Update readthedocs-environment.json file when env vars are added/deleted

readthedocs/projects/models.py

@@ -2,6 +2,7 @@
 
 import fnmatch
 import logging
+import json
 import os
 import re
 from urllib.parse import urlparse
@@ -1401,6 +1402,60 @@ class EnvironmentVariable(TimeStampedModel, models.Model):
     def __str__(self):
         return self.name
 
+    def _get_last_built_version(self):
+        """Returns the version that was last built."""
+        version = self.project.versions.all().order_by('-builds__date').first()
+        return version
+
+    def _get_env_json_paths(self, version):
+        """
+        Returns the list containing paths to ``readthedocs-environment.json`` file.
+
+        It returns paths for both python and conda environment.
+        """
+        paths = [
+            os.path.join(
+                self.project.doc_path,
+                'conda',  # if conda env
+                version.slug,
+                'readthedocs-environment.json'
+            ),
+            os.path.join(
+                self.project.doc_path,
+                'envs',  # if python env
+                version.slug,
+                'readthedocs-environment.json'
+            ),
+        ]
+
+        return paths
+
+    def update_env_json(self):
+        """Updates the hash value of ``envvars_hash`` in ``readthedocs-environment.json``."""
+        version = self._get_last_built_version()
+        paths = self._get_env_json_paths(version)
+        for path in paths:
+            if os.path.exists(path):
+                env_vars = self.project.environmentvariable_set.values_list('name', 'value')
+                with open(path, 'r+') as file:
+                    data = json.loads(file.read())
+                    data['envvars_hash'] = hash(tuple(env_vars))
+                    file.seek(0)
+                    file.write(json.dumps(data))
+
     def save(self, *args, **kwargs):  # pylint: disable=arguments-differ
         self.value = shlex_quote(self.value)
-        return super().save(*args, **kwargs)
+        saved = super().save(*args, **kwargs)
+
+        # Updates the ``readthedocs-environment.json`` file.
+        self.update_env_json()
+
+        return saved
+
+    def delete(self, *args, **kwargs):  # pylint: disable=arguments-differ
+        deleted = super().delete(*args, **kwargs)
+
+        # Updates the ``readthedocs-environment.json`` file.
+        self.update_env_json()
+
+        return deleted