Config v2

config/sys.config

@@ -0,0 +1,12 @@
+[
+    {kernel, [
+        {logger, [
+            {handler, default, logger_std_h, #{
+                formatter =>
+                    {logger_formatter, #{
+                        template => [time, " ", level, ": ", msg, "\n"]
+                    }}
+            }}
+        ]}
+    ]}
+].

ebb.toml

@@ -1,20 +1,11 @@
-# ebb configuration.
-#
-# ebb looks for this file at $EBB_CONFIG, ./ebb.toml, then /etc/ebb/ebb.toml,
-# and refuses to start without it.
-#
-# Features are enabled by presence: a feature runs iff its section exists.
-# When a section is present, all of its keys are required.
+# ebb minimal configuration.
+# unknown keys are rejected
 
 [dhcp]
-# If the ERTS user doesn't have privileges to bind to port 67, this will silently fail.
-listen_port = 67
 
-# IPv4 CIDR of the managed subnet. Leases are allocated from this range.
-range = "172.16.0.0/12"
-
-# How long granted leases last.
-lease_seconds = 3600
+[[dhcp.subnet]]
+cidr = "172.16.0.0/12"
+interface = "pxe0"
 
-# How long an unaccepted OFFER is held before its IP is reclaimed.
-offer_timeout_seconds = 300
+[[dhcp.subnet.pool]]
+range = "172.16.0.0/12"

ebb.toml.sample-full

@@ -0,0 +1,48 @@
+# ebb sample configuration.
+#
+# A section's presence enables it. Unknown keys refuse boot.
+# Keys marked optional may be omitted; defaults are shown.
+# All other keys are required.
+
+[dhcp]
+
+[[dhcp.subnet]]
+cidr = "192.168.1.0/24"
+interface = "eno1"
+
+# Optional. Netboot fields placed in the BOOTP header of replies.
+next_server = "192.168.1.5"
+boot_file = "ipxe.efi"
+
+# Optional. DHCP protocol options; a key's presence means "send it".
+option.routers = "192.168.1.1"
+option.domain_name_servers = "192.168.1.2"
+
+[[dhcp.subnet.pool]]
+range = "192.168.1.50-192.168.1.100"
+lease_seconds = 3600          # optional, default 3600
+offer_timeout_seconds = 300   # optional, default 300
+backend.type = "mem"          # optional, default "mem"
+
+# backend.type selects the storage backend and which backend.* keys apply:
+#   "mem"     no parameters
+#   "file"    requires backend.path
+[[dhcp.subnet.pool]]
+range = "192.168.1.120-192.168.1.200"
+backend.type = "file"
+backend.path = "/var/lib/ebb/leases-eno1"
+
+[[dhcp.subnet]]
+cidr = "10.20.0.0/24"
+interface = "eno2"
+
+[[dhcp.subnet.pool]]
+range = "10.20.0.50-10.20.0.200"
+
+# proxyDHCP: supply PXE boot information on a network whose addressing is
+# owned by an existing DHCP server. Proxy interfaces must not overlap with
+# subnet interfaces.
+[[dhcp.proxy]]
+interface = "eno3"
+next_server = "10.30.0.5"
+boot_file = "ipxe.efi"

ebb.toml.sample-minimal

@@ -0,0 +1,10 @@
+# ebb minimal configuration: serve one pool on one interface.
+
+[dhcp]
+
+[[dhcp.subnet]]
+cidr = "192.168.1.0/24"
+interface = "eno1"
+
+[[dhcp.subnet.pool]]
+range = "192.168.1.50-192.168.1.100"

include/dhcp.hrl

@@ -1,8 +1,14 @@
+-define(DHCP_PORT, 67).
 -define(DHCP_MAGIC_COOKIE, 16#63825363).
 % TODO
 %-define(MAX_LEASE_SECONDS, 86400).
 %-define(MIN_LEASE_SECONDS, 300).
 
+%% Configuration defaults for omitted optional keys.
+-define(DEFAULT_LEASE_SECONDS, 3600).
+-define(DEFAULT_OFFER_TIMEOUT_SECONDS, 300).
+-define(DEFAULT_POOL_BACKEND, "mem").
+
 -record(dhcp_message, {
     % Header
     op :: op(),

rebar.config

@@ -13,7 +13,7 @@
 ]}.
 
 {shell, [
-    %% {config, "config/sys.config"},
+    {config, "config/sys.config"},
     {apps, [ebb]}
 ]}.
 

src/ebb_config.erl

@@ -9,10 +9,7 @@ configuration file is required to boot ebb. The file is resolved in this order:
 """.
 
 -export([load/0, get/1, enabled/1]).
-%% Exported for tests
--export([load_file/1]).
 
--define(PT_KEY, ?MODULE).
 -define(LOCAL_PATH, "ebb.toml").
 -define(SYSTEM_PATH, "/etc/ebb/ebb.toml").
 
@@ -26,100 +23,53 @@ unparseable, or any required key is missing.
 """.
 -spec load() -> ok | {error, io_lib:chars()}.
 load() ->
-    case resolve_path() of
-        {path, Path} ->
-            load_file(Path);
+    maybe
+        {path, File} ?= resolve_path(),
+        logger:notice("Reading configuration from ~p", [File]),
+        {ok, Config} ?= read_toml(File),
+        logger:notice("Parsed configuration as valid TOML"),
+        ok ?= ebb_config_validator:check_structure(Config),
+        logger:notice("Validated configuration structure"),
+        persistent_term:put(?MODULE, atomize(Config))
+    else
         {error, Reason} ->
             {error, Reason}
     end.
 
--doc """
-Load configuration from an explicit path. See also `load/0`.
-""".
--spec load_file(file:name_all()) -> ok | {error, io_lib:chars()}.
-load_file(Path) ->
-    case tomerl:read_file(Path) of
-        {ok, Raw} ->
-            try
-                store(Path, atomize(Raw))
-            catch
-                throw:{unknown_key, Key} ->
-                    {error,
-                        io_lib:format("unknown configuration key \"~s\" in ~s", [
-                            Key, Path
-                        ])}
-            end;
-        {error, Reason} ->
-            {error, io_lib:format("cannot read ~s: ~p", [Path, Reason])}
-    end.
-
-store(Path, Config) ->
-    case missing_keys(Config) of
-        [] ->
-            persistent_term:put(?PT_KEY, Config),
-            logger:notice("Loaded configuration from ~s, enabled features: ~p", [
-                Path, [F || F <- maps:keys(features()), is_map_key(F, Config)]
-            ]),
-            ok;
-        Missing ->
-            {error,
-                io_lib:format("~s is missing required keys: ~s", [
-                    Path, string:join(Missing, ", ")
-                ])}
-    end.
-
 -doc """
 Fetch a configuration value by path, e.g. `get([dhcp, listen_port])`.
-Crashes on unknown paths; see `features/0`.
 """.
 -spec get([atom()]) -> term().
 get(Path) when is_list(Path) ->
-    lists:foldl(fun maps:get/2, persistent_term:get(?PT_KEY), Path).
+    lists:foldl(fun maps:get/2, persistent_term:get(?MODULE), Path).
 
 -doc """
 Features are gated by presence: a feature is enabled iff its section
 exists in the configuration file.
 """.
 -spec enabled(atom()) -> boolean().
 enabled(Feature) ->
-    is_map_key(Feature, persistent_term:get(?PT_KEY)).
+    is_map_key(Feature, persistent_term:get(?MODULE)).
 
 %%--------------------------------------------------------------------
 %% Internal
 %%--------------------------------------------------------------------
 
-%% Known feature sections and the keys each requires when present.
-%% An absent section simply disables the feature.
-features() ->
-    #{
-        dhcp => [listen_port, range, lease_seconds, offer_timeout_seconds]
-    }.
-
-missing_keys(Config) ->
-    maps:fold(
-        fun(Feature, RequiredKeys, Acc) ->
-            case Config of
-                #{Feature := Section} ->
-                    Acc ++
-                        [
-                            atom_to_list(Feature) ++ "." ++ atom_to_list(Key)
-                         || Key <- RequiredKeys, not is_map_key(Key, Section)
-                        ];
-                #{} ->
-                    Acc
-            end
-        end,
-        [],
-        features()
-    ).
-
 resolve_path() ->
     case os:getenv("EBB_CONFIG") of
         false -> search_default_paths();
         "" -> search_default_paths();
         Path -> explicit_path(Path)
     end.
 
+read_toml(File) ->
+    case tomerl:read_file(File) of
+        {ok, Raw} ->
+            {ok, Raw};
+        {error, Reason} ->
+            {error, io_lib:format("cannot read ~s: ~p", [File, Reason])}
+    end.
+
 search_default_paths() ->
     case lists:search(fun filelib:is_regular/1, [?LOCAL_PATH, ?SYSTEM_PATH]) of
         {value, Path} ->
@@ -156,5 +106,7 @@ atomize(Map) when is_map(Map) ->
     );
 atomize(List) when is_list(List) ->
     [atomize(V) || V <- List];
+atomize(Value) when is_binary(Value) ->
+    binary_to_list(Value);
 atomize(Value) ->
     Value.