Support 'args' for 'cmd'

Signed-off-by: Trey Dockendorf <tdockendorf@osc.edu>

Author: treydock

README.md

@@ -125,6 +125,9 @@ packages:
 # control command verbosity. By default, it is 'INFO'.
 cmds:
   - cmd: 'echo hello'
+# 'cmd' also supports 'args' that are passed to 'buildah run'
+  - cmd: 'id user'
+    args: ['--volume', '/var/lib/sss:/var/lib/sss:z']
 ```
 
 Then you can use this config file to build a "base" layer (make sure the `S3_ACCESS` and `S3_SECRET` environment variables are set to the S3 credentials if being used):

src/installer.py

@@ -215,7 +215,10 @@ def install_base_commands(self, commands):
         logging.info(f"COMMANDS: running these commands in {self.cname}")
         for c in commands:
             logging.info(c['cmd'])
-            args = [self.cname, '--', 'bash', '-c', c['cmd']]
+            args = []
+            if 'args' in c:
+              args.extend(c['args'])
+            args.extend([self.cname, '--', 'bash', '-c', c['cmd']])
             if 'loglevel' in c:
                 if c['loglevel'].upper() == "INFO":
                     loglevel = logging.info
@@ -239,4 +242,4 @@ def install_base_copyfiles(self, copyfiles):
                     args.extend(o.split())
             logging.info(f['src'] + ' -> ' + f['dest'])
             args +=  [ self.cname, f['src'], f['dest'] ]
-            out=cmd(["buildah","copy"] + args)
+            out=cmd(["buildah","copy"] + args)