Important

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Message Browser

From the Messages page, you can view the data being produced to a topic. Browse message data, seek to a specific offset or timestamp by partition, and select messages you want to download.

Prerequisites

There must be data being produced to or already present in a topic. If you don’t already have data flowing through a topic, you can use the appropriate quick start guides to get started. You can replay old data that was already produced as long as it hasn’t been compacted or deleted yet.

Inspect a topic

The Topic Inspection feature in Control Center is enabled by default. With this feature, you can inspect topic details and browse live streaming messages.

To browse a live stream of messages and inspect a topic:

1. Select a cluster from the navigation bar and click the Topics menu. The All Topics page appears.

2. In the Topics table, click the topic name link.

3. Click the Messages tab.

4. To browse the messages pane:

   • Click the horizontal (tabular view) and vertical scrollbars to view all of the available data. The newest data is displayed at the top of the messages pane. As you scroll vertically, or hover in the messages pane, a timeline arrow indicates when the messages were received.
   

   Browse topic messages in default tabular view

   • To pause scrolling incoming messages so that you can analyze the data, click the pause icon. Messages may still be produced to the topic; however, the message browser does not display newly consumed data while the view is paused. Click the play icon to resume displaying incoming messages. Clicking the cards view expand icon automatically pauses the display of incoming messages.

     

     Note

     Hovering over the messages pane also holds your place for a quick glance at data. Moving the cursor focus outside of the messages pane resumes the incoming flow of messages.

   • To filter the results, enter the criteria in the Filter by keyword box.

     

     Prefix search for topic messages by keyword of value

     Note

     Only prefix searching is currently supported. You can search for the beginning portion of a keyword. The search keyword must be the first substring in a column item. The filter matches the search string across any of the columns.

     Important

     When you are searching the audit log for user activity in the message browser, you must use the format User:<username>. To navigate to the audit log, click Cluster > Topics > confluent-audit-log-events > Messages tab.

     

     Search audit log messages by user

   • Click Query in ksqlDB to register the topic as a stream or table.

     

     Register a stream or table for a topic

   • Click Columns to select which columns you want to toggle on or off in the topic messages table. There must be populated message data for the Columns selector to appear. Narrow the view to focus on the columns of interest without resorting to horizontal scrolling. If you jump to an offset or timestamp, the table resets to show all columns again. The Columns selector is not available in the Cards view; it is only applicable to the Table view.

     

     Column selector topic messages view

   • Click the cards or table (default) icon for the layout view you prefer:

     
     

     Browse topic messages in cards view

   • Click the expand icon in the cards view to access the contents of the message. Click the Value, Header, or Key tab. Expanding the card view for a message automatically pauses the display of incoming data. Clicking the play icon collapses the expanded cards views and resumes displaying the incoming data.

     

     Expanded topic message card

Jump to an offset

To jump to a message offset, click the Jump to offset menu and enter the offset and partition. Messages are displayed in the message browser pane starting from the desired offset, and continue to feed in at the top of the message browser pane.

The record at the offset is highlighted and preselected for download.

Jump to an offset in Control Center topic message browser

Jump to a date and time

Seeking to a specified time jumps to the earliest offset where the timestamp was first recorded. Even if there are multiple data points associated with a timestamp, the seek goes to the earliest offset. Messages are displayed in the message browser pane starting from the desired time, and continue to feed in at the top of the message browser pane. Manually select any messages you want to download.

To jump to a specific date and time:

1. Click the Jump to time menu.

   

2. Click the default current date and time box to open a calendar.

   

3. Select a partition.

   Tip

   You must select a partition before trying to adjust the time or apply the new date and time.

   

4. Click a calendar date. Use the arrows to go forward or back and select a month and day.

5. Click the time box to adjust the time in hours, minutes, seconds, and AM or PM.

   

6. Click Apply.

Jump to a timestamp

To jump to a message timestamp, click the Jump to timestamp menu and enter the timestamp and partition.

The timestamp is displayed in microseconds. Enter your time of interest in milliseconds into the timestamp box and selected partition.

Tip

Use a timestamp converter to convert the timestamp into a human-readable date and time.

Seeking to a specified time jumps to the earliest offset where the timestamp was first recorded. Even if there are multiple data points associated with a timestamp, the seek goes to the earliest offset. Messages are displayed in the message browser pane starting from the desired time, and continue to feed in at the top of the message browser pane. Manually select any messages you want to download.

Jump to a timestamp in Control Center topic message browser

Download selected topic messages

Download selected rows of messages in a JSON format. When you jump to an offset, date/time, or timestamp, the record at the offset is highlighted and preselected for download. You can download messages from the Messages browser in Topics or ksqlDB.

1. Select one or more contiguous or non-contiguous rows. The download button becomes available and shows the number of selected messages.

   Tip

   Press the command key + click to select non-contiguous rows. Press shift + click on a beginning and ending row to select a contiguous range of messages.

   

   Contiguous rows selected for download

   

   Non-contiguous rows selected for download

2. Click the download icon. A file named selected_data_n.json that contains the selected messages in JSON format is downloaded into your downloads directory. The n represents the number of selected messages.

   Example filename: selected_data_3.json

   Example contents:

   [{"topic":"pageviews","partition":0,"offset":238156,"timestamp":1561686540691,"timestampType":"CREATE_TIME","headers":[],"key":"2364041","value":{"viewtime":2364041,"userid":"User_3","pageid":"Page_25"}},{"topic":"pageviews","partition":0,"offset":238155,"timestamp":1561686540662,"timestampType":"CREATE_TIME","headers":[],"key":"2364031","value":{"viewtime":2364031,"userid":"User_1","pageid":"Page_12"}},{"topic":"pageviews","partition":0,"offset":238154,"timestamp":1561686540593,"timestampType":"CREATE_TIME","headers":[],"key":"2364021","value":{"viewtime":2364021,"userid":"User_4","pageid":"Page_21"}}]
   

Enable and disable topic inspection (message browsing) in Control Center

The topic inspection feature is enabled by default in Control Center. The feature can be disabled if an organization does not want any users to access the feature. After disabling the feature, the Inspect menu and the Inspect tab are no longer visible in the Control Center UI.

To disable the inspect topic feature in Control Center:

1. Set the confluent.controlcenter.topic.inspection.enable option in your control-center.properties file to false.

   ...
   confluent.controlcenter.topic.inspection.enable=false
   ...
   

   Note

   Make the change in the appropriate Control Center properties file or files configured for your environments, including control-center-dev.properties or control-center-production.properties. The properties files are located in /path-to-confluent/etc/confluent-control-center/. For more informatin, see Control Center properties files.

2. Restart Control Center and pass in the properties file for the configuration to take effect:

   ./bin/control-center-stop
   ./bin/control-center-start ../etc/confluent-control-center/control-center.properties
   

   Tip

   If you are using a Confluent Platform development environment with a Confluent CLI, stop and start as follows:

   ./confluent local stop control-center
   ./confluent local start control-center ../etc/confluent-control-center/control-center-dev.properties
   

To enable the feature again, set the option back to true and restart Control Center with the updated properties file.

For more information about restarting Control Center and passing in its properties files, see Control Center properties files.