Filter and pretty-print labels of Kubernetes Pods and Nodes for better reading and debugging

filter.py

#!/opt/homebrew/bin/python3
''' Help: Ensure filter.py is executable -> 'chmod u+x filter.py'
    Help: Ensure path to python executable is correct on first line -> 'which python3'
    Help: filter.py -h '''

import re, sys, argparse

class KObject:
    '''Kubernetes node or pod object'''

    def __init__(self, line, object_type):
        self.name = parse(line)['Name']
        self.labels = parse(line)['Labels']
        self.output = f" \n{object_type}: {self.name}\n\n"

    def __str__(self):
        for label in self.labels:
            self.output += f'{label}\n'
        self.output += '\n---'

        return self.output


class Colors:
    '''Color output in terminal. Extra colors for future use'''
    HEADER = '\033[95m'
    OKBLUE = '\033[94m'
    OKCYAN = '\033[96m'
    OKGREEN = '\033[92m'
    WARNING = '\033[93m'
    FAIL = '\033[91m'
    ENDC = '\033[0m'
    BOLD = '\033[1m'
    UNDERLINE = '\033[4m'


def parse(line):
    '''Parses stdin with regex and returns data of type dictionary'''

    # regex = '([a-zA-Z0-9\-\.\=\/]+,.+)'
    regex = '([a-zA-Z0-9\-\.\/]+\=[a-zA-Z0-9\-\.\/]+,.+)'
    id_regex = '^[^ ]*' # "Everything up until the first space"
    labels = []

    # Find object ID
    object_id = re.findall(id_regex, line)[0]

    # Split found labels chunk by ',' and add to list
    for label in re.findall(regex, line)[0].split(','):
        try:
            if args.val in label:
                labels.append(f'{Colors.FAIL}{label}{Colors.ENDC}')
            else:
                labels.append(label)
        except:
            labels.append(label)

    return {'Name':object_id, 'Labels':labels}





if __name__ == "__main__":

    parser = argparse.ArgumentParser(description='Pretty print & filter node and pod labels. Usage: kubectl get [nodes|pods] --show-labels | ./filter.py -v <value>')
    parser.add_argument('-v', '--val', help='Specify a value [string] to filter by')
    args = parser.parse_args()

    # Read in stdin
    stdin = sys.stdin

    # First line saved to identify k8s object type, later
    stdin_first_line = stdin.readline()

    # Continue to lines 2+
    # next(stdin)

    # Prevent errors if argument not specified
    try: args.val
    except: NameError: args.val = None

    # Each line of stdin is a separate kubernetes object that must be parsed
    i = 0
    for line in stdin:

        # First line of stdin has column titles to differentiate object type
        if 'NODES' in stdin_first_line:
            kubernetes_object = KObject(line, "Node")
        else:
            kubernetes_object = KObject(line, "Pod")

        # Only print objects that contain queried string in labels
        if args.val is None:
            print(kubernetes_object)
        else:
            if args.val in '\t'.join(kubernetes_object.labels):
                print(kubernetes_object)
                i += 1
    if i == 0:
        print(f'No occurences of {Colors.FAIL}{args.val}{Colors.ENDC} were found in output.')

Usage: kubectl get nodes | ./filter.py -v 'c5.large'