217 add functionality to send callback messages

oda_api/api.py

@@ -36,6 +36,7 @@
 import requests
 import ast
 import json
+import re
 
 try:
     # compatibility in some remaining environments
@@ -1339,3 +1340,49 @@
                 p.meta_data = p.meta
 
         return d
+
+class ProgressReporter(object):
+    """
+    The class allows to report task progress to end user
+    """
+    def __init__(self):
+        self._callback = None
+        callback_file = ".oda_api_callback"  # perhaps it would be better to define this constant in a common lib
+        if not os.path.isfile(callback_file):
+            return
+        with open(callback_file, 'r') as file:
+            self._callback = file.read().strip()
+
+    @property
+    def enabled(self):
+        return self._callback is not None
+
+    def report_progress(self, stage: str=None, progress: int=50, substage: str=None, subprogress: int=None, message:str=None):
+        """
+        Report progress via callback URL
+        :param stage: current stage description string
+        :param progress: current stage progress in %
+        :param substage: current substage description string
+        :param subprogress: current substage progress in %
+        :param message: message to pass
+        """
+        callback_payload = dict(stage=stage, progress=progress, substage=substage, subprogress=subprogress, message=message)
+        callback_payload = {k: v for k, v in callback_payload.items() if v is not None}
+
+        if not self.enabled:
+            logger.info('no callback registered, skipping')
+            return
+
+        logger.info('will perform callback: %s', self._callback)
+
+        if re.match('^file://', self._callback):
+            with open(self._callback.replace('file://', ''), "w") as f:
+                json.dump(callback_payload, f)
+            logger.info('stored callback in a file %s', self._callback)
+
+        elif re.match('^https?://', self._callback):
+            r = requests.get(self._callback, params=callback_payload)
+            logger.info('callback %s returns %s : %s', self._callback, r, r.text)
+
+        else:
+            raise NotImplementedError

tests/test_progress_report.py

@@ -0,0 +1,34 @@
+from oda_api.api import ProgressReporter
+import os
+import json
+
+callback_file = ".oda_api_callback"
+
+def test_progress_reporter_disabled():
+    if os.path.isfile(callback_file):
+        os.remove(callback_file)
+    # if callback is not available
+    pr = ProgressReporter()
+    assert not pr.enabled
+    pr.report_progress(stage='simulation', progress=50, substage='spectra', subprogress=30, message='some message')
+
+def test_progress_reporter_enabled():
+    # if callback is available
+    try:
+        dump_file = 'callback'
+        with open(callback_file, 'w') as file:
+            print(f'file://{os.getcwd()}/{dump_file}', file=file)
+
+        pr = ProgressReporter()
+        assert pr.enabled
+        params = dict(stage='simulation', progress=50, substage='spectra', subprogress=30, message='some message')
+        pr.report_progress(**params)
+        with open(dump_file) as json_file:
+            passed_params = json.load(json_file)
+            assert len([k for k in passed_params.keys() if k not in params]) == 0
+    finally:
+        if os.path.isfile(callback_file):
+            os.remove(callback_file)
+        if os.path.isfile(dump_file):
+            os.remove(dump_file)
+