Merge pull request #145 from atc0005/i140-add-support-for-setting-pre…

…ferred-output

Add support for setting preferred output target

nagios.go

@@ -10,6 +10,7 @@ package nagios
 import (
  "errors"
  "fmt"
+ "io"
  "os"
  "runtime/debug"
  "strings"
@@ -188,6 +189,9 @@ type ExitCallBackFunc func() string
 // application, including the most recent error and the final intended plugin
 // state.
 type ExitState struct {
+ // outputSink is the user-specified or fallback target for Nagios plugin
+ // output.
+ outputSink io.Writer
 
  // LastError is the last error encountered which should be reported as
  // part of ending the service check (e.g., "Failed to connect to XYZ to
@@ -348,8 +352,9 @@ func (es *ExitState) ReturnCheckResults() {
 
  es.handlePerformanceData(&output)
 
- // Emit all collected output.
- fmt.Print(output.String())
+ // Emit all collected plugin output using user-specified or fallback
+ // output target.
+ es.emitOutput(output.String())
 
  os.Exit(es.ExitStatusCode)
 }
@@ -384,3 +389,27 @@ func (es *ExitState) AddPerfData(skipValidate bool, pd ...PerformanceData) error
 func (es *ExitState) AddError(err ...error) {
  es.Errors = append(es.Errors, err...)
 }
+
+// SetOutputTarget assigns a target for Nagios plugin output. By default
+// output is emitted to os.Stdout.
+func (es *ExitState) SetOutputTarget(w io.Writer) {
+ // Guard against potential nil argument.
+ if w == nil {
+ es.outputSink = os.Stdout
+ }
+
+ es.outputSink = w
+}
+
+// emitOutput writes final plugin output to the previously set output target.
+// No further modifications to plugin output are performed.
+func (es ExitState) emitOutput(pluginOutput string) {
+
+ // Emit all collected output using user-specified output target. Fall back
+ // to standard output if not set.
+ if es.outputSink == nil {
+ es.outputSink = os.Stdout
+ }
+
+ fmt.Fprint(es.outputSink, pluginOutput)
+}