Validate log.*.formatter.depth and document its floor

The `log.*.formatter.depth` mappings accept any integer, so a
misconfiguration such as `depth = 0` or a negative value passes schema
validation and is then silently clamped to 5. This is inconsistent with
the sibling `log.error_logger_format_depth` mapping, which rejects
non-positive values.

Add a `formatter_depth` validator that accepts `unlimited` or a positive
integer, and apply it to all four formatter depth mappings (console,
exchange, syslog, file). Document in `translate_generic_conf/2` that an
explicit depth is floored at 5, matching OTP's
`logger_formatter:get_depth/1`, so the clamp is no longer undocumented.

Author: lukebakken

deps/rabbit/priv/schema/rabbit.schema

@@ -1661,7 +1661,8 @@ end}.
 ]}.
 {mapping, "log.console.formatter.depth", "rabbit.log.console.formatter", [
     {default, unlimited},
-    {datatype, [{atom, unlimited}, integer]}
+    {datatype, [{atom, unlimited}, integer]},
+    {validators, ["formatter_depth"]}
 ]}.
 {mapping, "log.console.formatter.plaintext.format", "rabbit.log.console.formatter", [
     {default, "$time [$level] $pid $msg"},
@@ -1704,7 +1705,8 @@ end}.
 ]}.
 {mapping, "log.exchange.formatter.depth", "rabbit.log.exchange.formatter", [
     {default, unlimited},
-    {datatype, [{atom, unlimited}, integer]}
+    {datatype, [{atom, unlimited}, integer]},
+    {validators, ["formatter_depth"]}
 ]}.
 {mapping, "log.exchange.formatter.plaintext.format", "rabbit.log.exchange.formatter", [
     {default, "$time [$level] $pid $msg"},
@@ -1763,7 +1765,8 @@ end}.
 ]}.
 {mapping, "log.syslog.formatter.depth", "rabbit.log.syslog.formatter", [
     {default, unlimited},
-    {datatype, [{atom, unlimited}, integer]}
+    {datatype, [{atom, unlimited}, integer]},
+    {validators, ["formatter_depth"]}
 ]}.
 {mapping, "log.syslog.formatter.plaintext.format", "rabbit.log.syslog.formatter", [
     {default, "$msg"},
@@ -2005,7 +2008,8 @@ end}.
 ]}.
 {mapping, "log.file.formatter.depth", "rabbit.log.file.formatter", [
     {default, unlimited},
-    {datatype, [{atom, unlimited}, integer]}
+    {datatype, [{atom, unlimited}, integer]},
+    {validators, ["formatter_depth"]}
 ]}.
 {mapping, "log.file.formatter.plaintext.format", "rabbit.log.file.formatter", [
     {default, "$time [$level] $pid $msg"},
@@ -3122,6 +3126,12 @@ fun(Int) when is_integer(Int) ->
     Int >= 1
 end}.
 
+{validator, "formatter_depth", "should be positive integer or 'unlimited'",
+fun(unlimited) -> true;
+   (Int) when is_integer(Int) -> Int >= 1;
+   (_) -> false
+end}.
+
 {validator, "positive_16_bit_unsigned_integer", "number should be between 1 and 65535",
  fun(Int) when is_integer(Int) ->
          (Int >= 1) and (Int =< 16#ff_ff)

deps/rabbitmq_prelaunch/src/rabbit_prelaunch_early_logging.erl

@@ -269,7 +269,8 @@ translate_generic_conf(Var, Conf) ->
     %% sub-terms to `...'. `unlimited' (or an unset key) means "no
     %% explicit depth"; in that case we fall back to the deprecated
     %% `error_logger_format_depth' kernel variable, the same way OTP's
-    %% `logger_formatter:get_depth/1' does.
+    %% `logger_formatter:get_depth/1' does. As in OTP, an explicit depth
+    %% is floored at 5, so configured values below 5 are raised to 5.
     Depth = case cuttlefish:conf_get(Var ++ ".depth", Conf, unlimited) of
                 unlimited -> error_logger:get_format_depth();
                 D         -> max(5, D)