dcv connect does not work if username is longer than 8 characters

dcv connect hangs for users when their username is longer than 8 characters.

Fixed by https://github.com/aws/aws-parallelcluster-cookbook/pull/2472

The patch is outdated at this point, see attached patch we have
```
--- pcluster_dcv_authenticator.py.bak 2026-04-25 00:00:45.154569647 +0000
+++ pcluster_dcv_authenticator.py 2026-04-25 06:15:14.674231954 +0000
@@ -361,13 +361,17 @@
# TODO change this method if DCV updates his behaviour.
"""
logger.info("Verifying Amazon DCV session validity..")
+
+ # Query by uid rather than username to avoid truncation by ps command
+ uid = subprocess.check_output(["/usr/bin/id", "-u", user]).decode("utf-8").strip() # nosec B603
+
# Remove the first and the last because they are the heading and empty, respectively
# All commands and arguments in this subprocess call are built as literals
- processes = subprocess.check_output(["/bin/ps", "aux"]).decode("utf-8").split("\n")[1:-1] # nosec B603
+ processes = subprocess.check_output(["/bin/ps", "aunx"]).decode("utf-8").split("\n")[1:-1] # nosec B603

# Check the filter is empty
if not next(
- filter(lambda process: DCVAuthenticator.check_dcv_process(process, user, session_id), processes), None
+ filter(lambda process: DCVAuthenticator.check_dcv_process(process, uid, session_id), processes), None
):
raise DCVAuthenticator.IncorrectRequestError("The given session does not exists")
logger.info("The Amazon DCV session is valid.")
@@ -377,21 +381,21 @@
retry(DCVAuthenticator._is_session_valid, func_args=[user, session_id], attempts=20, wait=1)

@staticmethod
- def check_dcv_process(row, user, session_id):
+ def check_dcv_process(row, uid, session_id):
"""Check if there is a dcvagent process running for the given user and for the given session_id."""
# row example:
- # centos 63 0.0 0.0 4348844 3108 ?? Ss 23Jul19 2:32.46 /usr/libexec/dcv/dcvagent --mode full \
+ # 1000 63 0.0 0.0 4348844 3108 ?? Ss 23Jul19 2:32.46 /usr/libexec/dcv/dcvagent --mode full \
# --session-id mysession
- # ubuntu 2949 0.3 0.4 860568 34328 ? Sl 20:10 0:18 /usr/lib/x86_64-linux-gnu/dcv/dcvagent --mode full \
+ # 2000 2949 0.3 0.4 860568 34328 ? Sl 20:10 0:18 /usr/lib/x86_64-linux-gnu/dcv/dcvagent --mode full \
# --session-id mysession
fields = row.split()
command_index = 10
session_name_index = 14
- user_index = 0
+ uid_index = 0

return (
fields[command_index].endswith("/dcv/dcvagent")
- and fields[user_index] == user
+ and fields[uid_index] == uid
and fields[session_name_index] == session_id
)
```