Set containerlab version in installation configuration

The containerlab installation script expects the CONTAINERLAB_VERSION
environment variable to contain the target clab version. We had to
modify the installation script each time we wanted to change the
version; this commit introduces an alternative mechanism and bumps
the containerlab version to 0.68.0:

* The environment variables depending on system defaults are specified
  in the install.yml configuration file
* CONTAINERLAB_VERSION environment variable depends on clab.version
  value (now set to 0.68.0)
* The 'netlab install' command sets the environment variables specified
  in the install.yml configuration file before starting the scripts

Collateral fix:
* 'netlab install' recognized the 'dry-run' flag but did not pass it to
  'external_commands' module.

Fixes #2498

Author: ipspace

netsim/cli/install.py

@@ -14,7 +14,7 @@
 
 from ..utils import log,strings,read
 from ..utils.files import get_moddir
-from . import external_commands,error_and_exit
+from . import external_commands,error_and_exit,set_dry_run
 
 #
 # CLI parser for 'netlab install' command
@@ -84,6 +84,18 @@ def read_config_setup() -> Box:
       error_and_exit(f'Cannot read {str(os_release)}: {str(ex)}')
   return setup
 
+"""
+Adjust installation configuration:
+
+* Update 'env' dictionary from topology variables
+"""
+def adjust_setup(setup: Box, topology: Box, args: argparse.Namespace) -> None:
+  for k,v in setup.env.items():
+    if v in topology.defaults:
+      os.environ[k] = topology.defaults[v]
+      if args.verbose:
+        print(f'ENV: {k}={os.environ[k]}')
+
 """
 check_crazy_pip3: deals with crazy pip3 that thinks installing Python packages in
 local directory will break its sanity
@@ -274,13 +286,17 @@ def run(cli_args: typing.List[str]) -> None:
     return
 
   args = install_parse(cli_args,setup)
+  topology = read.system_defaults()
+  adjust_setup(setup,topology,args)
+
   for script in args.script:
     if script not in setup.scripts:
       error_and_exit(
         f'Unknown installation script {script}',
         more_hints='Run "netlab install" to display the available installation scripts')
 
   set_quiet_flags(args)
+  set_dry_run(args)
   set_sudo_flag()
   install_path = f'{get_moddir()}/install'
   os.environ['PATH'] = install_path + ":" + os.environ['PATH']

netsim/install/containerlab.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 #
-# Install a specific version of Containerlab
-CONTAINERLAB_VERSION="0.62.2"
+# Install a specific version of Containerlab -- it's now set in 'netlab install' before calling this script
+# CONTAINERLAB_VERSION="0.62.2"
 #
 set -e
 REPLACE="--upgrade"

netsim/install/install.yml

@@ -1,3 +1,6 @@
+env:
+  CONTAINERLAB_VERSION: providers.clab.version
+
 scripts:
   ubuntu:
     description: Mandatory and nice-to have Debian/Ubuntu packages

netsim/providers/clab.yml

@@ -6,6 +6,7 @@ config: clab.yml
 lab_prefix: "clab" # Containerlab default, set to "" to remove prefix
 node_config_attributes: [ type, cmd, dns, env, license, ports, startup-delay, restart-policy ]
 template: clab.j2
+version: 0.68.0
 # Preserve env to allow user to configure PATH
 start: sudo -E containerlab deploy --reconfigure -t clab.yml
 stop: sudo -E containerlab destroy --cleanup -t clab.yml