Expected behaviour:

Successfully open a SFTP connection No hostkey for host $host found.

Actual behaviour:

Failure opening SFTP connection

Steps to reproduce:

• Step 1: Run docker container docker build -t flexget . && docker run -v "some/path/to/flexget:/home/flexget/.flexget" -v "some/path/to/ssh:/home/flexget/.ssh" -it flexget

The root of this problem appears to be that pysftp doesn't support port numbers in known_hosts, and is also appears to be abandoned (last update made in 2016). I tried the work around of not defining the port number in known hosts, but ran into unpack requires a buffer of 4 bytes

The known_hosts file is valid, ssh-keygen -l -f ~/some/path/to/ssh/known_hosts -F $host lists the fingerprints correctly.

Apparently Paramiko on which pysftp is based doesn't have these issues, so potentilly converting sftp_client to use Paramiko directly would be a fix.

Config:

templates:
  bar:
    sftp_list:
     host: '{? sftp.host ?}'
      port: '{? sftp.port ?}'
      username: '{? sftp.username ?}'
      private_key: '{? sftp.private_key ?}'
      recursive: True
      get_size: True
      files_only: False
      dirs:
        - "/srv/file"

tasks:

  foo task:
    template:
      - bar

Log:

2022-11-29 10:55:23 DEBUG    sftp_client   foo task        Connecting to $host
2022-11-29 10:55:23 DEBUG    sftp_client   foo task        Caught exception: No hostkey for host $host found.
2022-11-29 10:55:23 WARNING  sftp_client   foo task        Failed to connect to $host; waiting 15 seconds before retrying.

2022-11-29 10:57:27 DEBUG    sftp_client   foo task        Connecting to $host
2022-11-29 10:57:27 DEBUG    sftp_client   foo task        Caught exception: unpack requires a buffer of 4 bytes
2022-11-29 10:57:27 WARNING  sftp_client   foo task        Failed to connect to$host; waiting 15 seconds before retrying.

Additional information:

• FlexGet version: 3.5.6
• Python version: 3.10.6
• Installation method: In Docker container (see below)
• Using daemon (yes/no): no
• OS and version:
• Link to crash log:

Docker container

FROM ubuntu:jammy

RUN \
  echo "**** Create User ****" && \
  groupadd -g 1000 flexget && \
  useradd -m -g 1000 -u 1000 flexget && \
  echo "**** Install Packages ****" && \
  apt-get update && \
  apt-get install -y \ 
     python3-pip && \
  pip3 install \
      --no-cache-dir \
      flexget \ 
      pysftp && \
  apt-get remove -y python3-pip && \
  echo "**** Cleanup ****" && \
  rm -rf /tmp/* \
    /var/lib/apt/lists/* \
    /var/tmp/*

# Contains config.yml
VOLUME /home/flexget/.flexget
# Contains known_hosts
VOLUME /home/flexget/.ssh

USER flexget

CMD /usr/local/bin/flexget --loglevel DEBUG execute