nuageinit: Allow the use of network parameters from network-config

To better comply with the cloud-init specification, we need to
support the configuration of network-related parameters from
the network-config file, which is common in most deployments.

Reviewed by:            bapt@
Approved by:            bapt@
Differential Revision:  https://reviews.freebsd.org/D52419

libexec/nuageinit/nuageinit

@@ -582,6 +582,26 @@ local function config2_network(p)
 	routing:close()
 end
 
+local function parse_network_config()
+	local nc_file = ni_path .. "/network-config"
+	local nc_file_attr = lfs.attributes(nc_file)
+	if nc_file_attr == nil then
+		return
+	end
+	local f, err = io.open(nc_file)
+	if err then
+		nuage.err("error parsing nocloud network-config: " .. err)
+	end
+	local obj = yaml.load(f:read("*a"))
+	f:close()
+	if not obj then
+		nuage.err("error parsing nocloud network-config")
+	end
+	local netobj = {}
+	netobj["network"] = obj
+	return netobj
+end
+
 if citype == "config-2" then
 	local parser = ucl.parser()
 	local res, err = parser:parse_file(ni_path .. "/meta_data.json")
@@ -678,7 +698,16 @@ if line == "#cloud-config" then
 	end
 
 	for i = 1, #calls_table do
-		calls_table[i](obj)
+		if citype == "nocloud" and calls_table[i] == network_config then
+			netobj = parse_network_config()
+			if netobj == nil then
+				network_config(obj)
+			else
+				network_config(netobj)
+			end
+		else
+			calls_table[i](obj)
+		end
 	end
 elseif line:sub(1, 2) == "#!" then
 	-- delay for execution at rc.local time --

libexec/nuageinit/nuageinit.7

@@ -182,6 +182,13 @@ configuration in
 .Pa /etc/ssh/sshd_config
 .It Ic network
 Network configuration parameters.
+.Pp
+Specifying the following parameters from a file named
+.Pa network-config
+takes precedence over their specification from the
+.Ic network
+parameter of
+.Pa user-data Ns .
 .Bl -tag -width "ethernets"
 .It Ic ethernets
 Mapping representing a generic configuration for existing network interfaces.