Scripting

Custom-logic scripts use hooks and helpers to trigger actions, supported by available integrations, based on programmatic decisions and/or a schedule.

Kubeshark’s scripting language is based on JavaScript ES5.

The following script example calculates the number of packets and overall traffic processed per minute using an L4 network hook (onPacketCaptured), some helpers, and a job.

var packetCount = 0;
var totalKB = 0;

function onPacketCaptured(info) {
  packetCount++;
  totalKB += info.length / 1000;
}

function logPacketCountTotalBytes() {
  console.log("Captured packet count per minute:", packetCount);
  packetCount = 0;
  console.log("Total KB captured per minute:", totalKB);
  totalKB = 0;
}

jobs.schedule("log-packet-count-total-bytes", "0 */1 * * * *", logPacketCountTotalBytes);

Scripts Storage

Scripts are stored in kubeshark-config-map. You can develop and manage scripts locally in a folder and use the kubeshark scripts command to synchronize files to the config map and watch for any changes in the scripts.

Scripts code should be compliant with JavaScript ES5 and each file should have a `.js“ suffix

Example:

 kubeshark scripts --set scripting.source=/path/to/your/local/folder

Viewing and Editing Scripts in the Dashboard

While the scripts are stored in kubeshark-config-map, they can be viewed and edited in the Dashboard by accessing the Scripting section:

Script Examples Dropdown

Kubeshark comes with numerous script examples for various use cases as part of its dashboard. Use the Examples dropdown list to access the list of script examples.

Environment Variables

You can use the env configuration directive to provide environment variables for your scripts.

scripting:
  env:
    SLACK_AUTH_TOKEN: "xo.."
    SLACK_CHANNEL_ID: "C0.."
    WEBHOOK_URL: "https://webh.."
    INFLUXDB_URL: "https://us-e.."
    INFLUXDB_TOKEN: "_9r.."
    INFLUXDB_MEASUREMENT: "st.."
    INFLUXDB_ORGANIZATION: "a.."
    INFLUXDB_BUCKET: "al.."

To use any of the environment variables in a script, use the prefix: env.*. For example:

vendor.influxdb(
  env.INFLUXDB_URL,
  env.INFLUXDB_TOKEN,
  env.INFLUXDB_ORGANIZATION,
  env.INFLUXDB_BUCKET,
  "Example Measurement",        // Measurement
  data,                         // Payload
  {"example":"tag"}
);

Scopes

Kubeshark scripts support the following scopes:

• Function: When variables and functions are declared within a function.
• Script: When variables and functions are declared outside functions, at the script level, and can maintain a state across the specific script’s functions.
• Global: When using the object this, scripts and functions are declared at the global level, accessible by all scripts.