Merge lp:~mvo/snappy/snappy-more-errors-15.04 into lp:~snappy-dev/snappy/snappy-moved-to-github

[Michael Vogt]

Improve error reporting for failed hooks.

Improve error reporting for failed hooks. We ran into a hook failure
issue that could only be diagnosed by having the output of the failing
aa-clickhook available.

[John Lenton (chipaca)]

Looks good. Small nit, inline.

review: Approve

[lp:~mvo/snappy/snappy-more-errors-15.04]

441. By Michael Vogt on 2015-06-04

snappy/errors.go: use %q for the output of failed hooks

[Michael Vogt (mvo)]

Thanks, I updated the branch.

review: Approve

=== modified file 'cmd/snappy/cmd_build.go'
=== modified file 'snappy/click.go'
--- snappy/click.go	2015-05-29 14:28:36 +0000
+++ snappy/click.go	2015-06-04 22:12:24 +0000
@@ -92,9 +92,10 @@
 func execHook(execCmd string) (err error) {
 	// the spec says this is passed to the shell
 	cmd := exec.Command("sh", "-c", execCmd)
-	if err = cmd.Run(); err != nil {
+	if output, err := cmd.CombinedOutput(); err != nil {
 		if exitCode, err := helpers.ExitCode(err); err == nil {
 			return &ErrHookFailed{cmd: execCmd,
+				output:   string(output),
 				exitCode: exitCode}
 		}
 		return err

=== modified file 'snappy/errors.go'
--- snappy/errors.go	2015-06-04 13:04:30 +0000
+++ snappy/errors.go	2015-06-04 22:12:24 +0000
@@ -166,11 +166,12 @@
 // ErrHookFailed is returned if a hook command fails
 type ErrHookFailed struct {
 	cmd      string
+	output   string
 	exitCode int
 }
 
 func (e *ErrHookFailed) Error() string {
-	return fmt.Sprintf("hook command %v failed with exit status %d", e.cmd, e.exitCode)
+	return fmt.Sprintf("hook command %v failed with exit status %d (output: %q)", e.cmd, e.exitCode, e.output)
 }
 
 // ErrDataCopyFailed is returned if copying the snap data fialed