DOCKER_HOSTをsshで指定しているときにdocker-pyからDockerサーバーにつながらない（一部のバージョン）

起こったこと。

aws-sam-cliからbuildコマンドを呼び出すとエラーが出た

エラー内容

内容は

$ sam build
Traceback (most recent call last):
  File "/opt/homebrew/bin/sam", line 8, in <module>
    sys.exit(cli())
             ^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/decorators.py", line 84, in new_func
    return ctx.invoke(f, obj, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/lib/telemetry/metric.py", line 175, in wrapped
    raise exception  # pylint: disable=raising-bad-type
    ^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/lib/telemetry/metric.py", line 150, in wrapped
    return_value = func(*args, **kwargs)
                   ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/lib/utils/version_checker.py", line 41, in wrapped
    actual_result = func(*args, **kwargs)
                    ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/cli/main.py", line 92, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/commands/build/command.py", line 186, in cli
    do_cli(
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/commands/build/command.py", line 276, in do_cli
    ctx.run()
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/commands/build/build_context.py", line 234, in run
    builder = ApplicationBuilder(
              ^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/samcli/lib/build/app_builder.py", line 157, in __init__
    self._docker_client = docker_client if docker_client else docker.from_env()
                                                              ^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/docker/client.py", line 84, in from_env
    return cls(
           ^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/docker/client.py", line 40, in __init__
    self.api = APIClient(*args, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/docker/api/client.py", line 165, in __init__
    self._custom_adapter = SSHHTTPAdapter(
                           ^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/docker/transport/sshconn.py", line 111, in __init__
    self._connect()
  File "/opt/homebrew/Cellar/aws-sam-cli/1.70.0/libexec/lib/python3.11/site-packages/docker/transport/sshconn.py", line 119, in _connect
    self.ssh_client.connect(**self.ssh_params)
  File "/opt/homebrew/lib/python3.11/site-packages/paramiko/client.py", line 450, in connect
    self._auth(
  File "/opt/homebrew/lib/python3.11/site-packages/paramiko/client.py", line 782, in _auth
    raise SSHException("No authentication methods available")

このような内容で、SSHへの接続でどうやらコケている。
（なお、起こるエラーはAuthentication failed.だったりもした）

ソース周りを調べる

トレースみながら、Pychamでブレークしたりして追った。
Paramikoのあたりでホスト、ユーザー、などは渡っているが、証明書が渡っていない。
次はDocker-pyのソースを調べる。

該当箇所はどうやら
https://github.com/docker/docker-py/blob/4.4.4-release/docker/transport/sshconn.py#L202
このあたり、ssh_configをパースして渡していっているがIdentity fileは渡っていない様子。

なお、5.0.1以降は修正されていた。
https://github.com/docker/docker-py/blob/5.0.1-release/docker/transport/sshconn.py#L209

解決：docker-pyのバージョンを上げればOK

ちゃんとつながって、dockerのinfoも取れた

import docker
client = docker.from_env().info()

>>>>> ......