Firebase Cloud Functions部署失败问题排查与解决

我在使用Firebase Cloud Functions时，创建了一个每2小时运行的fetchNewsScheduled定时函数，该函数执行以下操作：

• 调用clearNewsCollection函数清空news集合以释放数据库空间
• 从第三方API拉取新闻数据并写入Firebase数据库

但部署时出现错误：更新us-central1区域的fetchNewsScheduled函数失败。

相关代码如下：

type ArticleType = {
  _type: string;
  name: string;
  url: string;
  image: {
    _type: string;
    thumbnail: {
      _type: string;
      contentUrl: string;
      width: number;
      height: number;
    };
    isLicensed: boolean;
  };
  description: string;
  datePublished: string;
};

type SimplifiedArticleType = {
  name: string;
  url: string;
  imageUrl: string;
  description: string;
  datePublished: string;
};

async function clearNewsCollection() {
  const snapshot = await db.collection("news").get();
  const batch = db.batch();
  snapshot.forEach((doc) => {
    batch.delete(doc.ref);
  });
  await batch.commit();
  console.log(`Deleted ${snapshot.size} documents from`);
}

async function fetchNews() {
  const options = {
    method: "GET",
    url: "https://bing-news-search1.p.rapidapi.com/news",
    params: { safeSearch: "Off", textFormat: "Raw" },
    headers: {
      "X-BingApis-SDK": "true",
      "X-RapidAPI-Key": "my_key",
      "X-RapidAPI-Host": "bing-news-search1.p.rapidapi.com",
    },
  };

  try {
    await clearNewsCollection();

    const response = await axios.request(options);

    const newsArticles = response.data.value; //an array
    const simplifiedArticles = newsArticles.map((article: ArticleType) => {
      return {
        name: article.name,
        url: article.url,
        imageUrl: article.image?.thumbnail?.contentUrl,
        description: article.description,
        datePublished: article.datePublished, //eg. "2023-03-10T14:31:02.0000000Z", moment(datePublished).fromNow();
      };
    });

    const batch = db.batch();

    simplifiedArticles.forEach((article: SimplifiedArticleType) => {
      const docRef = db.collection("news").doc();
      batch.set(docRef, article);
    });
    await batch.commit();

    console.log("Batch write successful");
  } catch (error) {
    console.log("Error writing documents:", error);
  }
}

// Define the Cloud Function to run every 2 hours
export const fetchNewsScheduled = functions.pubsub
  .schedule("every 2 hours")
  .onRun(async (context) => {
    await fetchNews();
    return null;
  });

解决方案 #

排查后发现两处疏忽性错误：

1. axios安装路径错误：需进入my-app/functions目录执行npm install axios，而非项目根目录，否则函数运行时会找不到axios依赖
2. Firebase数据库不允许存储undefined值：API返回的部分字段可能为null或undefined，直接写入会导致批量提交失败

给后续开发者的提示 #

• 检查functions目录下的package.json，确认依赖是否正确安装并添加到依赖列表中
• 绝对不能在Firebase数据库中存储undefined值，需提前为可能为空的字段设置默认值（如空字符串）

修改后的关键代码片段：

const simplifiedArticles = newsArticles.map((article: ArticleType) => {
      return {
        name: article.name || "",
        url: article.url || "",
        imageUrl: article.image?.thumbnail?.contentUrl || "",
        description: article.description || "",
        datePublished: article.datePublished || "", //eg. "2023-03-10T14:31:02.0000000Z", moment(datePublished).fromNow();
      };
    });

内容的提问来源于stack exchange，提问作者Tom Fan