从 Spark 读取 Pub/Sub 精简版(流式传输)
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在流式传输模式下从 Spark 集群读取来自 Pub/Sub 精简版订阅的消息。
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如需查看包含此代码示例的详细文档,请参阅以下内容:
代码示例
Python
如需向 Pub/Sub Lite 进行身份验证,请设置应用默认凭据。
如需了解详情,请参阅为本地开发环境设置身份验证。
如未另行说明,那么本页面中的内容已根据知识共享署名 4.0 许可获得了许可,并且代码示例已根据 Apache 2.0 许可获得了许可。有关详情,请参阅 Google 开发者网站政策。Java 是 Oracle 和/或其关联公司的注册商标。
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],[],[],[],null,["# Read from Pub/Sub Lite from Spark (streaming)\n\nRead messages from a Pub/Sub Lite subscription from a Spark cluster in the streaming mode.\n\nExplore further\n---------------\n\n\nFor detailed documentation that includes this code sample, see the following:\n\n- [Write Pub/Sub Lite messages by using Apache Spark](/pubsub/lite/docs/write-messages-apache-spark)\n\nCode sample\n-----------\n\n### Python\n\n\nTo authenticate to Pub/Sub Lite, set up Application Default Credentials.\nFor more information, see\n\n[Set up authentication for a local development environment](/docs/authentication/set-up-adc-local-dev-environment).\n\n from pyspark.sql import SparkSession\n from pyspark.sql.types import StringType\n\n # TODO(developer):\n # project_number = 11223344556677\n # location = \"us-central1-a\"\n # subscription_id = \"your-subscription-id\"\n\n spark = SparkSession.builder.appName(\"read-app\").master(\"yarn\").getOrCreate()\n\n sdf = (\n spark.readStream.format(\"pubsublite\")\n .option(\n \"pubsublite.subscription\",\n f\"projects/{project_number}/locations/{location}/subscriptions/{subscription_id}\",\n )\n .load()\n )\n\n sdf = sdf.withColumn(\"data\", sdf.data.cast(StringType()))\n\n query = (\n sdf.writeStream.format(\"console\")\n .outputMode(\"append\")\n .trigger(processingTime=\"1 second\")\n .start()\n )\n\n # Wait 120 seconds (must be \u003e= 60 seconds) to start receiving messages.\n query.awaitTermination(120)\n query.stop()\n\nWhat's next\n-----------\n\n\nTo search and filter code samples for other Google Cloud products, see the\n[Google Cloud sample browser](/docs/samples?product=pubsublite)."]]