func checkPackages()

in integration_test/agents/agents.go [432:482]
51 lines of code
16 McCabe index (conditional complexity)

func checkPackages(ctx context.Context, logger *log.Logger, vm *gce.VM, pkgs []string, installed bool) error {
	errPrefix := ""
	if installed {
		errPrefix = "not "
	}
	if gce.IsWindows(vm.ImageSpec) {
		output, err := gce.RunRemotely(ctx, logger, vm, "googet installed")
		if err != nil {
			return err
		}
		for _, pkg := range pkgs {
			// Look for the package name in the output. \b means word boundary.
			expr := `\b` + pkg + `\b`
			re, err := regexp.Compile(expr)
			if err != nil {
				return fmt.Errorf("regexp %q failed to compile: %v", expr, err)
			}
			if m := re.FindString(output.Stdout); (m == "") == installed {
				return fmt.Errorf("package %q was unexpectedly %sinstalled", pkg, errPrefix)
			}
		}
		// Success: the expected set of packages was found in the output of "googet installed".
		return nil
	}
	for _, pkg := range pkgs {
		cmd := ""
		if IsRPMBased(vm.ImageSpec) {
			cmd = fmt.Sprintf("rpm --query %s", pkg)
			if !installed {
				cmd = "! " + cmd
			}
		} else if strings.HasPrefix(vm.ImageSpec, "debian-cloud") ||
			strings.HasPrefix(vm.ImageSpec, "ubuntu-os-cloud") {
			// dpkg's package states are documented in "man 1 dpkg".
			// "config-files" means that the package is not installed but its config files
			// are still on the system. Accepting both that and "not-installed" is more
			// future-proof than just accepting "config-files".
			cmd = fmt.Sprintf(
				`(dpkg-query --show '--showformat=${db:Status-Status}' %s || echo 'not-installed') | grep --extended-regexp '(not-installed)|(config-files)'`, pkg)
			if installed {
				cmd = "! (" + cmd + ")"
			}
		} else {
			return fmt.Errorf("checkPackages() does not support image spec: %s", vm.ImageSpec)
		}
		if _, err := gce.RunRemotely(ctx, logger, vm, cmd); err != nil {
			return fmt.Errorf("command could not be run or %q was unexpectedly %sinstalled. err: %v", pkg, errPrefix, err)
		}
	}
	return nil
}