Golang Step.Perform方法代碼示例

		logger = lagertest.NewTestLogger("test")
	})

	JustBeforeEach(func() {
		step = steps.NewEmitProgress(subStep, startMessage, successMessage, failureMessage, fakeStreamer, logger)
	})

	Context("running", func() {
		Context("when there is a start message", func() {
			BeforeEach(func() {
				startMessage = "STARTING"
			})

			It("should emit the start message before performing", func() {
				err := step.Perform()
				Expect(err).NotTo(HaveOccurred())
				Expect(stdoutBuffer.String()).To(Equal("STARTING\nRUNNING\n"))
			})
		})

		Context("when there is no start or success message", func() {
			It("should not emit the start message (i.e. a newline) before performing", func() {
				err := step.Perform()
				Expect(err).NotTo(HaveOccurred())
				Expect(stdoutBuffer.String()).To(Equal("RUNNING\n"))
			})
		})

		Context("when the substep succeeds and there is a success message", func() {
			BeforeEach(func() {

				<-doneChan
				return nil
			}
			checkFunc = func() steps.Step {
				return fakeStep
			}

		})

		AfterEach(func() {
			step.Cancel()
		})

		It("throttles concurrent health check", func() {
			for i := 0; i < 5; i++ {
				go step.Perform()
			}

			Consistently(fakeStep.PerformCallCount).Should(Equal(0))
			clock.Increment(501 * time.Millisecond)

			Eventually(func() int {
				return len(throttleChan)
			}).Should(Equal(numOfConcurrentMonitorSteps))
			Consistently(func() int {
				return len(throttleChan)
			}).Should(Equal(numOfConcurrentMonitorSteps))

			Eventually(fakeStep.PerformCallCount).Should(Equal(numOfConcurrentMonitorSteps))

			doneChan <- struct{}{}

				thingHappened <- true
				return nil
			},
			CancelStub: func() {
				cancelled <- true
			},
		}
	})

	Describe("Perform", func() {
		JustBeforeEach(func() {
			step = steps.NewCodependent([]steps.Step{subStep1, subStep2}, errorOnExit)
		})

		It("performs its substeps in parallel", func() {
			err := step.Perform()
			Expect(err).NotTo(HaveOccurred())

			Eventually(thingHappened).Should(Receive())
			Eventually(thingHappened).Should(Receive())
		})

		Context("when one of the substeps fails", func() {
			disaster := errors.New("oh no!")

			BeforeEach(func() {
				subStep1 = &fakes.FakeStep{
					PerformStub: func() error {
						return disaster
					},
				}

				return nil
			},
			CancelStub: func() {
				cancelled <- true
			},
		}
	})

	JustBeforeEach(func() {
		step = steps.NewParallel([]steps.Step{subStep1, subStep2})
	})

	It("performs its substeps in parallel", func(done Done) {
		defer close(done)

		err := step.Perform()
		Expect(err).NotTo(HaveOccurred())

		Eventually(thingHappened).Should(Receive())
		Eventually(thingHappened).Should(Receive())
	}, 2)

	Context("when one of the substeps fails", func() {
		disaster := errors.New("oh no!")
		var triggerStep2 chan struct{}
		var step2Completed chan struct{}

		BeforeEach(func() {
			triggerStep2 = make(chan struct{})
			step2Completed = make(chan struct{})

			container,
			runAction,
			fakeStreamer,
			logger,
			externalIP,
			portMappings,
			exportNetworkEnvVars,
			fakeClock,
		)
	})

	Describe("Perform", func() {
		var stepErr error

		JustBeforeEach(func() {
			stepErr = step.Perform()
		})

		Context("when the script succeeds", func() {
			BeforeEach(func() {
				spawnedProcess.WaitReturns(0, nil)
			})

			It("does not return an error", func() {
				Expect(stepErr).NotTo(HaveOccurred())
			})

			It("executes the command in the passed-in container", func() {
				ranHandle, spec, _ := gardenClient.Connection.RunArgsForCall(0)
				Expect(ranHandle).To(Equal(handle))
				Expect(spec.Path).To(Equal("sudo"))

func (store *GardenStore) runStepProcess(
	logger lager.Logger,
	step steps.Step,
	hasStartedRunning <-chan struct{},
	gardenContainer garden.Container,
	guid string,
) {
	process := ifrit.Invoke(ifrit.RunFunc(func(signals <-chan os.Signal, ready chan<- struct{}) error {
		logger := logger.Session("run-step-process")
		logger.Info("started")
		defer logger.Info("finished")
		seqComplete := make(chan error)

		close(ready)

		go func() {
			seqComplete <- step.Perform()
		}()

		result := executor.ContainerRunResult{}

		toldToStop := false

	OUTER_LOOP:
		for {
			select {
			case <-signals:
				signals = nil
				toldToStop = true

				logger.Info("signaled")
				step.Cancel()

			case <-hasStartedRunning:
				hasStartedRunning = nil
				logger.Info("transitioning-to-running")
				err := store.transitionToRunning(logger, gardenContainer)
				if err != nil {
					logger.Error("failed-transitioning-to-running", err)
					result.Failed = true
					result.FailureReason = err.Error()
					break OUTER_LOOP
				}
				logger.Info("succeeded-transitioning-to-running")

			case err := <-seqComplete:
				if err == nil {
					logger.Info("step-finished-normally")
				} else if toldToStop {
					logger.Info("step-cancelled")
					result.Stopped = true
				} else {
					logger.Info("step-finished-with-error", lager.Data{"error": err.Error()})
					result.Failed = true
					result.FailureReason = err.Error()
				}

				break OUTER_LOOP
			}
		}

		logger.Info("transitioning-to-complete")
		err := store.transitionToComplete(logger, gardenContainer, result)
		if err != nil {
			logger.Error("failed-transitioning-to-complete", err)
			return nil
		}
		logger.Info("succeeded-transitioning-to-complete")

		return nil
	}))

	store.processesL.Lock()
	store.runningProcesses[guid] = process
	numProcesses := len(store.runningProcesses)
	store.processesL.Unlock()

	logger.Info("stored-step-process", lager.Data{"num-step-processes": numProcesses})
}

		JustBeforeEach(func() {
			container, err := gardenClient.Create(garden.ContainerSpec{
				Handle: handle,
			})
			Expect(err).NotTo(HaveOccurred())

			step = steps.NewDownload(
				container,
				downloadAction,
				cache,
				rateLimiter,
				fakeStreamer,
				logger,
			)

			stepErr = step.Perform()
		})

		var tarReader *tar.Reader

		It("downloads via the cache with a tar transformer", func() {
			Expect(cache.FetchCallCount()).To(Equal(1))

			url, cacheKey, transformer, cancelChan := cache.FetchArgsForCall(0)
			Expect(url.Host).To(ContainSubstring("mr_jones"))
			Expect(cacheKey).To(Equal("the-cache-key"))
			Expect(cancelChan).NotTo(BeNil())

			tVal := reflect.ValueOf(transformer)
			expectedVal := reflect.ValueOf(cacheddownloader.TarTransform)