Import python venv for stability

2026-02-15 21:24:16 -08:00
parent 1343e93a59
commit 7d784705c9
4997 changed files with 1628270 additions and 0 deletions
@@ -0,0 +1,128 @@
+from peewee import *
+from playhouse.sqlite_ext import JSONField
+
+
+class BaseChangeLog(Model):
+    timestamp = DateTimeField(constraints=[SQL('DEFAULT CURRENT_TIMESTAMP')])
+    action = TextField()
+    table = TextField()
+    primary_key = IntegerField()
+    changes = JSONField()
+
+
+class ChangeLog(object):
+    # Model class that will serve as the base for the changelog. This model
+    # will be subclassed and mapped to your application database.
+    base_model = BaseChangeLog
+
+    # Template for the triggers that handle updating the changelog table.
+    # table: table name
+    # action: insert / update / delete
+    # new_old: NEW or OLD (OLD is for DELETE)
+    # primary_key: table primary key column name
+    # column_array: output of build_column_array()
+    # change_table: changelog table name
+    template = """CREATE TRIGGER IF NOT EXISTS %(table)s_changes_%(action)s
+    AFTER %(action)s ON %(table)s
+    BEGIN
+        INSERT INTO %(change_table)s
+            ("action", "table", "primary_key", "changes")
+        SELECT
+            '%(action)s', '%(table)s', %(new_old)s."%(primary_key)s", "changes"
+        FROM (
+            SELECT json_group_object(
+                col,
+                json_array(
+                    case when json_valid("oldval") then json("oldval")
+                        else "oldval" end,
+                    case when json_valid("newval") then json("newval")
+                        else "newval" end)
+                ) AS "changes"
+            FROM (
+                SELECT json_extract(value, '$[0]') as "col",
+                       json_extract(value, '$[1]') as "oldval",
+                       json_extract(value, '$[2]') as "newval"
+                FROM json_each(json_array(%(column_array)s))
+                WHERE "oldval" IS NOT "newval"
+            )
+        );
+    END;"""
+
+    drop_template = 'DROP TRIGGER IF EXISTS %(table)s_changes_%(action)s'
+
+    _actions = ('INSERT', 'UPDATE', 'DELETE')
+
+    def __init__(self, db, table_name='changelog'):
+        self.db = db
+        self.table_name = table_name
+
+    def _build_column_array(self, model, use_old, use_new, skip_fields=None):
+        # Builds a list of SQL expressions for each field we are tracking. This
+        # is used as the data source for change tracking in our trigger.
+        col_array = []
+        for field in model._meta.sorted_fields:
+            if field.primary_key:
+                continue
+
+            if skip_fields is not None and field.name in skip_fields:
+                continue
+
+            column = field.column_name
+            new = 'NULL' if not use_new else 'NEW."%s"' % column
+            old = 'NULL' if not use_old else 'OLD."%s"' % column
+
+            if isinstance(field, JSONField):
+                # Ensure that values are cast to JSON so that the serialization
+                # is preserved when calculating the old / new.
+                if use_old: old = 'json(%s)' % old
+                if use_new: new = 'json(%s)' % new
+
+            col_array.append("json_array('%s', %s, %s)" % (column, old, new))
+
+        return ', '.join(col_array)
+
+    def trigger_sql(self, model, action, skip_fields=None):
+        assert action in self._actions
+        use_old = action != 'INSERT'
+        use_new = action != 'DELETE'
+        cols = self._build_column_array(model, use_old, use_new, skip_fields)
+        return self.template % {
+            'table': model._meta.table_name,
+            'action': action,
+            'new_old': 'NEW' if action != 'DELETE' else 'OLD',
+            'primary_key': model._meta.primary_key.column_name,
+            'column_array': cols,
+            'change_table': self.table_name}
+
+    def drop_trigger_sql(self, model, action):
+        assert action in self._actions
+        return self.drop_template % {
+            'table': model._meta.table_name,
+            'action': action}
+
+    @property
+    def model(self):
+        if not hasattr(self, '_changelog_model'):
+            class ChangeLog(self.base_model):
+                class Meta:
+                    database = self.db
+                    table_name = self.table_name
+            self._changelog_model = ChangeLog
+
+        return self._changelog_model
+
+    def install(self, model, skip_fields=None, drop=True, insert=True,
+                update=True, delete=True, create_table=True):
+        ChangeLog = self.model
+        if create_table:
+            ChangeLog.create_table()
+
+        actions = list(zip((insert, update, delete), self._actions))
+        if drop:
+            for _, action in actions:
+                self.db.execute_sql(self.drop_trigger_sql(model, action))
+
+        for enabled, action in actions:
+            if enabled:
+                sql = self.trigger_sql(model, action, skip_fields)
+                self.db.execute_sql(sql)