ImageMagick 教程

---

注意：此内容仅适用于 Cloud Run functions，即原 Cloud Functions (第 2 代)。

如需了解本文档的第 1 代版本，请参阅 ImageMagick 教程（第 1 代）。

本教程演示了如何使用 Cloud Run functions、Vision API 和 ImageMagick 检测上传到 Cloud Storage 存储桶的令人反感的图片并对其进行模糊处理。

注意：虽然本教程演示的是如何对图片进行模糊处理，但 ImageMagick 的功能远不止图片模糊处理。您也可以考虑将 Node.js 封装容器用于在 npm 上找到的 ImageMagick。

目标

• 部署存储触发的 CloudEvent 函数。
• 使用 Vision API 检测暴力或成人内容。
• 使用 ImageMagick 对令人反感的图片进行模糊处理。
• 上传一张肉食僵尸的图片来测试函数。

费用

在本文档中，您将使用 Google Cloud 的以下收费组件：

• Cloud Run functions
• Cloud Storage
• Cloud Vision
• Cloud Build
• Pub/Sub
• Artifact Registry
• Eventarc
• Cloud Logging

For details, see Cloud Run functions pricing.

您可使用价格计算器根据您的预计使用情况来估算费用。 Google Cloud 新用户可能有资格申请免费试用。

准备工作

1. 登录您的 Google Cloud 账号。如果您是 Google Cloud 新手，请创建一个账号来评估我们的产品在实际场景中的表现。新客户还可获享 $300 赠金，用于运行、测试和部署工作负载。

2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

3. 确保您的 Google Cloud 项目已启用结算功能。

4. Enable the Cloud Functions, Cloud Build, Artifact Registry, Eventarc, Cloud Storage, Cloud Vision, Logging, and Pub/Sub APIs.

   Enable the APIs

5. Install the Google Cloud CLI.

6. To initialize the gcloud CLI, run the following command:

   gcloud init

7. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

8. 确保您的 Google Cloud 项目已启用结算功能。

9. Enable the Cloud Functions, Cloud Build, Artifact Registry, Eventarc, Cloud Storage, Cloud Vision, Logging, and Pub/Sub APIs.

   Enable the APIs

10. Install the Google Cloud CLI.

11. To initialize the gcloud CLI, run the following command:

    gcloud init

如果您已经安装 gcloud CLI，请运行以下命令进行更新：

gcloud components update

12. 准备开发环境。

    Node.js

    转到 Node.js 设置指南

    Python

    转到 Python 设置指南

    Go

    转到 Go 设置指南

    Java

    转到 Java 设置指南

直观呈现数据流

ImageMagick 教程应用中的数据流涉及以下几个步骤：

1. 将图片上传到 Cloud Storage 存储桶。
2. Cloud Run functions 函数使用 Cloud Vision API 分析图片。
3. 如果检测到暴力或成人内容，Cloud Run functions 函数会使用 ImageMagick 对图片进行模糊处理。
4. 经过模糊处理的图片会上传到其他 Cloud Storage 存储桶以供使用。

准备应用

1. 创建一个区域级 Cloud Storage 存储桶以上传图片，其中 YOUR_INPUT_BUCKET_NAME 是全局唯一的存储桶名称，REGION 是您计划在其中部署函数的区域：

   gcloud storage buckets create gs://YOUR_INPUT_BUCKET_NAME --location=REGION

2. 创建一个区域级 Cloud Storage 存储桶以接收经过模糊处理的图片，其中 YOUR_OUTPUT_BUCKET_NAME 是全局唯一的存储桶名称，REGION 是您计划在其中部署函数的区域：

   gcloud storage buckets create gs://YOUR_OUTPUT_BUCKET_NAME --location=REGION

3. 将示例应用代码库克隆到本地机器：

   Node.js

   git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

   或者，您也可以下载该示例的 zip 文件并将其解压缩。

   Python

   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

   或者，您也可以下载该示例的 zip 文件并将其解压缩。

   Go

   git clone https://github.com/GoogleCloudPlatform/golang-samples.git

   或者，您也可以下载该示例的 zip 文件并将其解压缩。

   Java

   git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

   或者，您也可以下载该示例的 zip 文件并将其解压缩。

4. 切换到包含 Cloud Run functions 示例代码的目录：

   Node.js

   cd nodejs-docs-samples/functions/v2/imagemagick/

   Python

   cd python-docs-samples/functions/v2/imagemagick/

   Go

   cd golang-samples/functions/functionsv2/imagemagick/

   Java

   cd java-docs-samples/functions/v2/imagemagick/

了解代码

ImageMagick 示例包含依赖项和两个不同的函数。第一个函数分析图片，如果图片包含暴力或成人内容，第二个函数会对图片进行模糊处理。

导入依赖项

应用必须导入多个依赖项才能与 Google Cloud 服务、ImageMagick 和文件系统进行交互：

对于大多数运行时，ImageMagick 及其命令行工具 convert 默认包含在 Cloud Run functions 执行环境中。对于 PHP，您可能需要进行一些手动配置。请注意，Cloud Run functions 不支持安装自定义系统级软件包。

Node.js

const functions = require('@google-cloud/functions-framework');
const gm = require('gm').subClass({imageMagick: true});
const fs = require('fs').promises;
const path = require('path');
const vision = require('@google-cloud/vision');

const {Storage} = require('@google-cloud/storage');
const storage = new Storage();
const client = new vision.ImageAnnotatorClient();

const {BLURRED_BUCKET_NAME} = process.env;

Python

import os
import tempfile

import functions_framework
from google.cloud import storage, vision
from wand.image import Image

storage_client = storage.Client()
vision_client = vision.ImageAnnotatorClient()

Go

// Package imagemagick contains an example of using ImageMagick to process a
// file uploaded to Cloud Storage.
package imagemagick

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"
	"os/exec"

	"cloud.google.com/go/storage"
	vision "cloud.google.com/go/vision/apiv1"
	"cloud.google.com/go/vision/v2/apiv1/visionpb"
	"github.com/GoogleCloudPlatform/functions-framework-go/functions"
	cloudevents "github.com/cloudevents/sdk-go/v2"
	"github.com/googleapis/google-cloudevents-go/cloud/storagedata"
	"google.golang.org/protobuf/encoding/protojson"
)

// Global API clients used across function invocations.
var (
	storageClient *storage.Client
	visionClient  *vision.ImageAnnotatorClient
)

func init() {
	// Declare a separate err variable to avoid shadowing the client variables.
	var err error

	bgctx := context.Background()
	storageClient, err = storage.NewClient(bgctx)
	if err != nil {
		log.Fatalf("storage.NewClient: %v", err)
	}

	visionClient, err = vision.NewImageAnnotatorClient(bgctx)
	if err != nil {
		log.Fatalf("vision.NewAnnotatorClient: %v", err)
	}
	functions.CloudEvent("blur-offensive-images", blurOffensiveImages)
}

Java

import com.google.cloud.functions.CloudEventsFunction;
import com.google.cloud.storage.Blob;
import com.google.cloud.storage.BlobId;
import com.google.cloud.storage.BlobInfo;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import com.google.cloud.vision.v1.AnnotateImageRequest;
import com.google.cloud.vision.v1.AnnotateImageResponse;
import com.google.cloud.vision.v1.BatchAnnotateImagesResponse;
import com.google.cloud.vision.v1.Feature;
import com.google.cloud.vision.v1.Feature.Type;
import com.google.cloud.vision.v1.Image;
import com.google.cloud.vision.v1.ImageAnnotatorClient;
import com.google.cloud.vision.v1.ImageSource;
import com.google.cloud.vision.v1.SafeSearchAnnotation;
import com.google.events.cloud.storage.v1.StorageObjectData;
import com.google.protobuf.InvalidProtocolBufferException;
import com.google.protobuf.util.JsonFormat;
import io.cloudevents.CloudEvent;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ImageMagick implements CloudEventsFunction {

  private static Storage storage = StorageOptions.getDefaultInstance().getService();
  private static final String BLURRED_BUCKET_NAME = System.getenv("BLURRED_BUCKET_NAME");
  private static final Logger logger = Logger.getLogger(ImageMagick.class.getName());
}

分析图片

当图片上传到您为图片输入创建的 Cloud Storage 存储桶时，系统会调用以下函数。该函数使用 Vision API 检测上传的图片中的暴力或成人内容。

Node.js

// Blurs uploaded images that are flagged as Adult or Violence.
functions.cloudEvent('blurOffensiveImages', async cloudEvent => {
  // This event represents the triggering Cloud Storage object.
  const bucket = cloudEvent.data.bucket;
  const name = cloudEvent.data.name;
  const file = storage.bucket(bucket).file(name);
  const filePath = `gs://${bucket}/${name}`;

  console.log(`Analyzing ${file.name}.`);

  try {
    const [result] = await client.safeSearchDetection(filePath);
    const detections = result.safeSearchAnnotation || {};

    if (
      // Levels are defined in https://cloud.google.com/vision/docs/reference/rest/v1/AnnotateImageResponse#likelihood
      detections.adult === 'VERY_LIKELY' ||
      detections.violence === 'VERY_LIKELY'
    ) {
      console.log(`Detected ${file.name} as inappropriate.`);
      return await blurImage(file, BLURRED_BUCKET_NAME);
    } else {
      console.log(`Detected ${file.name} as OK.`);
    }
  } catch (err) {
    console.error(`Failed to analyze ${file.name}.`, err);
    throw err;
  }
});

Python

# Blurs uploaded images that are flagged as Adult or Violent imagery.
@functions_framework.cloud_event
def blur_offensive_images(cloud_event):
    file_data = cloud_event.data

    file_name = file_data["name"]
    bucket_name = file_data["bucket"]

    blob = storage_client.bucket(bucket_name).get_blob(file_name)
    blob_uri = f"gs://{bucket_name}/{file_name}"
    blob_source = vision.Image(source=vision.ImageSource(gcs_image_uri=blob_uri))

    # Ignore already-blurred files
    if file_name.startswith("blurred-"):
        print(f"The image {file_name} is already blurred.")
        return

    print(f"Analyzing {file_name}.")

    result = vision_client.safe_search_detection(image=blob_source)
    detected = result.safe_search_annotation

    # Process image
    # 5 maps to VERY_LIKELY
    if detected.adult == 5 or detected.violence == 5:
        print(f"The image {file_name} was detected as inappropriate.")
        return __blur_image(blob)
    else:
        print(f"The image {file_name} was detected as OK.")

Go

// blurOffensiveImages blurs offensive images uploaded to GCS.
func blurOffensiveImages(ctx context.Context, e cloudevents.Event) error {
	outputBucket := os.Getenv("BLURRED_BUCKET_NAME")
	if outputBucket == "" {
		return errors.New("environment variable BLURRED_BUCKET_NAME must be set")
	}

	var gcsEvent storagedata.StorageObjectData
	if err := protojson.Unmarshal(e.Data(), &gcsEvent); err != nil {
		return fmt.Errorf("protojson.Unmarshal: failed to decode event data: %w", err)
	}
	img := vision.NewImageFromURI(fmt.Sprintf("gs://%s/%s", gcsEvent.GetBucket(), gcsEvent.GetName()))

	resp, err := visionClient.DetectSafeSearch(ctx, img, nil)
	if err != nil {
		return fmt.Errorf("visionClient.DetectSafeSearch: %w", err)
	}

	if resp.GetAdult() == visionpb.Likelihood_VERY_LIKELY ||
		resp.GetViolence() == visionpb.Likelihood_VERY_LIKELY {
		return blur(ctx, gcsEvent.Bucket, outputBucket, gcsEvent.Name)
	}
	log.Printf("The image %q was detected as OK.", gcsEvent.Name)
	return nil
}

Java

@Override
// Blurs uploaded images that are flagged as Adult or Violence.
public void accept(CloudEvent event) throws InvalidProtocolBufferException {
  // Extract the GCS Event data from the CloudEvent's data payload.
  StorageObjectData data = getEventData(event);
  // Validate parameters
  if (data == null) {
    logger.severe("Error: Malformed GCS event.");
    return;
  }

  BlobInfo blobInfo = BlobInfo.newBuilder(data.getBucket(), data.getName()).build();

  // Construct URI to GCS bucket and file.
  String gcsPath = String.format("gs://%s/%s", data.getBucket(), data.getName());
  logger.info(String.format("Analyzing %s", data.getName()));

  // Construct request.
  ImageSource imgSource = ImageSource.newBuilder().setImageUri(gcsPath).build();
  Image img = Image.newBuilder().setSource(imgSource).build();
  Feature feature = Feature.newBuilder().setType(Type.SAFE_SEARCH_DETECTION).build();
  AnnotateImageRequest request = AnnotateImageRequest
      .newBuilder()
      .addFeatures(feature)
      .setImage(img)
      .build();
  List<AnnotateImageRequest> requests = List.of(request);

  // Send request to the Vision API.
  try (ImageAnnotatorClient client = ImageAnnotatorClient.create()) {
    BatchAnnotateImagesResponse response = client.batchAnnotateImages(requests);
    List<AnnotateImageResponse> responses = response.getResponsesList();
    for (AnnotateImageResponse res : responses) {
      if (res.hasError()) {
        logger.info(String.format("Error: %s", res.getError().getMessage()));
        return;
      }
      // Get Safe Search Annotations
      SafeSearchAnnotation annotation = res.getSafeSearchAnnotation();
      if (annotation.getAdultValue() == 5 || annotation.getViolenceValue() == 5) {
        logger.info(String.format("Detected %s as inappropriate.", data.getName()));
        blur(blobInfo);
      } else {
        logger.info(String.format("Detected %s as OK.", data.getName()));
      }
    }
  } catch (IOException e) {
    logger.log(Level.SEVERE, "Error with Vision API: " + e.getMessage(), e);
  }
}

对图片进行模糊处理

当在上传的图片中检测到暴力或成人内容时，系统将调用以下函数。该函数会下载令人反感的图片，使用 ImageMagick 对图片进行模糊处理，然后将经过模糊处理的图片上传到输出存储桶。

Node.js

// Blurs the given file using ImageMagick, and uploads it to another bucket.
const blurImage = async (file, blurredBucketName) => {
  const tempLocalPath = `/tmp/${path.parse(file.name).base}`;

  // Download file from bucket.
  try {
    await file.download({destination: tempLocalPath});

    console.log(`Downloaded ${file.name} to ${tempLocalPath}.`);
  } catch (err) {
    throw new Error(`File download failed: ${err}`);
  }

  await new Promise((resolve, reject) => {
    gm(tempLocalPath)
      .blur(0, 16)
      .write(tempLocalPath, (err, stdout) => {
        if (err) {
          console.error('Failed to blur image.', err);
          reject(err);
        } else {
          console.log(`Blurred image: ${file.name}`);
          resolve(stdout);
        }
      });
  });

  // Upload result to a different bucket, to avoid re-triggering this function.
  const blurredBucket = storage.bucket(blurredBucketName);

  // Upload the Blurred image back into the bucket.
  const gcsPath = `gs://${blurredBucketName}/${file.name}`;
  try {
    await blurredBucket.upload(tempLocalPath, {destination: file.name});
    console.log(`Uploaded blurred image to: ${gcsPath}`);
  } catch (err) {
    throw new Error(`Unable to upload blurred image to ${gcsPath}: ${err}`);
  }

  // Delete the temporary file.
  return fs.unlink(tempLocalPath);
};

Python

# Blurs the given file using ImageMagick.
def __blur_image(current_blob):
    file_name = current_blob.name
    _, temp_local_filename = tempfile.mkstemp()

    # Download file from bucket.
    current_blob.download_to_filename(temp_local_filename)
    print(f"Image {file_name} was downloaded to {temp_local_filename}.")

    # Blur the image using ImageMagick.
    with Image(filename=temp_local_filename) as image:
        image.resize(*image.size, blur=16, filter="hamming")
        image.save(filename=temp_local_filename)

    print(f"Image {file_name} was blurred.")

    # Upload result to a second bucket, to avoid re-triggering the function.
    # You could instead re-upload it to the same bucket + tell your function
    # to ignore files marked as blurred (e.g. those with a "blurred" prefix)
    blur_bucket_name = os.getenv("BLURRED_BUCKET_NAME")
    blur_bucket = storage_client.bucket(blur_bucket_name)
    new_blob = blur_bucket.blob(file_name)
    new_blob.upload_from_filename(temp_local_filename)
    print(f"Blurred image uploaded to: gs://{blur_bucket_name}/{file_name}")

    # Delete the temporary file.
    os.remove(temp_local_filename)

Go

// blur blurs the image stored at gs://inputBucket/name and stores the result in
// gs://outputBucket/name.
func blur(ctx context.Context, inputBucket, outputBucket, name string) error {
	inputBlob := storageClient.Bucket(inputBucket).Object(name)
	r, err := inputBlob.NewReader(ctx)
	if err != nil {
		return fmt.Errorf("inputBlob.NewReader: %w", err)
	}

	outputBlob := storageClient.Bucket(outputBucket).Object(name)
	w := outputBlob.NewWriter(ctx)
	defer w.Close()

	// Use - as input and output to use stdin and stdout.
	cmd := exec.Command("convert", "-", "-blur", "0x8", "-")
	cmd.Stdin = r
	cmd.Stdout = w

	if err := cmd.Run(); err != nil {
		return fmt.Errorf("cmd.Run: %w", err)
	}

	if err := w.Close(); err != nil {
		return fmt.Errorf("failed to write output file: %w", err)
	}
	log.Printf("Blurred image uploaded to gs://%s/%s", outputBlob.BucketName(), outputBlob.ObjectName())

	return nil
}

Java

// Blurs the file described by blobInfo using ImageMagick,
// and uploads it to the blurred bucket.
private static void blur(BlobInfo blobInfo) throws IOException {
  String bucketName = blobInfo.getBucket();
  String fileName = blobInfo.getName();

  // Download image
  Blob blob = storage.get(BlobId.of(bucketName, fileName));
  Path download = Paths.get("/tmp/", fileName);
  blob.downloadTo(download);

  // Construct the command.
  Path upload = Paths.get("/tmp/", "blurred-" + fileName);
  List<String> args = List.of("convert", download.toString(), "-blur", "0x8", upload.toString());
  try {
    ProcessBuilder pb = new ProcessBuilder(args);
    Process process = pb.start();
    process.waitFor();
  } catch (Exception e) {
    logger.info(String.format("Error: %s", e.getMessage()));
  }

  // Upload image to blurred bucket.
  BlobId blurredBlobId = BlobId.of(BLURRED_BUCKET_NAME, fileName);
  BlobInfo blurredBlobInfo = BlobInfo
      .newBuilder(blurredBlobId)
      .setContentType(blob.getContentType())
      .build();

  byte[] blurredFile = Files.readAllBytes(upload);
  storage.create(blurredBlobInfo, blurredFile);
  logger.info(
      String.format("Blurred image uploaded to: gs://%s/%s", BLURRED_BUCKET_NAME, fileName));

  // Remove images from fileSystem
  Files.delete(download);
  Files.delete(upload);
}

部署该函数

如需使用存储触发器部署 Cloud Run functions 函数，请在包含示例代码（如果是 Java，则为 pom.xml 文件）的目录中运行以下命令：

Node.js

gcloud functions deploy nodejs-blur-function \
--gen2 \
--runtime=RUNTIME \
--region=REGION \
--source=. \
--entry-point=blurOffensiveImages \
--trigger-bucket=YOUR_INPUT_BUCKET_NAME \
--set-env-vars=BLURRED_BUCKET_NAME=YOUR_OUTPUT_BUCKET_NAME

Python

gcloud functions deploy python-blur-function \
--gen2 \
--runtime=RUNTIME \
--region=REGION \
--source=. \
--entry-point=blur_offensive_images \
--trigger-bucket=YOUR_INPUT_BUCKET_NAME \
--set-env-vars=BLURRED_BUCKET_NAME=YOUR_OUTPUT_BUCKET_NAME

Go

gcloud functions deploy go-blur-function \
--gen2 \
--runtime=RUNTIME \
--region=REGION \
--source=. \
--entry-point=blur-offensive-images \
--trigger-bucket=YOUR_INPUT_BUCKET_NAME \
--set-env-vars=BLURRED_BUCKET_NAME=YOUR_OUTPUT_BUCKET_NAME

Java

gcloud functions deploy java-blur-function \
--gen2 \
--runtime=RUNTIME \
--region=REGION \
--source=. \
--entry-point=functions.ImageMagick \
--trigger-bucket=YOUR_INPUT_BUCKET_NAME \
--set-env-vars=BLURRED_BUCKET_NAME=YOUR_OUTPUT_BUCKET_NAME

替换以下内容：

• RUNTIME：基于 Ubuntu 18.04 或更高版本的运行时
• REGION：要在其中部署函数的 Google Cloud 区域的名称（例如 us-west1）。
• YOUR_INPUT_BUCKET_NAME：用于上传图片的 Cloud Storage 存储桶的名称。
• YOUR_OUTPUT_BUCKET_NAME：经过模糊处理的图片应保存到的存储桶的名称。

部署 Cloud Run functions 时，请仅指定不含前导 gs:// 的存储桶名称；例如 --trigger-event-filters="bucket=my-bucket"。

上传图片

1. 上传一张令人反感的图片，比如这张肉食僵尸图片：

   gcloud storage cp zombie.jpg gs://YOUR_INPUT_BUCKET_NAME

   其中 YOUR_INPUT_BUCKET_NAME 是您之前为了上传图片而创建的 Cloud Storage 存储桶。

2. 您应该会在日志中看到图片分析：

   gcloud beta functions logs read YOUR_FUNCTION_NAME --gen2 --limit=100

3. 您可以在之前创建的 YOUR_OUTPUT_BUCKET_NAME Cloud Storage 存储桶中查看经过模糊处理的图片。

清理

为避免因本教程中使用的资源导致您的 Google Cloud 账号产生费用，请删除包含这些资源的项目，或者保留项目但删除各个资源。

删除项目

为了避免产生费用，最简单的方法是删除您为本教程创建的项目。

要删除项目，请执行以下操作：

注意：删除项目会产生以下影响：

• 项目中的所有内容都会被删除。如果您将现有项目用于本文档中的任务，则删除该项目后，还将删除您已在该项目中完成的任何其他工作。
• 自定义项目 ID 丢失。创建此项目时，您可能创建了要在将来使用的自定义项目 ID。要保留使用该项目 ID 的网址（例如 appspot.com 网址），请删除项目内的所选资源，而不是删除整个项目。

如果您打算探索多个架构、教程或快速入门，则重复使用项目可以帮助您避免超出项目配额限制。

1. In the Google Cloud console, go to the Manage resources page.

   Go to Manage resources

2. In the project list, select the project that you want to delete, and then click Delete.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

删除 Cloud Run functions 函数

删除 Cloud Run functions 函数不会移除存储在 Cloud Storage 中的任何资源。

如需删除您在本教程中部署的函数，请运行以下命令：

Node.js

gcloud functions delete nodejs-blur-function --gen2 --region REGION 

Python

gcloud functions delete python-blur-function --gen2 --region REGION 

Go

gcloud functions delete go-blur-function --gen2 --region REGION 

Java

gcloud functions delete java-blur-function --gen2 --region REGION 

您也可以通过 Google Cloud 控制台删除 Cloud Run functions。