 在 TensorFlow.org 上查看
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 在 Google Colab 中运行
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 在 GitHub 上查看源代码
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 下载笔记本
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概览
本教程重点介绍如何将数据从 Kafka 集群流式传输到 tf.data.Dataset 中，然后将其与 tf.keras 结合用于训练和推理。
Kafka 主要是一个分布式事件流式传输平台，它可以在数据管道中提供可扩展且容错的流数据。它是众多大型企业的一项重要技术组件，而任务关键型数据交付是其主要要求。
设置
安装所需的 tensorflow-io 和 kafka 软件包
pip install tensorflow-iopip install kafka-python
导入软件包
import os
from datetime import datetime
import time
import threading
import json
from kafka import KafkaProducer
from kafka.errors import KafkaError
from sklearn.model_selection import train_test_split
import pandas as pd
import tensorflow as tf
import tensorflow_io as tfio
验证 tf 和 tfio 导入
print("tensorflow-io version: {}".format(tfio.__version__))
print("tensorflow version: {}".format(tf.__version__))
tensorflow-io version: 0.23.1 tensorflow version: 2.8.0-rc0
下载并设置 Kafka 和 Zookeeper 实例
出于演示目的，以下实例在本地设置
- Kafka（代理：127.0.0.1:9092）
- Zookeeper（节点：127.0.0.1:2181）
curl -sSOL https://downloads.apache.org/kafka/2.7.2/kafka_2.13-2.7.2.tgztar -xzf kafka_2.13-2.7.2.tgz
使用 Apache Kafka 提供的默认配置来启动实例。
./kafka_2.13-2.7.2/bin/zookeeper-server-start.sh -daemon ./kafka_2.13-2.7.2/config/zookeeper.properties./kafka_2.13-2.7.2/bin/kafka-server-start.sh -daemon ./kafka_2.13-2.7.2/config/server.propertiesecho "Waiting for 10 secs until kafka and zookeeper services are up and running"sleep 10
Waiting for 10 secs until kafka and zookeeper services are up and running
一旦实例作为守护进程启动，就在进程列表中 grep kafka。这两个 Java 进程对应于 zookeeper 和 kafka 实例。
ps -ef | grep kafka
kbuilder 27856 20044 4 20:28 ? 00:00:00 python /tmpfs/src/gfile/executor.py --input_notebook=/tmpfs/src/temp/docs/tutorials/kafka.ipynb --timeout=15000 kbuilder 28271 1 16 20:28 ? 00:00:01 java -Xmx512M -Xms512M -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+ExplicitGCInvokesConcurrent -XX:MaxInlineLevel=15 -Djava.awt.headless=true -Xlog:gc*:file=/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../logs/zookeeper-gc.log:time,tags:filecount=10,filesize=100M -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../logs -Dlog4j.configuration=file:./kafka_2.13-2.7.2/bin/../config/log4j.properties -cp /tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/activation-1.1.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/aopalliance-repackaged-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/argparse4j-0.7.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/audience-annotations-0.5.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/commons-cli-1.4.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/commons-lang3-3.8.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-api-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-basic-auth-extension-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-file-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-json-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-mirror-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-mirror-client-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-runtime-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-transforms-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/hk2-api-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/hk2-locator-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/hk2-utils-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-annotations-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-core-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-databind-2.10.5.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-dataformat-csv-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-datatype-jdk8-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-jaxrs-base-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-jaxrs-json-provider-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-module-jaxb-annotations-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-module-paranamer-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-module-scala_2.13-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.activation-api-1.2.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.annotation-api-1.3.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.inject-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.validation-api-2.0.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.ws.rs-api-2.1.6.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.xml.bind-api-2.3.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javassist-3.25.0-GA.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javassist-3.26.0-GA.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javax.servlet-api-3.1.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javax.ws.rs-api-2.1.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jaxb-api-2.3.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-client-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-common-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-container-servlet-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-container-servlet-core-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-hk2-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-server-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-client-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-continuation-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-http-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-io-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-security-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-server-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-servlet-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-servlets-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-util-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-util-ajax-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jopt-simple-5.0.4.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-clients-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-log4j-appender-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-raft-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-examples-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-scala_2.13-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-test-utils-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-tools-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka_2.13-2.7.2-sources.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka_2.13-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/log4j-1.2.17.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/lz4-java-1.7.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/maven-artifact-3.8.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/metrics-core-2.2.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-buffer-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-codec-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-common-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-handler-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-resolver-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-transport-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-transport-native-epoll-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-transport-native-unix-common-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/osgi-resource-locator-1.0.3.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/paranamer-2.8.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/plexus-utils-3.2.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/reflections-0.9.12.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/rocksdbjni-5.18.4.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-collection-compat_2.13-2.2.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-java8-compat_2.13-0.9.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-library-2.13.3.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-logging_2.13-3.9.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-reflect-2.13.3.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/slf4j-api-1.7.30.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/slf4j-log4j12-1.7.30.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/snappy-java-1.1.7.7.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/zookeeper-3.5.9.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/zookeeper-jute-3.5.9.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/zstd-jni-1.4.5-6.jar org.apache.zookeeper.server.quorum.QuorumPeerMain ./kafka_2.13-2.7.2/config/zookeeper.properties kbuilder 28635 1 57 20:28 ? 00:00:05 java -Xmx1G -Xms1G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+ExplicitGCInvokesConcurrent -XX:MaxInlineLevel=15 -Djava.awt.headless=true -Xlog:gc*:file=/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../logs/kafkaServer-gc.log:time,tags:filecount=10,filesize=100M -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dkafka.logs.dir=/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../logs -Dlog4j.configuration=file:./kafka_2.13-2.7.2/bin/../config/log4j.properties -cp /tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/activation-1.1.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/aopalliance-repackaged-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/argparse4j-0.7.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/audience-annotations-0.5.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/commons-cli-1.4.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/commons-lang3-3.8.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-api-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-basic-auth-extension-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-file-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-json-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-mirror-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-mirror-client-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-runtime-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/connect-transforms-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/hk2-api-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/hk2-locator-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/hk2-utils-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-annotations-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-core-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-databind-2.10.5.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-dataformat-csv-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-datatype-jdk8-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-jaxrs-base-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-jaxrs-json-provider-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-module-jaxb-annotations-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-module-paranamer-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jackson-module-scala_2.13-2.10.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.activation-api-1.2.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.annotation-api-1.3.5.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.inject-2.6.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.validation-api-2.0.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.ws.rs-api-2.1.6.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jakarta.xml.bind-api-2.3.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javassist-3.25.0-GA.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javassist-3.26.0-GA.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javax.servlet-api-3.1.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/javax.ws.rs-api-2.1.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jaxb-api-2.3.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-client-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-common-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-container-servlet-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-container-servlet-core-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-hk2-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jersey-server-2.34.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-client-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-continuation-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-http-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-io-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-security-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-server-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-servlet-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-servlets-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-util-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jetty-util-ajax-9.4.43.v20210629.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/jopt-simple-5.0.4.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-clients-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-log4j-appender-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-raft-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-examples-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-scala_2.13-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-streams-test-utils-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka-tools-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka_2.13-2.7.2-sources.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/kafka_2.13-2.7.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/log4j-1.2.17.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/lz4-java-1.7.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/maven-artifact-3.8.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/metrics-core-2.2.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-buffer-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-codec-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-common-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-handler-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-resolver-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-transport-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-transport-native-epoll-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/netty-transport-native-unix-common-4.1.59.Final.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/osgi-resource-locator-1.0.3.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/paranamer-2.8.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/plexus-utils-3.2.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/reflections-0.9.12.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/rocksdbjni-5.18.4.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-collection-compat_2.13-2.2.0.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-java8-compat_2.13-0.9.1.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-library-2.13.3.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-logging_2.13-3.9.2.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/scala-reflect-2.13.3.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/slf4j-api-1.7.30.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/slf4j-log4j12-1.7.30.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/snappy-java-1.1.7.7.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/zookeeper-3.5.9.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/zookeeper-jute-3.5.9.jar:/tmpfs/src/temp/docs/tutorials/kafka_2.13-2.7.2/bin/../libs/zstd-jni-1.4.5-6.jar kafka.Kafka ./kafka_2.13-2.7.2/config/server.properties kbuilder 28821 27860 0 20:28 pts/0 00:00:00 /bin/bash -c ps -ef | grep kafka kbuilder 28823 28821 0 20:28 pts/0 00:00:00 grep kafka
使用以下规范创建 kafka 主题
- susy-train：分区=1，复制因子=1
- susy-test：分区=2，复制因子=1
./kafka_2.13-2.7.2/bin/kafka-topics.sh --create --bootstrap-server 127.0.0.1:9092 --replication-factor 1 --partitions 1 --topic susy-train./kafka_2.13-2.7.2/bin/kafka-topics.sh --create --bootstrap-server 127.0.0.1:9092 --replication-factor 1 --partitions 2 --topic susy-test
Created topic susy-train. Created topic susy-test.
描述主题以了解配置的详细信息
./kafka_2.13-2.7.2/bin/kafka-topics.sh --describe --bootstrap-server 127.0.0.1:9092 --topic susy-train./kafka_2.13-2.7.2/bin/kafka-topics.sh --describe --bootstrap-server 127.0.0.1:9092 --topic susy-test
Topic: susy-train PartitionCount: 1 ReplicationFactor: 1 Configs: segment.bytes=1073741824
Topic: susy-train Partition: 0 Leader: 0 Replicas: 0 Isr: 0
Topic: susy-test PartitionCount: 2 ReplicationFactor: 1 Configs: segment.bytes=1073741824
Topic: susy-test Partition: 0 Leader: 0 Replicas: 0 Isr: 0
Topic: susy-test Partition: 1 Leader: 0 Replicas: 0 Isr: 0
复制因子 1 指示数据未被复制。这是由于我们的 kafka 设置中存在单个代理。在生产系统中，引导服务器的数量可以达到 100 个节点。这就是使用复制的容错性发挥作用的地方。
请参阅 文档 了解更多详情。
SUSY 数据集
Kafka 是一个事件流平台，它允许将来自各种来源的数据写入其中。例如
- 网络流量日志
- 天文测量
- 物联网传感器数据
- 产品评论等等。
为了本教程的目的，让我们下载 SUSY 数据集，并手动将数据馈送到 kafka。此分类问题的目标是区分产生超对称粒子的信号过程和不产生超对称粒子的背景过程。
curl -sSOL https://archive.ics.uci.edu/ml/machine-learning-databases/00279/SUSY.csv.gz
探索数据集
第一列是类别标签（信号为 1，背景为 0），后面是 18 个特征（8 个低级特征，然后是 10 个高级特征）。前 8 个特征是加速器中的粒子探测器测量的运动学属性。后 10 个特征是前 8 个特征的函数。这些是由物理学家推导出的高级特征，有助于区分这两个类别。
COLUMNS = [
# labels
'class',
# low-level features
'lepton_1_pT',
'lepton_1_eta',
'lepton_1_phi',
'lepton_2_pT',
'lepton_2_eta',
'lepton_2_phi',
'missing_energy_magnitude',
'missing_energy_phi',
# high-level derived features
'MET_rel',
'axial_MET',
'M_R',
'M_TR_2',
'R',
'MT2',
'S_R',
'M_Delta_R',
'dPhi_r_b',
'cos(theta_r1)'
]
整个数据集包含 500 万行。但是，为了本教程的目的，我们只考虑数据集的一部分（100,000 行），这样就可以减少移动数据所花费的时间，而将更多时间花在了解 api 的功能上。
susy_iterator = pd.read_csv('SUSY.csv.gz', header=None, names=COLUMNS, chunksize=100000)
susy_df = next(susy_iterator)
susy_df.head()
# Number of datapoints and columns
len(susy_df), len(susy_df.columns)
(100000, 19)
# Number of datapoints belonging to each class (0: background noise, 1: signal)
len(susy_df[susy_df["class"]==0]), len(susy_df[susy_df["class"]==1])
(54025, 45975)
拆分数据集
train_df, test_df = train_test_split(susy_df, test_size=0.4, shuffle=True)
print("Number of training samples: ",len(train_df))
print("Number of testing sample: ",len(test_df))
x_train_df = train_df.drop(["class"], axis=1)
y_train_df = train_df["class"]
x_test_df = test_df.drop(["class"], axis=1)
y_test_df = test_df["class"]
# The labels are set as the kafka message keys so as to store data
# in multiple-partitions. Thus, enabling efficient data retrieval
# using the consumer groups.
x_train = list(filter(None, x_train_df.to_csv(index=False).split("\n")[1:]))
y_train = list(filter(None, y_train_df.to_csv(index=False).split("\n")[1:]))
x_test = list(filter(None, x_test_df.to_csv(index=False).split("\n")[1:]))
y_test = list(filter(None, y_test_df.to_csv(index=False).split("\n")[1:]))
Number of training samples: 60000 Number of testing sample: 40000
NUM_COLUMNS = len(x_train_df.columns)
len(x_train), len(y_train), len(x_test), len(y_test)
(60000, 60000, 40000, 40000)
将训练和测试数据存储在 kafka 中
将数据存储在 kafka 中模拟了一个环境，用于持续远程检索数据以进行训练和推理。
def error_callback(exc):
raise Exception('Error while sendig data to kafka: {0}'.format(str(exc)))
def write_to_kafka(topic_name, items):
count=0
producer = KafkaProducer(bootstrap_servers=['127.0.0.1:9092'])
for message, key in items:
producer.send(topic_name, key=key.encode('utf-8'), value=message.encode('utf-8')).add_errback(error_callback)
count+=1
producer.flush()
print("Wrote {0} messages into topic: {1}".format(count, topic_name))
write_to_kafka("susy-train", zip(x_train, y_train))
write_to_kafka("susy-test", zip(x_test, y_test))
Wrote 60000 messages into topic: susy-train Wrote 40000 messages into topic: susy-test
定义 tfio 训练数据集
IODataset 类用于将数据从 kafka 流式传输到 tensorflow。该类继承自 tf.data.Dataset，因此具有 tf.data.Dataset 的所有有用功能。
def decode_kafka_item(item):
message = tf.io.decode_csv(item.message, [[0.0] for i in range(NUM_COLUMNS)])
key = tf.strings.to_number(item.key)
return (message, key)
BATCH_SIZE=64
SHUFFLE_BUFFER_SIZE=64
train_ds = tfio.IODataset.from_kafka('susy-train', partition=0, offset=0)
train_ds = train_ds.shuffle(buffer_size=SHUFFLE_BUFFER_SIZE)
train_ds = train_ds.map(decode_kafka_item)
train_ds = train_ds.batch(BATCH_SIZE)
2022-01-07 20:29:21.602817: E tensorflow/stream_executor/cuda/cuda_driver.cc:271] failed call to cuInit: CUDA_ERROR_NO_DEVICE: no CUDA-capable device is detected
构建并训练模型
# Set the parameters
OPTIMIZER="adam"
LOSS=tf.keras.losses.BinaryCrossentropy(from_logits=True)
METRICS=['accuracy']
EPOCHS=10
# design/build the model
model = tf.keras.Sequential([
tf.keras.layers.Input(shape=(NUM_COLUMNS,)),
tf.keras.layers.Dense(128, activation='relu'),
tf.keras.layers.Dropout(0.2),
tf.keras.layers.Dense(256, activation='relu'),
tf.keras.layers.Dropout(0.4),
tf.keras.layers.Dense(128, activation='relu'),
tf.keras.layers.Dropout(0.4),
tf.keras.layers.Dense(1, activation='sigmoid')
])
print(model.summary())
Model: "sequential"
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
dense (Dense) (None, 128) 2432
dropout (Dropout) (None, 128) 0
dense_1 (Dense) (None, 256) 33024
dropout_1 (Dropout) (None, 256) 0
dense_2 (Dense) (None, 128) 32896
dropout_2 (Dropout) (None, 128) 0
dense_3 (Dense) (None, 1) 129
=================================================================
Total params: 68,481
Trainable params: 68,481
Non-trainable params: 0
_________________________________________________________________
None
# compile the model
model.compile(optimizer=OPTIMIZER, loss=LOSS, metrics=METRICS)
# fit the model
model.fit(train_ds, epochs=EPOCHS)
Epoch 1/10 /tmpfs/src/tf_docs_env/lib/python3.7/site-packages/tensorflow/python/util/dispatch.py:1082: UserWarning: "`binary_crossentropy` received `from_logits=True`, but the `output` argument was produced by a sigmoid or softmax activation and thus does not represent logits. Was this intended?" return dispatch_target(*args, **kwargs) 938/938 [==============================] - 31s 33ms/step - loss: 0.4817 - accuracy: 0.7691 Epoch 2/10 938/938 [==============================] - 30s 32ms/step - loss: 0.4550 - accuracy: 0.7875 Epoch 3/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4512 - accuracy: 0.7911 Epoch 4/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4487 - accuracy: 0.7940 Epoch 5/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4466 - accuracy: 0.7934 Epoch 6/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4459 - accuracy: 0.7933 Epoch 7/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4448 - accuracy: 0.7935 Epoch 8/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4439 - accuracy: 0.7950 Epoch 9/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4421 - accuracy: 0.7956 Epoch 10/10 938/938 [==============================] - 31s 32ms/step - loss: 0.4425 - accuracy: 0.7962 <keras.callbacks.History at 0x7fb364fd2a90>
由于仅使用了数据集的一部分，因此我们的准确性在训练阶段限制在约 78%。不过，请随时将更多数据存储在 kafka 中，以获得更好的模型性能。此外，由于目标只是演示 tfio kafka 数据集的功能，因此使用了较小且不太复杂的卷积神经网络。不过，可以增加模型的复杂性，修改学习策略，调整超参数等，以进行探索。有关基准方法，请参阅此 文章。
对测试数据进行推理
要对测试数据进行推理，同时遵守“恰好一次”语义和容错性，可以使用 streaming.KafkaGroupIODataset。
定义 tfio 测试数据集
stream_timeout 参数会阻塞给定持续时间，以等待将新数据点流式传输到主题中。如果数据以间歇性方式流式传输到主题中，则无需创建新数据集。
test_ds = tfio.experimental.streaming.KafkaGroupIODataset(
topics=["susy-test"],
group_id="testcg",
servers="127.0.0.1:9092",
stream_timeout=10000,
configuration=[
"session.timeout.ms=7000",
"max.poll.interval.ms=8000",
"auto.offset.reset=earliest"
],
)
def decode_kafka_test_item(raw_message, raw_key):
message = tf.io.decode_csv(raw_message, [[0.0] for i in range(NUM_COLUMNS)])
key = tf.strings.to_number(raw_key)
return (message, key)
test_ds = test_ds.map(decode_kafka_test_item)
test_ds = test_ds.batch(BATCH_SIZE)
WARNING:tensorflow:From /tmpfs/src/tf_docs_env/lib/python3.7/site-packages/tensorflow_io/python/experimental/kafka_group_io_dataset_ops.py:188: take_while (from tensorflow.python.data.experimental.ops.take_while_ops) is deprecated and will be removed in a future version. Instructions for updating: Use `tf.data.Dataset.take_while(...)
虽然此类可用于训练目的，但需要解决一些注意事项。一旦从 kafka 中读取所有消息并使用 streaming.KafkaGroupIODataset 提交最新偏移量，使用者就不会从头开始重新读取消息。因此，在训练时，只能使用连续流入的数据训练单个 epoch。此类功能在训练阶段的用例有限，其中一旦模型使用数据点，就不再需要该数据点，可以将其丢弃。
不过，当涉及到具有“恰好一次”语义的稳健推理时，此功能就非常出色。
评估测试数据的性能
res = model.evaluate(test_ds)
print("test loss, test acc:", res)
34/Unknown - 0s 2ms/step - loss: 0.4434 - accuracy: 0.8194 2022-01-07 20:34:29.402707: E tensorflow_io/core/kernels/kafka_kernels.cc:774] REBALANCE: Local: Assign partitions 2022-01-07 20:34:29.406789: E tensorflow_io/core/kernels/kafka_kernels.cc:776] Retrieved committed offsets with status code: 0 625/625 [==============================] - 11s 17ms/step - loss: 0.4437 - accuracy: 0.7915 test loss, test acc: [0.4436523914337158, 0.7915250062942505] 2022-01-07 20:34:40.051954: E tensorflow_io/core/kernels/kafka_kernels.cc:1001] Local: Timed out
由于推理基于“恰好一次”语义，因此只能对测试集进行一次评估。要再次对测试数据运行推理，应使用新的使用者组。
跟踪 testcg 使用者组的偏移量滞后
./kafka_2.13-2.7.2/bin/kafka-consumer-groups.sh --bootstrap-server 127.0.0.1:9092 --describe --group testcg
GROUP TOPIC PARTITION CURRENT-OFFSET LOG-END-OFFSET LAG CONSUMER-ID HOST CLIENT-ID testcg susy-test 0 21626 21626 0 rdkafka-534f63d0-b91e-4976-a3ca-832b6c91210e /10.142.0.103 rdkafka testcg susy-test 1 18374 18374 0 rdkafka-534f63d0-b91e-4976-a3ca-832b6c91210e /10.142.0.103 rdkafka
一旦 current-offset 与所有分区的 log-end-offset 匹配，就表示使用者已完成从 kafka 主题中获取所有消息。
在线学习
在线机器学习范例与训练机器学习模型的传统/常规方式略有不同。在前一种情况下，模型会继续逐步学习/更新其参数，只要有新的数据点可用，并且此过程预计会无限期地持续下去。这与后一种方法不同，后一种方法的数据集是固定的，并且模型会对其进行 n 次迭代。在在线学习中，一旦模型使用数据，这些数据可能无法再次用于训练。
通过使用 streaming.KafkaBatchIODataset，现在可以按此方式训练模型。让我们继续使用我们的 SUSY 数据集来演示此功能。
用于在线学习的 tfio 训练数据集
在 API 中，streaming.KafkaBatchIODataset 类似于 streaming.KafkaGroupIODataset。此外，建议使用 stream_timeout 参数来配置数据集在超时之前阻塞新消息的持续时间。在以下实例中，数据集配置了 stream_timeout，值为 10000 毫秒。这意味着，在主题中的所有消息都被使用后，数据集将在超时并断开与 Kafka 集群的连接之前再等待 10 秒。如果在超时之前将新消息流式传输到主题中，则会恢复对新使用的数据点的数据使用和模型训练。若要无限期地阻塞，请将其设置为 -1。
online_train_ds = tfio.experimental.streaming.KafkaBatchIODataset(
topics=["susy-train"],
group_id="cgonline",
servers="127.0.0.1:9092",
stream_timeout=10000, # in milliseconds, to block indefinitely, set it to -1.
configuration=[
"session.timeout.ms=7000",
"max.poll.interval.ms=8000",
"auto.offset.reset=earliest"
],
)
由 online_train_ds 生成的每个项目本身都是 tf.data.Dataset。因此，所有标准转换都可以照常应用。
def decode_kafka_online_item(raw_message, raw_key):
message = tf.io.decode_csv(raw_message, [[0.0] for i in range(NUM_COLUMNS)])
key = tf.strings.to_number(raw_key)
return (message, key)
for mini_ds in online_train_ds:
mini_ds = mini_ds.shuffle(buffer_size=32)
mini_ds = mini_ds.map(decode_kafka_online_item)
mini_ds = mini_ds.batch(32)
if len(mini_ds) > 0:
model.fit(mini_ds, epochs=3)
2022-01-07 20:34:42.024915: E tensorflow_io/core/kernels/kafka_kernels.cc:774] REBALANCE: Local: Assign partitions 2022-01-07 20:34:42.025797: E tensorflow_io/core/kernels/kafka_kernels.cc:776] Retrieved committed offsets with status code: 0 Epoch 1/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4561 - accuracy: 0.7909 Epoch 2/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4538 - accuracy: 0.7909 Epoch 3/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4499 - accuracy: 0.7947 Epoch 1/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4347 - accuracy: 0.8018 Epoch 2/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4314 - accuracy: 0.8048 Epoch 3/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4286 - accuracy: 0.8063 Epoch 1/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4480 - accuracy: 0.7910 Epoch 2/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4425 - accuracy: 0.7945 Epoch 3/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4390 - accuracy: 0.7970 Epoch 1/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4434 - accuracy: 0.7965 Epoch 2/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4380 - accuracy: 0.7974 Epoch 3/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4354 - accuracy: 0.7992 Epoch 1/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4522 - accuracy: 0.7909 Epoch 2/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4475 - accuracy: 0.7910 Epoch 3/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4435 - accuracy: 0.7947 Epoch 1/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4464 - accuracy: 0.7906 Epoch 2/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4467 - accuracy: 0.7922 Epoch 3/3 313/313 [==============================] - 1s 2ms/step - loss: 0.4424 - accuracy: 0.7933 2022-01-07 20:35:04.916208: E tensorflow_io/core/kernels/kafka_kernels.cc:1001] Local: Timed out
可以定期（根据用例）保存增量训练的模型，并可用于在线或离线模式下对测试数据进行推断。
参考
Baldi, P.、P. Sadowski 和 D. Whiteson。“利用深度学习在高能物理中搜索奇异粒子”。自然通讯 5（2014 年 7 月 2 日）