create a shutdown_command method in distro classes (#567)

Under FreeBSD, we want to use "shutdown -p" for poweroff.

Alpine Linux also has some specificities.

We choose to define a method that returns the shutdown command line to
use, rather than a method that actually does the shutdown. This makes it
easier to have the tests in test_handler_power_state do their
verifications.

Two tests are added for the special behaviours that are known so far.

1 files changed, 8 insertions, 48 deletions

diff --git a/cloudinit/config/cc_power_state_change.py b/cloudinit/config/cc_power_state_change.py
index 6fcb8a7d..b0cfafcd 100644
--- a/cloudinit/config/cc_power_state_change.py
+++ b/cloudinit/config/cc_power_state_change.py
@@ -117,7 +117,7 @@ def check_condition(cond, log=None):
 
 def handle(_name, cfg, cloud, log, _args):
     try:
-        (args, timeout, condition) = load_power_state(cfg, cloud.distro.name)
+        (args, timeout, condition) = load_power_state(cfg, cloud.distro)
         if args is None:
             log.debug("no power_state provided. doing nothing")
             return
@@ -144,19 +144,7 @@ def handle(_name, cfg, cloud, log, _args):
                  condition, execmd, [args, devnull_fp])
 
 
-def convert_delay(delay, fmt=None, scale=None):
-    if not fmt:
-        fmt = "+%s"
-    if not scale:
-        scale = 1
-
-    if delay != "now":
-        delay = fmt % int(int(delay) * int(scale))
-
-    return delay
-
-
-def load_power_state(cfg, distro_name):
+def load_power_state(cfg, distro):
     # returns a tuple of shutdown_command, timeout
     # shutdown_command is None if no config found
     pstate = cfg.get('power_state')
@@ -167,44 +155,16 @@ def load_power_state(cfg, distro_name):
     if not isinstance(pstate, dict):
         raise TypeError("power_state is not a dict.")
 
-    opt_map = {'halt': '-H', 'poweroff': '-P', 'reboot': '-r'}
-
+    modes_ok = ['halt', 'poweroff', 'reboot']
     mode = pstate.get("mode")
-    if mode not in opt_map:
+    if mode not in distro.shutdown_options_map:
         raise TypeError(
             "power_state[mode] required, must be one of: %s. found: '%s'." %
-            (','.join(opt_map.keys()), mode))
-
-    delay = pstate.get("delay", "now")
-    message = pstate.get("message")
-    scale = 1
-    fmt = "+%s"
-    command = ["shutdown", opt_map[mode]]
-
-    if distro_name == 'alpine':
-        # Convert integer 30 or string '30' to '1800' (seconds) as Alpine's
-        # halt/poweroff/reboot commands take seconds rather than minutes.
-        scale = 60
-        # No "+" in front of delay value as not supported by Alpine's commands.
-        fmt = "%s"
-        if delay == "now":
-            # Alpine's commands do not understand "now".
-            delay = "0"
-        command = [mode, "-d"]
-        # Alpine's commands don't support a message.
-        message = None
-
-    try:
-        delay = convert_delay(delay, fmt=fmt, scale=scale)
-    except ValueError as e:
-        raise TypeError(
-            "power_state[delay] must be 'now' or '+m' (minutes)."
-            " found '%s'." % delay
-        ) from e
+            (','.join(modes_ok), mode))
 
-    args = command + [delay]
-    if message:
-        args.append(message)
+    args = distro.shutdown_command(mode=mode,
+                                   delay=pstate.get("delay", "now"),
+                                   message=pstate.get("message"))
 
     try:
         timeout = float(pstate.get('timeout', 30.0))