grafana/public/app/plugins/datasource/elasticsearch/configuration/LogsConfig.tsx

import React from 'react';
import { Input, InlineField, FieldSet } from '@grafana/ui';
import { ElasticsearchOptions } from '../types';

type Props = {
  value: ElasticsearchOptions;
  onChange: (value: ElasticsearchOptions) => void;
};
export const LogsConfig = (props: Props) => {
  const { value, onChange } = props;
  const changeHandler =
    (key: keyof ElasticsearchOptions) => (event: React.SyntheticEvent<HTMLInputElement | HTMLSelectElement>) => {
      onChange({
        ...value,
        [key]: event.currentTarget.value,
      });
    };

  return (
    <FieldSet label="Logs">
      <InlineField label="Message field name" labelWidth={22}>
        <Input
          id="es_logs-config_logMessageField"
          value={value.logMessageField}
          onChange={changeHandler('logMessageField')}
          placeholder="_source"
          width={24}
        />
      </InlineField>

      <InlineField label="Level field name" labelWidth={22}>
        <Input
          id="es_logs-config_logLevelField"
          value={value.logLevelField}
          onChange={changeHandler('logLevelField')}
          width={24}
        />
      </InlineField>
    </FieldSet>
  );
};