circolog/filtering/filter.go

69 lines
1.6 KiB
Go

// +build !nofilter
package filtering
import (
"fmt"
"os"
"github.com/araddon/qlbridge/datasource"
"github.com/araddon/qlbridge/expr"
"github.com/araddon/qlbridge/value"
"github.com/araddon/qlbridge/vm"
)
type ExprValue struct {
node expr.Node
expression string
}
func (e *ExprValue) String() string {
if e.node != nil {
return e.node.String()
} else {
return "<Empty Expression>"
}
}
func (e *ExprValue) Set(value string) error {
if value == "" {
e.node = nil
e.expression = value
return nil
}
ast, err := expr.ParseExpression(value)
if err != nil {
return err
}
e.node = ast
e.expression = value
return nil
}
// Validate answers the question whether to include a log line or not.
func (e *ExprValue) Validate(logLine map[string]interface{}) bool {
if e.node == nil {
return true
}
line := translateMap(logLine)
context := datasource.NewContextSimpleNative(line)
val, ok := vm.Eval(context, e.node)
if !ok || val == nil { // errors when evaluating
return false
}
if bv, isBool := val.(value.BoolValue); isBool {
return bv.Val()
}
fmt.Fprintln(os.Stderr, "WARNING: The 'where' expression doesn't return a boolean")
return false
}
func translateMap(lineInput map[string]interface{}) map[string]interface{} {
lineOutput := make(map[string]interface{})
lineOutput["prog"] = lineInput["app_name"]
lineOutput["msg"] = lineInput["message"]
lineOutput["facility"] = lineInput["facility"]
lineOutput["host"] = lineInput["hostname"]
lineOutput["time"] = lineInput["timestamp"]
lineOutput["sev"] = lineInput["severity"]
return lineOutput
}