[GitHub] [airflow] ashb commented on a change in pull request #5975: [AIRFLOW-5368] Display DAG from the CLI

[GitBox <gi...@apache.org>]

ashb commented on a change in pull request #5975: [AIRFLOW-5368] Display DAG from the CLI
URL: https://github.com/apache/airflow/pull/5975#discussion_r320185707
 
 

 ##########
 File path: airflow/bin/cli.py
 ##########
 @@ -441,6 +442,33 @@ def set_is_paused(is_paused, args):
     print("Dag: {}, paused: {}".format(args.dag_id, str(is_paused)))
 
 
+def show_dag(args):
+    dag = get_dag(args)
+    dot = render_dag(dag)
+    if args.save:
+        filename, _, fileformat = args.save.rpartition('.')
+        dot.render(filename=filename, format=fileformat, cleanup=True)
+        print("File {} saved".format(args.save))
+    elif args.imgcat:
+        data = dot.pipe(format='png')
+        try:
+            proc = subprocess.Popen("imgcat", stdout=subprocess.PIPE, stdin=subprocess.PIPE)
+        except OSError as e:
+            if e.errno == errno.ENOENT:
+                raise AirflowException(
+                    "Failed to execute. Make sure the imgcat executables are on your systems \'PATH\'"
+                )
+            else:
+                raise
+        out, err = proc.communicate(data)
+        if out:
+            print(out.decode('utf-8'))
+        if err:
+            print(err.decode('utf-8'))
+    else:
+        print(dot.source)
 
 Review comment:
   Given this also prints logging to stdout from airflow startup it might be worth adding a way to save the dot contents to a file. (Unless `dot.render(format="dot")` already works for that?)

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