Set default logger level from command line (#256)

* Set default logger level from command line

* Return INVALID_REMAP_RULE

* Add tests

* Do string parsing in rcutils

* Set log level after parsing all arguments

Less convenient but seems cleaner

* Document log arg format, custom return code

* Rename function

* Rename argument

* Refactor argument parsing after rebasing to include param files

* Renaming from param files support

* Doc fixup

* __log -> __log_level

* Use RCUTILS_SAFE_FWRITE_TO_STDERR on bad alloc

* doc fixup

* doc fixup

* Document behaviour if multiple __log_level rules found

* Update docblock formatting

* Label all documentation in arguments.c as internal

rcl/Doxyfile

@@ -19,6 +19,10 @@ EXPAND_ONLY_PREDEF     = YES
 PREDEFINED             += RCL_PUBLIC=
 PREDEFINED             += RCL_WARN_UNUSED=
 
+# Uncomment to generate internal documentation.
+ENABLED_SECTIONS       = INTERNAL
+INPUT                  += ./src/rcl/arguments.c
+
 # Tag files that do not exist will produce a warning and cross-project linking will not work.
 TAGFILES += "../../../../doxygen_tag_files/cppreference-doxygen-web.tag.xml=http://en.cppreference.com/w/"
 # Consider changing "latest" to the version you want to reference (e.g. beta1 or 1.0.0)

rcl/include/rcl/arguments.h

@@ -34,6 +34,9 @@ typedef struct rcl_arguments_t
   struct rcl_arguments_impl_t * impl;
 } rcl_arguments_t;
 
+#define RCL_LOG_LEVEL_ARG_RULE "__log_level:="
+#define RCL_PARAM_FILE_ARG_RULE "__params:="
+
 /// Return a rcl_node_t struct with members initialized to `NULL`.
 RCL_PUBLIC
 RCL_WARN_UNUSED
@@ -52,6 +55,12 @@ rcl_get_zero_initialized_arguments(void);
  * Successfully parsed remap rules are stored in the order they were given in `argv`.
  * If given arguments `{"__ns:=/foo", "__ns:=/bar"}` then the namespace used by nodes in this
  * process will be `/foo` and not `/bar`.
+ *
+ * The default log level will be parsed as `__log_level:=level`, where `level` is a name
+ * representing one of the log levels in the `RCUTILS_LOG_SEVERITY` enum, e.g. `info`, `debug`,
+ * `warn`, not case sensitive.
+ * If multiple of these rules are found, the last one parsed will be used.
+ *
  * \sa rcl_remap_topic_name()
  * \sa rcl_remap_service_name()
  * \sa rcl_remap_node_name()

rcl/include/rcl/types.h

@@ -94,5 +94,7 @@ typedef rmw_ret_t rcl_ret_t;
 #define RCL_RET_WRONG_LEXEME 1002
 /// Argument is not a valid parameter rule
 #define RCL_RET_INVALID_PARAM_RULE 1010
+/// Argument is not a valid log level rule
+#define RCL_RET_INVALID_LOG_LEVEL_RULE 1020
 
 #endif  // RCL__TYPES_H_