Prints a PlantUML diagram that shows the DAG of the GitLab pipeline

gitlab_dag_diagram.py

#!/usr/bin/env python3
"""Prints a PlantUML diagram that shows the DAG of the GitLab pipeline"""

import sys
import yaml
from pprint import pprint

def merge(user, default):
    if isinstance(user,dict) and isinstance(default,dict):
        for k,v in default.items():
            if k not in user:
                user[k] = v
            else:
                user[k] = merge(user[k],v)
    return user

merged = {}
with open('.gitlab-ci.yml') as file:
    tmp = yaml.load(file)
    filenames = tmp['include']
    filenames.append('.gitlab-ci.yml')
    
for filename in filenames:
    with open(f'./{filename}') as file:
        tmp = yaml.load(file)
        merge(merged, tmp)
        tmp = {}

print('@startuml')
print('left to right direction')
jobs = {k: v for k, v in merged.items() if k not in ['image', 'services', 'stages', 'include']}
branches = {}
all_changes = [v['only']['changes'] for k, v in jobs.items() if type(v.get('only')) is dict and v.get('only', {}).get('changes', {}) and not v.get('needs')]  # gather all `only:changes`
for changes in all_changes:
    branches[str(changes)] = []  # list of e.g. {"kibana/**/*": deployKibanaDev}

if len(sys.argv) > 1:
  for stage in merged['stages']:  # This groups by stage, which looks nice but may be misleading
      matching_jobs = [k for k, v in jobs.items() if v['stage'] == stage]
      print(f'partition "{stage}" {{')
      for job in matching_jobs:
          needs = merged[job].get('needs')
          if needs:
              for need in needs:
                  print(f'  "{need}" --> "{job}" ')
          else:
              print(f'  (*) --> "{job}" ')
      print("}")
else:
  for job in jobs:
      changes = []
      needs = merged[job].get('needs')
      try:
          changes = merged[job]['only']['changes']
      except:
          pass
      if needs:  # if `needs:` exists, `only:changes` is implied from transitive depenencies
          for need in needs:
              print(f'"{need}" --> "{job}" ')
      else:
          if changes:  # first job, has `only:changes`
              branches[str(changes)].append(job)
          else:  # first job, triggers off all commits
              print(f'(*) --> "{job}" ')
if branches:
    for branch in branches:
        print(f'(*) --> if "{branch}" then')
        for job in branches[branch]:
            print(f'  --> "{job}"')
            print(f'else')  # this is probably not how `else` is supposed to be used but it looks good.
        print('}')
print('@enduml')

python3 ../../../plantuml.py
Traceback (most recent call last):
File "../../../plantuml.py", line 5, in
import yaml
ModuleNotFoundError: No module named 'yaml'

did
pip install pyyaml
and
pip3 install virtualenv [google recommend]

python3 -m pip install pyyaml fixed my issue