refactor(userspace/engine): increase const coherence of falco engine

Signed-off-by: Jason Dellaluce <jasondellaluce@gmail.com>

userspace/engine/falco_engine.cpp

@@ -67,7 +67,7 @@ uint32_t falco_engine::engine_version()
 	return (uint32_t) FALCO_ENGINE_VERSION;
 }
 
-falco_source* falco_engine::find_source(const std::string& name)
+const falco_source* falco_engine::find_source(const std::string& name) const
 {
 	auto ret = m_sources.at(name);
 	if(!ret)
@@ -77,7 +77,7 @@ falco_source* falco_engine::find_source(const std::string& name)
 	return ret;
 }
 
-falco_source* falco_engine::find_source(std::size_t index)
+const falco_source* falco_engine::find_source(std::size_t index) const
 {
 	auto ret = m_sources.at(index);
 	if(!ret)
@@ -94,7 +94,7 @@ static std::string fieldclass_key(const gen_event_filter_factory::filter_fieldcl
 	return fld_info.name + fld_info.shortdesc;
 }
 
-void falco_engine::list_fields(std::string &source, bool verbose, bool names_only, bool markdown)
+void falco_engine::list_fields(std::string &source, bool verbose, bool names_only, bool markdown) const
 {
 	// Maps from field class name + short desc to list of event
 	// sources for which this field class can be used.
@@ -102,14 +102,14 @@ void falco_engine::list_fields(std::string &source, bool verbose, bool names_onl
 
 	// Do a first pass to group together classes that are
 	// applicable to multiple event sources.
-	for(auto &it : m_sources)
+	for(const auto &it : m_sources)
 	{
 		if(source != "" && source != it.name)
 		{
 			continue;
 		}
 
-		for(auto &fld_class : it.filter_factory->get_fields())
+		for(const auto &fld_class : it.filter_factory->get_fields())
 		{
 			fieldclass_event_sources[fieldclass_key(fld_class)].insert(it.name);
 		}
@@ -121,7 +121,7 @@ void falco_engine::list_fields(std::string &source, bool verbose, bool names_onl
 
 	// In the second pass, actually print info, skipping duplicate
 	// field classes and also printing info on supported sources.
-	for(auto &it : m_sources)
+	for(const auto &it : m_sources)
 	{
 		if(source != "" && source != it.name)
 		{
@@ -234,7 +234,7 @@ void falco_engine::enable_rule(const string &substring, bool enabled, const stri
 	uint16_t ruleset_id = find_ruleset_id(ruleset);
 	bool match_exact = false;
 
-	for(auto &it : m_sources)
+	for(const auto &it : m_sources)
 	{
 		if(enabled)
 		{
@@ -252,7 +252,7 @@ void falco_engine::enable_rule_exact(const string &rule_name, bool enabled, cons
 	uint16_t ruleset_id = find_ruleset_id(ruleset);
 	bool match_exact = true;
 
-	for(auto &it : m_sources)
+	for(const auto &it : m_sources)
 	{
 		if(enabled)
 		{
@@ -269,7 +269,7 @@ void falco_engine::enable_rule_by_tag(const set<string> &tags, bool enabled, con
 {
 	uint16_t ruleset_id = find_ruleset_id(ruleset);
 
-	for(auto &it : m_sources)
+	for(const auto &it : m_sources)
 	{
 		if(enabled)
 		{
@@ -302,7 +302,7 @@ uint64_t falco_engine::num_rules_for_ruleset(const std::string &ruleset)
 {
 	uint16_t ruleset_id = find_ruleset_id(ruleset);
 	uint64_t ret = 0;
-	for (auto &src : m_sources)
+	for (const auto &src : m_sources)
 	{
 		ret += src.ruleset->enabled_count(ruleset_id);
 	}
@@ -315,7 +315,7 @@ void falco_engine::evttypes_for_ruleset(std::string &source, std::set<uint16_t>
 }
 
 std::shared_ptr<gen_event_formatter> falco_engine::create_formatter(const std::string &source,
-								    const std::string &output)
+								    const std::string &output) const
 {
 	return find_source(source)->formatter_factory->create_formatter(output);
 }
@@ -369,7 +369,7 @@ std::size_t falco_engine::add_source(const std::string &source,
 	return m_sources.insert(src, source);
 }
 
-void falco_engine::describe_rule(string *rule)
+void falco_engine::describe_rule(string *rule) const
 {
 	static const char* rule_fmt = "%-50s %s\n";
 	fprintf(stdout, rule_fmt, "Rule", "Description");
@@ -390,7 +390,7 @@ void falco_engine::describe_rule(string *rule)
 	}
 }
 
-void falco_engine::print_stats()
+void falco_engine::print_stats() const
 {
 	string out;
 	m_rule_stats_manager.format(m_rules, out);
@@ -398,7 +398,7 @@ void falco_engine::print_stats()
 	fprintf(stdout, "%s", out.c_str());
 }
 
-bool falco_engine::is_source_valid(const std::string &source)
+bool falco_engine::is_source_valid(const std::string &source) const
 {
 	return m_sources.at(source) != nullptr;
 }
@@ -443,7 +443,7 @@ void falco_engine::interpret_load_result(std::unique_ptr<load_result>& res,
 
 bool falco_engine::check_plugin_requirements(
 		const std::vector<plugin_version_requirement>& plugins,
-		std::string& err)
+		std::string& err) const
 {
 	for (const auto &req : m_rule_loader.required_plugin_versions())
 	{
@@ -484,9 +484,9 @@ bool falco_engine::check_plugin_requirements(
 	return true;
 }
 
-void falco_engine::complete_rule_loading()
+void falco_engine::complete_rule_loading() const
 {
-	for (auto &src : m_sources)
+	for (const auto &src : m_sources)
 	{
 		src.ruleset->on_loading_complete();
 	}
@@ -508,7 +508,7 @@ void falco_engine::set_extra(string &extra, bool replace_container_info)
 	m_replace_container_info = replace_container_info;
 }
 
-inline bool falco_engine::should_drop_evt()
+inline bool falco_engine::should_drop_evt() const
 {
 	if(m_sampling_multiplier == 0)
 	{

userspace/engine/falco_engine.h

@@ -56,7 +56,7 @@ public:
 
 	// Print to stdout (using printf) a description of each field supported by this engine.
 	// If source is non-empty, only fields for the provided source are printed.
-	void list_fields(std::string &source, bool verbose, bool names_only, bool markdown);
+	void list_fields(std::string &source, bool verbose, bool names_only, bool markdown) const;
 
 	//
 	// Load rules either directly or from a filename.
@@ -98,7 +98,7 @@ public:
 	// Internally, this can be used to release unused resources before starting
 	// processing events with process_event().
 	//
-	void complete_rule_loading();
+	void complete_rule_loading() const;
 
 	// Only load rules having this priority or more severe.
 	void set_min_priority(falco_common::priority_type priority);
@@ -121,12 +121,12 @@ public:
 	// Print details on the given rule. If rule is NULL, print
 	// details on all rules.
 	//
-	void describe_rule(std::string *rule);
+	void describe_rule(std::string *rule) const;
 
 	//
 	// Print statistics on how many events matched each rule.
 	//
-	void print_stats();
+	void print_stats() const;
 
 	//
 	// Set the sampling ratio, which can affect which events are
@@ -200,7 +200,7 @@ public:
 
 	// Return whether or not there is a valid filter/formatter
 	// factory for this source.
-	bool is_source_valid(const std::string &source);
+	bool is_source_valid(const std::string &source) const;
 
 	//
 	// Given an event source and ruleset, fill in a bitset
@@ -216,7 +216,7 @@ public:
 	// event.
 	//
 	std::shared_ptr<gen_event_formatter> create_formatter(const std::string &source,
-							      const std::string &output);
+							      const std::string &output) const;
 
 	// The rule loader definition is aliased as it is exactly what we need
 	typedef rule_loader::plugin_version_info plugin_version_requirement;
@@ -230,7 +230,7 @@ public:
 	//
 	bool check_plugin_requirements(
 		const std::vector<plugin_version_requirement>& plugins,
-		std::string& err);
+		std::string& err) const;
 
 private:
 
@@ -246,15 +246,15 @@ private:
 
 	indexed_vector<falco_source> m_sources;
 
-	falco_source* find_source(std::size_t index);
+	const falco_source* find_source(std::size_t index) const;
-	falco_source* find_source(const std::string& name);
+	const falco_source* find_source(const std::string& name) const;
 
 	//
 	// Determine whether the given event should be matched at all
 	// against the set of rules, given the current sampling
 	// ratio/multiplier.
 	//
-	inline bool should_drop_evt();
+	inline bool should_drop_evt() const;
 
 	rule_loader m_rule_loader;
 	indexed_vector<falco_rule> m_rules;

userspace/engine/formats.cpp

@@ -20,7 +20,7 @@ limitations under the License.
 #include "falco_engine.h"
 #include "banned.h" // This raises a compilation error when certain functions are used
 
-falco_formats::falco_formats(std::shared_ptr<falco_engine> engine,
+falco_formats::falco_formats(std::shared_ptr<const falco_engine> engine,
 			     bool json_include_output_property,
 			     bool json_include_tags_property)
 	: m_falco_engine(engine),
@@ -35,7 +35,7 @@ falco_formats::~falco_formats()
 
 string falco_formats::format_event(gen_event *evt, const std::string &rule, const std::string &source,
 				   const std::string &level, const std::string &format, std::set<std::string> &tags,
-				   const std::string &hostname)
+				   const std::string &hostname) const
 {
 	string line;
 
@@ -132,7 +132,7 @@ string falco_formats::format_event(gen_event *evt, const std::string &rule, cons
 }
 
 map<string, string> falco_formats::get_field_values(gen_event *evt, const std::string &source,
-						    const std::string &format)
+						    const std::string &format) const
 {
 	std::shared_ptr<gen_event_formatter> formatter;
 

userspace/engine/formats.h

@@ -24,20 +24,20 @@ limitations under the License.
 class falco_formats
 {
 public:
-	falco_formats(std::shared_ptr<falco_engine> engine,
+	falco_formats(std::shared_ptr<const falco_engine> engine,
 		      bool json_include_output_property,
 		      bool json_include_tags_property);
 	virtual ~falco_formats();
 
 	std::string format_event(gen_event *evt, const std::string &rule, const std::string &source,
 				 const std::string &level, const std::string &format, std::set<std::string> &tags,
-				 const std::string &hostname);
+				 const std::string &hostname) const;
 
 	map<string, string> get_field_values(gen_event *evt, const std::string &source,
-					     const std::string &format);
+					     const std::string &format) const ;
 
 protected:
-	std::shared_ptr<falco_engine> m_falco_engine;
+	std::shared_ptr<const falco_engine> m_falco_engine;
 	bool m_json_include_output_property;
 	bool m_json_include_tags_property;
 };