.. _scanmid:

====
Scan
====

    1. CSP Leaf Node provides API for **Scan workflow**.
    2. The CSP Leaf Node **accepts the command** if :-

        A. Operational **state** of the CSP Leaf node is **ON/OFF/INIT/STANDBY/ALARM**
        B. CSP Subarray is responsive.

    3. The CSP Leaf Node **rejects the command** if :-

        A. Operational **state** of CSP Leaf node is **FAULT/UNKNOWN/DISABLE** .
        B. CSP Subarray is not responsive.

    4. The following **state requirements** are applied for the **command execution** :-

        A. CSP Subarray is in 'observation state' **READY** .
        B. CSP Subarray node is :term:`available` .

    5. The **command execution** involves below **key operations** :-

        A. The Input JSON is **validated** and **if malformed** , and **Command is 'Failed'** with exception message
        B. **Checks** are done to check if JSON contains **"interface"** and **"scan_id"** keys. **Absence** of any required key or an empty resources list leads to a **failed** Command failure with exception message.This will be reported on long running command result.
        C. The command is then invoked on the CSP Subarray.

            - If CSP Subarray **raises exception** , command failure is reported as **'RESULT_CODE - FAILED'** on Long Running Command Result attribute of the CSP leaf node.
            - If CSP Subarray **accept command** , the TMC CSP leaf node will wait for command completion.

    6. The CSP leaf node **monitors the progress** of command via the CSP sub-array node **ObsState transitions** and the **long running command results**.

        A. Command is **successful** when the CSP Subarray sends **'RESULT_CODE - OK'** on Long Running Command Result attribute of the CSP Subarray. This is reported as **'RESULT_CODE - OK'** on Long Running Command Result attribute of the TMC CSP Subarray node.
        B. Command **failure** is reported in any of the below cases as **'RESULT_CODE - FAILED'** on Long Running Command Result attribute of the TMC CSP Subarray leaf node.

            - The CSP Subarray reports **'RESULT_CODE - FAILED'** on its Long Running Command Result attribute
            - The command **times out** if CSP SubarrayNode does not receive **'RESULT_CODE - OK'** from CSP Subarray within the **timeout period** specified by `CommandTimeOutDefault` property specified in helm chart of the CSP Leaf Node .