Support for logon/logoff and named sessions

Details:

* Added new 'zhmc session logon/logoff' commands that manage the session
  in a file '.zhmc_sessions.yaml' in the user's home directory.

* Deprecated the existing 'zhmc session create/delete' commands since they
  are less convenient to use compared to the new logon/logoff commands,
  and cannot be used as intended on Windows due to the displayed export/unset
  commands.

* Added a general option '-s' / '--session-name' for specifying the name
  of the session that is managed in the '.zhmc_sessions.yaml' file.
  This allows having multiple sessions to different HMCs open at the same
  time, and selecting them by name. If not specified, the session name is
  'default'.

* The 'session delete' command was changed to unset all ZHMC_* environment
  variables, instead of just ZHMC_SESSION_ID.

* If logon options and ZHMC_* environment variables are both specified,
  the logon options now have precedence and none of the ZHMC_* environment
  variables is used (except ZHMC_PASSWORD). This changes the earlier
  behavior where ZHMC_SESSION_ID was used even when logon options were
  specified.

* The existing testcases for sessions were adjusted for the new behavior.

* Added function testcases for the new _session_file.py module.

* The end2end testcases for the _cmd_sessions.py module were extended with
  new testcases.

Signed-off-by: Andreas Maier <[email protected]>

Makefile

@@ -633,7 +633,8 @@ $(done_dir)/ruff_$(pymn)_$(PACKAGE_LEVEL).done: $(done_dir)/develop_$(pymn)_$(PA
 check_reqs: $(done_dir)/develop_$(pymn)_$(PACKAGE_LEVEL).done minimum-constraints-develop.txt minimum-constraints-install.txt requirements.txt
 	@echo "Makefile: Checking missing dependencies of this package"
 	pip-missing-reqs $(package_name) --requirements-file=requirements.txt
-	pip-missing-reqs $(package_name) --requirements-file=minimum-constraints-install.txt
+# TODO-ZHMC: Enable again, once released version is available
+# pip-missing-reqs $(package_name) --requirements-file=minimum-constraints-install.txt
 	@echo "Makefile: Done checking missing dependencies of this package"
 ifeq ($(PLATFORM),Windows_native)
 # Reason for skipping on Windows is https://github.com/r1chardj0n3s/pip-check-reqs/issues/67

changes/544.2.feature.rst

@@ -0,0 +1,7 @@
+Added support for creating multiple named sessions with a new global option
+'-s' / '--session-name'. It is optional and defaults to the name 'default'.
+This option can be used with 'zhmc session logon/logoff' to create or delete a
+named session, and with any other zhmc command to use a session that has
+previously been created. The 'zhmc session create/delete' commands do not
+support named sessions, because the environment variables that are used to
+store the session data support only a single session.

changes/544.2.incompatible.rst

@@ -0,0 +1,3 @@
+The 'zhmc session create' command now creates a new session without logging off
+from an existing session. Previously, it logged off from an existing session
+and then created a new session.

changes/544.deprecation.rst

@@ -0,0 +1,4 @@
+The 'zhmc session create/delete' commands are now deprecated. They were
+inconvenient to use and did not support Windows out of the box since they
+displayed the export/unset commands to manage the session. Use the new
+'zhmc session logon/logoff' commands instead.

changes/544.feature.rst

@@ -0,0 +1,6 @@
+New 'zhmc session logon/logoff' commands are provided. They manage the session
+in a '.zhmc_sessions.yaml' file in the user's home directory. This is more
+convenient for users compared to the existing 'zhmc session create/delete'
+commands which store the session in environment variables and display the
+export/unset commands to do that. The new commands also support Windows out
+of the box.

changes/544.incompatible.rst

@@ -0,0 +1,5 @@
+If logon options and ZHMC_* environment variables are both provided, the
+logon options now take precedence, and the environment variables are ignored.
+As a result, a provided ZHMC_SESSION_ID variable is now ignored when logon
+options are also provided. Previously, a provided ZHMC_SESSION_ID variable was
+used when logon options were also provided.

minimum-constraints-install.txt

@@ -12,7 +12,8 @@ wheel==0.41.3
 
 # Direct dependencies for install (must be consistent with requirements.txt)
 
-zhmcclient==1.18.0
+# TODO-ZHMC: Switch to released version again, once available
+# zhmcclient==1.19.0
 
 click==8.0.2
 click-repl==0.2

requirements.txt

@@ -6,8 +6,9 @@
 
 # Direct dependencies for install (must be consistent with minimum-constraints-install.txt)
 
-# zhmcclient @ git+https://github.com/zhmcclient/python-zhmcclient.git@master
-zhmcclient>=1.18.0
+# TODO-ZHMC: Switch to released version again, once available
+zhmcclient @ git+https://github.com/zhmcclient/python-zhmcclient.git@master
+# zhmcclient>=1.19.0
 
 # safety 2.2.0 depends on click>=8.0.2
 click>=8.0.2