Flink Connector for Apache Doris

Flink Doris Connector

Flink Doris Connector supports the following Flink versions:

Flink 2.x artifacts are compiled with Java 17 (--release 17, classfile major version 61) and can be built with JDK 17 or JDK 21. JDK 21 runtime compatibility is experimental for the Flink versions listed above; JDK 17 remains the recommended runtime.

If you wish to contribute or use a connector from flink 1.13 (and earlier), please use the branch-for-flink-before-1.13

More information about compilation and usage is available in the Flink Doris Connector documentation. The website documentation is maintained outside this repository and requires a separate change to keep its compatibility guidance in sync.

TLS Configuration

The connector can apply one TLS policy to Doris HTTP, MySQL/JDBC, BE Thrift, and Arrow Flight SQL connections:

doris.enable.tls=true
doris.tls.ca-certificate-path=/etc/doris-tls/ca-chain.pem
doris.tls.skip-hostname-verification=false
doris.tls.excluded-protocols=

doris.enable.tls is disabled by default. When TLS is enabled and the CA path is empty, the connector uses the JVM or protocol driver's default trust store. When a CA path is configured, it must point to a PEM CA certificate chain on the local filesystem of every process that connects to Doris. Hostname verification remains enabled by default.

doris.tls.excluded-protocols accepts a comma-separated subset of http, mysql, thrift, and arrowflight. Use it only when the corresponding Doris server protocol is excluded from TLS. For example, add thrift when the BE Thrift service used by the non-Flight source remains plaintext. The connector does not probe protocols or fall back to plaintext after a TLS failure. When Connector-managed MySQL TLS is active, do not also put TLS properties such as sslMode, useSSL, or trust-store properties in jdbc-url. Arrow Flight TLS does not support the connector's hostname-only skip policy, so doris.tls.skip-hostname-verification=true fails fast unless arrowflight is excluded.

This release supports one-way TLS only: the connector verifies the Doris server certificate but does not provide a client certificate or private key. It therefore cannot connect to a Doris endpoint configured to require client certificates.

The CA path is a local file path, not an HDFS or HTTP URI. For standalone deployments, provision the file at the same path on all relevant JobManager, TaskManager, and SQL Gateway hosts. For YARN, localize the file with yarn.ship-files and configure its container-local relative path. For Kubernetes, mount a ConfigMap or Secret into the relevant pods at a consistent absolute path. A process that opens Catalog/JDBC connections must also be able to read the file.

License

Apache License, Version 2.0

How to Build

You need to copy customer_env.sh.tpl to customer_env.sh before build and you need to configure it before build.

Build JDK requirement: Use JDK 8 for Flink 1.x. Use JDK 17 or JDK 21 for Flink 2.x; the resulting Flink 2.x artifacts still target Java 17.

git clone git@github.com:apache/doris-flink-connector.git
cd doris-flink-connector/flink-doris-connector
./build.sh

Code Style

Code Formatting

You need to install the google-java-format plugin. Spotless together with google-java-format is used to format the codes.

It is recommended to automatically format your code by applying the following settings:

1. Go to “Settings” → “Other Settings” → “google-java-format Settings”.
2. Tick the checkbox to enable the plugin.
3. Change the code style to “Android Open Source Project (AOSP) style”.
4. Go to “Settings” → “Tools” → “Actions on Save”.
5. Under “Formatting Actions”, select “Optimize imports” and “Reformat file”.
6. From the “All file types list” next to “Reformat code”, select “Java”.

For earlier IntelliJ IDEA versions, the step 4 to 7 will be changed as follows.

• 4.Go to “Settings” → “Other Settings” → “Save Actions”.
• 5.Under “General”, enable your preferred settings for when to format the code, e.g. “Activate save actions on save”.
• 6.Under “Formatting Actions”, select “Optimize imports” and “Reformat file”.
• 7.Under “File Path Inclusions”, add an entry for .*\.java to avoid formatting other file types. Then the whole project could be formatted by command mvn spotless:apply.

Checkstyle

Checkstyle is used to enforce static coding guidelines.

1. Go to “Settings” → “Tools” → “Checkstyle”.
2. Set “Scan Scope” to “Only Java sources (including tests)”.
3. For “Checkstyle Version” select “8.14”.
4. Under “Configuration File” click the “+” icon to add a new configuration.
5. Set “Description” to “doris-flink-connector”.
6. Select “Use a local Checkstyle file” and link it to the file tools/maven/checkstyle.xml which is located within your cloned repository.
7. Select “Store relative to project location” and click “Next”.
8. Configure the property checkstyle.suppressions.file with the value suppressions.xml and click “Next”.
9. Click “Finish”.
10. Select “doris-flink-connector” as the only active configuration file and click “Apply”.

You can now import the Checkstyle configuration for the Java code formatter.

1. Go to “Settings” → “Editor” → “Code Style” → “Java”.
2. Click the gear icon next to “Scheme” and select “Import Scheme” → “Checkstyle Configuration”.
3. Navigate to and select tools/maven/checkstyle.xml located within your cloned repository.

Then you could click “View” → “Tool Windows” → “Checkstyle” and find the “Check Module” button in the opened tool window to validate checkstyle. Or you can use the command mvn clean compile checkstyle:checkstyle to validate.

Report issues or submit pull request

If you find any bugs, feel free to file a GitHub issue or fix it by submitting a pull request.

Contact Us

Contact us through the following mailing list.

Links

• Doris official site - https://doris.apache.org
• Developer Mailing list - dev@doris.apache.org. Mail to dev-subscribe@doris.apache.org, follow the reply to subscribe the mail list.
• Slack channel - Join the Slack