MongoDB Kafka Sink Connector连接失败问题求助

环境配置详情 #

1. Connect全局配置文件（connect-standalone-demo.properties） #

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# See the License for the specific language governing permissions and
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# These are defaults. This file just demonstrates how to override some settings.
bootstrap.servers=localhost:9092

# The converters specify the format of data in Kafka and how to translate it into Connect data. Every Connect user will
# need to configure these based on the format they want their data in when loaded from or stored into Kafka
key.converter=org.apache.kafka.connect.storage.StringConverter
value.converter=org.apache.kafka.connect.storage.StringConverter
#value.converter=org.apache.kafka.connect.json.JsonConverter
#key.converter=org.apache.kafka.connect.json.JsonConverter
# Converter-specific settings can be passed in by prefixing the Converter's setting with the converter we want to apply
# it to
key.converter.schemas.enable=true
value.converter.schemas.enable=true

offset.storage.file.filename=/tmp/connect.offsets
# Flush much faster than normal, which is useful for testing/debugging
offset.flush.interval.ms=10000

# Set to a list of filesystem paths separated by commas (,) to enable class loading isolation for plugins
# (connectors, converters, transformations). The list should consist of top level directories that include 
# any combination of: 
# a) directories immediately containing jars with plugins and their dependencies
# b) uber-jars with plugins and their dependencies
# c) directories immediately containing the package directory structure of classes of plugins and their dependencies
# Note: symlinks will be followed to discover dependencies or plugins.
# Examples: 
# plugin.path=/usr/local/share/java,/usr/local/share/kafka/plugins,/opt/connectors,
# plugin.path=/home/adminacl/Kafka/kafka_2.13-3.1.0/libs

2. Sink Connector配置文件（file-sink-standalone.properties） #

当前配置文件格式错误，混入了REST API请求内容：

curl -X POST -H "Content-Type: application/json" -d ' {
      "connector.class":"com.mongodb.kafka.connect.MongoSinkConnector",
      "tasks.max":"1",
      "topics":"departments",
      "connection.uri":"mongodb://localhost:27017",
      "database":"hrmdb",
      "collection":"departments",
      "key.converter":"org.apache.kafka.connect.json.JsonConverter",
      "key.converter.schemas.enable":false,
      "value.converter":"org.apache.kafka.connect.json.JsonConverter",
      "value.converter.schemas.enable":false
    
}

3. 启动命令 #

bin/connect-standalone.sh config/connect-standalone-demo.properties config/file-sink-standalone.properties 

错误信息 #

ERROR Failed to create job for config/file-sink-standalone.properties (org.apache.kafka.connect.cli.ConnectStandalone:107)
[2022-07-27 17:04:20,424] ERROR Stopping after connector error (org.apache.kafka.connect.cli.ConnectStandalone:117)

问题排查与修复 #

1. 修正Sink配置文件格式
   Standalone模式下，Connector配置文件必须使用properties格式，而非REST API的JSON格式。将file-sink-standalone.properties修改为：

connector.class=com.mongodb.kafka.connect.MongoSinkConnector
tasks.max=1
topics=departments
connection.uri=mongodb://localhost:27017
database=hrmdb
collection=departments
key.converter=org.apache.kafka.connect.json.JsonConverter
key.converter.schemas.enable=false
value.converter=org.apache.kafka.connect.json.JsonConverter
value.converter.schemas.enable=false

2. 启用Plugin路径配置
   全局配置文件中plugin.path被注释，需取消注释并指向存放MongoDB Connector jar包的目录。若jar包在Kafka的libs目录，配置如下：

plugin.path=/home/adminacl/Kafka/kafka_2.13-3.1.0/libs

建议生产环境单独创建plugins目录存放连接器jar包，避免与Kafka核心依赖冲突。

3. 统一Converter配置（可选）
   全局配置使用StringConverter且启用Schema，而Sink配置覆盖为JsonConverter并禁用Schema。需确保Kafka主题中的消息格式与Converter匹配：

• 若主题消息为无Schema的JSON，当前Sink配置有效；
• 若为带Schema的JSON，需将schemas.enable设为true。

4. 查看详细日志定位深层问题
   当前错误信息过于简略，需查看Kafka Connect的详细日志（默认路径logs/connect.log），日志中会包含具体异常栈信息（如类找不到、参数非法等），帮助精准定位问题。

内容的提问来源于stack exchange，提问作者Sherlin Susanna