkError,
"Attempts": attempts,
"ResponseCode": responseCode,
},
})
if err != nil {
return nil, err
}
out, err := p.Parse(in)
if err != nil {
return nil, err
}
pr, ok := out.(hpredicate)
if !ok {
return nil, fmt.Errorf("expected predicate, got %T", out)
}
return pr, nil
}
func parse(expression string, result *match) (matcher, error) {
p, err := predicate.NewParser(predicate.Def{
Functions: map[string]interface{}{
"Host": hostTrieMatcher,
"HostRegexp": hostRegexpMatcher,
"Path": pathTrieMatcher,
"PathRegexp": pathRegexpMatcher,
"Method": methodTrieMatcher,
"MethodRegexp": methodRegexpMatcher,
"Header": headerTrieMatcher,
"HeaderRegexp": headerRegexpMatcher,
},
Operators: predicate.Operators{
AND: newAndMatcher,
},
})
if err != nil {
return nil, err
}
out, err := p.Parse(expression)
if err != nil {
return nil, err
}
m, ok := out.(matcher)
if !ok {
return nil, fmt.Errorf("unknown result type: %T", out)
}
m.setMatch(result)
return m, nil
}