Psycopg <class 'IndexError'> tuple index out of range

[IlyaSukhanov]

  File "/var/task/sqlalchemy/engine/default.py", line 412, in connect
    return self.dbapi.connect(*cargs, **cparams)
  File "/var/task/aws_xray_sdk/ext/psycopg2/patch.py", line 20, in _xray_traced_connect
    dbname = kwargs['dbname'] if 'dbname' in kwargs else re.search(r'dbname=(\S+)\b', args[0]).groups()[0]

[IlyaSukhanov]

I'm presuming the host dbname port user extraction logic does not support all the formats of connection strings that psycopg supports.

[IlyaSukhanov]

psycopg2.connect() Supports 3 variants of operation:

1. psycopg2.connect("dbname=test user=postgres password=secret")
2. psycopg2.connect(dbname="test", user="postgres", password="secret")
3. psycopg2.connect()

Variant 3 is ok if arguments are passed via env-vars:
Any other connection parameter supported by the client library/server can be passed either in the connection string or as a keyword. The PostgreSQL documentation contains the complete list of the supported parameters. Also note that the same parameters can be passed to the client library using environment variables.

aws-xray-sdk-python does not support variant 3 or mix of variant 2 and 3.

[IlyaSukhanov]

It may not be obvious but use of patch_all() or patch of psycopg will cause any code error out and stack trace when opening connection to database. This is quite serious bug.

[IlyaSukhanov]

After some more digging around turns out problem was different but solution remained the same.

Psycopg supports passing of database name both as dbname and as database. SQL Alchemy uses the database variety triggering the bug.
https://github.com/psycopg/psycopg2/blob/master/lib/__init__.py#L96

There may still be a way to use method 3 as described in comment above but its not obvious. And psycopg will error out if there are no arguments on connect. https://github.com/psycopg/psycopg2/blob/master/lib/__init__.py#L122 Maybe if you set port via kwarg / dsn but the rest via env var?

[revmischa]

Getting this error when database is localhost

[Tankanow]

Is this still an issue or was this solved with 180de75?

[haotianw465]

@Tankanow this is fixed in the commit you mentioned. We will close this issue once the commit is released (which should be soon).

[haotianw465]

The fix is released in 2.2.0 https://pypi.org/project/aws-xray-sdk/. Closing.