helper.go

package cmd

import (
	"fmt"
	"io"
	"os"
	"os/exec"
	"strings"
	"time"

	"github.com/deis/workflow-e2e/tests/model"
	"github.com/deis/workflow-e2e/tests/settings"

	"github.com/onsi/ginkgo"
	"github.com/onsi/gomega"
	"github.com/onsi/gomega/gexec"
)

// The functions in this file implement a generic command execution and inspection framework.

// Execute executes the command generated by fmt.Sprintf(cmdLine, args...) and returns its output.
func Execute(cmdLine string, args ...interface{}) (string, error) {
	var cmd *exec.Cmd
	shCommand := fmt.Sprintf(cmdLine, args...)

	if settings.Debug {
		fmt.Println(shCommand)
	}

	cmd = exec.Command("/bin/sh", "-c", shCommand)
	outputBytes, err := cmd.CombinedOutput()

	output := string(outputBytes)

	if settings.Debug {
		fmt.Println(output)
	}

	return output, err
}

// Start executes the provided command (often a `deis` command of some sort) as the specified user
// (by selecting the corresponding profile). Optional arguments may also be supplied that will be
// substituted into the provided command using fmt.Sprintf(...).
func Start(cmdLine string, user *model.User, args ...interface{}) (*gexec.Session, error) {
	if user != nil {
		envVars := append(os.Environ(), fmt.Sprintf("DEIS_PROFILE=%s", user.Username))
		ourCommand := model.Cmd{Env: envVars, CommandLineString: fmt.Sprintf(cmdLine, args...)}
		return StartCmd(ourCommand)
	}
	ourCommand := model.Cmd{Env: os.Environ(), CommandLineString: fmt.Sprintf(cmdLine, args...)}
	return StartCmd(ourCommand)
}

// StartCmd executes the provided model.Command. It is used primarily by the Start function
// (above), but is also used directly in scenarios where tests must execute fine-grained control
// over the environment in which the command will be executed.
func StartCmd(command model.Cmd) (*gexec.Session, error) {
	execCmd := exec.Command("/bin/sh", "-c", command.CommandLineString)
	execCmd.Env = command.Env
	io.WriteString(ginkgo.GinkgoWriter, fmt.Sprintf("$ %s\n", command.CommandLineString))
	return gexec.Start(execCmd, ginkgo.GinkgoWriter, ginkgo.GinkgoWriter)
}

// Retry runs the provided <cmd> repeatedly, once a second up to the
// supplied <timeout> until the <cmd> result contains the <expectedResult>
// An example use of this utility would be curl-ing a url and waiting
// until the response code matches the expected response.
// TODO: https://github.com/deis/workflow-e2e/issues/240
func Retry(command model.Cmd, expectedResult string, timeout int) bool {
	var result string
	fmt.Fprintf(ginkgo.GinkgoWriter, "Waiting up to %d seconds for `%s` to return %s...\n", timeout, command.CommandLineString, expectedResult)
	for i := 0; i < timeout; i++ {
		sess, err := StartCmd(command)
		gomega.Expect(err).NotTo(gomega.HaveOccurred())
		result = string(sess.Wait().Out.Contents())
		if strings.Contains(result, expectedResult) {
			return true
		}
		time.Sleep(1 * time.Second)
	}
	fmt.Fprintf(ginkgo.GinkgoWriter, "FAIL: '%s' does not match expected result of '%s'\n", result, expectedResult)
	return false
}

// RetryUntilResult runs the provided cmd repeatedly, once every period,
// up to the supplied timeout until the cmd result matches the supplied
// expectedCmdResult
func RetryUntilResult(command model.Cmd, expectedCmdResult model.CmdResult, period, timeout time.Duration) bool {
	var actualCmdResult model.CmdResult

	fmt.Fprintf(ginkgo.GinkgoWriter,
		"Waiting up to %d seconds for `%s` to return expected cmdResult %s...\n",
		int(timeout.Seconds()), command.CommandLineString, expectedCmdResult.String())

	tck := time.NewTicker(period)
	tmr := time.NewTimer(timeout)
	defer tck.Stop()
	defer tmr.Stop()
	for {
		select {
		case <-tck.C:
			sess, err := StartCmd(command)
			gomega.Expect(err).NotTo(gomega.HaveOccurred())
			sessWait := sess.Wait()
			actualCmdResult = model.CmdResult{
				Out:      sessWait.Out.Contents(),
				Err:      sessWait.Err.Contents(),
				ExitCode: sessWait.ExitCode(),
			}
			if actualCmdResult.Satisfies(expectedCmdResult) {
				return true
			}
		case <-tmr.C:
			fmt.Fprintf(ginkgo.GinkgoWriter, "FAIL: Actual cmdResult '%v' does not match expected cmdResult '%v'\n", actualCmdResult, expectedCmdResult)
			return false
		}
	}
}