Displaying Output

By default, Inspektor Gadget allows you to display the output of each data source in all the output modes supported by the CLI operator. Unless you have specific requirements, we recommend using the CLI operator's default configuration. However, for Map Iterators with a map value type of gadget_histogram_slot__u32 or gadget_histogram_slot__u64 (TODO: Add links), the output should be displayed as a chart, which the CLI operator doesn't support. In such cases, you can use the Otel Metrics operator to render the output as a histogram by annotating the data source with metrics.print: "true". The profile_blockio gadget is an example of this.

Fields

The fields to be displayed in the output when using the columns, json, jsonpretty or yaml output modes depend on the data source type:

• Tracers: The fields are all the elements of the event struct specified when defining the data source.
• Map Iterators: The fields are all the elements of the key and value structs used to define the eBPF map to be iterated. As mentioned above, there is a special case for the map iterators with a map value type of gadget_histogram_slot__u32 or gadget_histogram_slot__u64. In such cases, the data source created by the Otel Metrics operator will contain just one field called text which will carry the rendered histogram as a plain text.
• Snapshotters: The fields are all the elements of the snapshot entry struct specified when defining the data source.