在 JSON 中将数据从 Kafka 主题推送到 PostgreSQL

Question

更新后出错

[2019-07-29 12:52:23,301] INFO Initializing writer using SQL dialect: PostgreSqlDatabaseDialect (io.confluent.connect.jdbc.sink.JdbcSinkTask:57)
[2019-07-29 12:52:23,303] INFO WorkerSinkTask{id=sink-postgres-0} Sink task finished initialization and start (org.apache.kafka.connect.runtime.WorkerSinkTask:301)
[2019-07-29 12:52:23,367] WARN [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Error while fetching metadata with correlation id 2 : {kafkadad=LEADER_NOT_AVAILABLE} (org.apache.kafka.clients.NetworkClient:1023)
[2019-07-29 12:52:23,368] INFO Cluster ID: _gRuX5-0SUu72wzy6PV0Ag (org.apache.kafka.clients.Metadata:365)
[2019-07-29 12:52:23,369] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Discovered group coordinator INTRIVMPIOT01.xpetize.local:9092 (id: 2147483647 rack: null) (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:675)
[2019-07-29 12:52:23,372] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Revoking previously assigned partitions [] (org.apache.kafka.clients.consumer.internals.ConsumerCoordinator:459)
[2019-07-29 12:52:23,373] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] (Re-)joining group (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:491)
[2019-07-29 12:52:23,383] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] (Re-)joining group (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:491)
[2019-07-29 12:52:23,482] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Successfully joined group with generation 1 (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:455)
[2019-07-29 12:52:23,486] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Setting newly assigned partitions: kafkadad-0 (org.apache.kafka.clients.consumer.internals.ConsumerCoordinator:290)
[2019-07-29 12:52:23,501] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Resetting offset for partition kafkadad-0 to offset 0. (org.apache.kafka.clients.consumer.internals.Fetcher:584)
[2019-07-29 12:52:35,338] ERROR WorkerSinkTask{id=sink-postgres-0} Task threw an uncaught and unrecoverable exception (org.apache.kafka.connect.runtime.WorkerTask:177)
org.apache.kafka.connect.errors.ConnectException: Tolerance exceeded in error handler
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:178)
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execute(RetryWithToleranceOperator.java:104)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.convertAndTransformRecord(WorkerSinkTask.java:487)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.convertMessages(WorkerSinkTask.java:464)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.poll(WorkerSinkTask.java:320)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.iteration(WorkerSinkTask.java:224)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.execute(WorkerSinkTask.java:192)
        at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:175)
        at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:219)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
        at org.apache.kafka.connect.json.JsonConverter.convertToConnect(JsonConverter.java:701)
        at org.apache.kafka.connect.json.JsonConverter.access[=11=]0(JsonConverter.java:61)
        at org.apache.kafka.connect.json.JsonConverter.convert(JsonConverter.java:181)
        at org.apache.kafka.connect.json.JsonConverter.convertToConnect(JsonConverter.java:745)
        at org.apache.kafka.connect.json.JsonConverter.toConnectData(JsonConverter.java:363)
        at org.apache.kafka.connect.runtime.WorkerSinkTask.lambda$convertAndTransformRecord(WorkerSinkTask.java:487)
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndRetry(RetryWithToleranceOperator.java:128)
        at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:162)
        ... 13 more
[2019-07-29 12:52:35,347] ERROR WorkerSinkTask{id=sink-postgres-0} Task is being killed and will not recover until manually restarted (org.apache.kafka.connect.runtime.WorkerTask:178)
[2019-07-29 12:52:35,347] INFO Stopping task (io.confluent.connect.jdbc.sink.JdbcSinkTask:105)
[2019-07-29 12:52:35,349] INFO [Consumer clientId=consumer-1, groupId=connect-sink-postgres] Member consumer-1-bdbc7035-7625-4701-9ca7-c1ffa6863456 sending LeaveGroup request to coordinator INTRIVMPIOT01.xpetize.local:9092 (id: 2147483647 rack: null) (org.apache.kafka.clients.consumer.internals.AbstractCoordinator:822)

生产者控制台：

连接-standalone.properties文件

bootstrap.servers=localhost:9092 
key.converter=org.apache.kafka.connect.json.JsonConverter 
value.converter=org.apache.kafka.connect.json.JsonConverter 
key.converter.schemas.enable=false 
value.converter.schemas.enable=true

offset.storage.file.filename=/tmp/connect.offsets 
offset.flush.interval.ms=10000
plugin.path=/home/kafka/confluent-5.2.1/share/java

连接-post.properties文件

name=sink-postgres
connector.class=io.confluent.connect.jdbc.JdbcSinkConnector
tasks.max=2
topics=kafkada
connection.url=jdbc:postgresql://localhost:5432/kafkadb?
user=postgres&password=postgres
insert.mode=upsert
table.name.format=kafkatable
pk.mode=none
pk.fields=none
auto.create=true 
auto.evolve=false
offset.storage.file.filename=/tmp/post-sink.offsets

上面的错误是我通过apache kafka./bin/connect-standalone.sh config/connect-standalone.properties config.postgresql.properties造成的。

然后，我已经尝试并实现了这个link中提到的流程：

https://hellokoding.com/kafka-connect-sinks-data-to-postgres-example-with-avro-schema-registry-and-python

但是，这里的数据是使用 avro 从 Python 代码生成的。但就我而言，我已经在 kafka 主题中有来自传感器的数据（JSON 格式），我想将其发送到 postgreSQL，而不是通过代码生成数据。

那么，如何实现从kafka主题向postgreSQL发送数据的流程。

我已经分享了我的属性文件，如果需要更正，请告诉我。我正在发送简单的 json 数据，例如 "{"cust_id": 1313131, "month": 12, "expenses": 1313.13}" 我也尝试发送这种类型的数据，但仍然出错存在

样本json数据

 {
        "schema": {
            "type": "struct",
            "fields": [
                {
                    "type": "int32",
                    "optional": false,
                    "field": "customer_id"
                },
                {
                    "type": "int32",
                    "optional": true,
                    "field": "month"
                },

                {
                    "type": "string",
                    "optional": true,
                    "field": "amount_paid"
                }
            ],
            "optional": false,
            "name": "msgschema"
        },
        "payload": {
           "cust_id": 13, 
           "month": 12, 
           "expenses": 1313.13
        }
    }

我有一个名为 kafkatable 的 table，它的列名称为 (customer_id, month, amount_paid) 使用

创建

"CREATE TABLE kafkatable( customer_id int8, month int4, amount_paid decimal(9,2) );"

Answer 1

Kafka Connect 是 Apache Kafka 的一部分，非常适合这一点。您可以从总体上了解更多关于 Kafka Connect 的信息 here。

要将数据从 Kafka 主题流式传输到 Postgres（或任何其他数据库），请使用 JDBC 接收器连接器，您可以从 here 获得该连接器。

Answer 2

我通过进行以下更改解决了这个错误

insert.mode=插入
注释掉 table.name.format=kafkatable 因为 table 将通过自动创建创建
删除第 connection.url 行末尾的问号。
pk.fields 此处不应保留 none，请务必提供列名以避免并发症。
postgresql 不支持 int32，所以当我将其更改为 int8 时它工作正常。
您的架构和负载中的字段名称不同，请确保提供相同的名称。

在 JSON 中将数据从 Kafka 主题推送到 PostgreSQL

Push Data from Kafka Topic to PostgreSQL in JSON

postgresql

apache-kafka

apache-kafka-connect

confluent-platform