Masking: Add possibility to reload rules

Documentation/Filters/Masking.md

@@ -241,3 +241,19 @@ string should be a MariaDB account string, that is, `%` is a wildcard.
     ]
 }
 ```
+
+## Module commands
+
+Read [Module Commands](../Reference/Module-Commands.md) documentation for details about module commands.
+
+The masking filter supports the following module commands.
+
+### `reload`
+
+Reload the rules from the rules file. The new rules are taken into use
+only if the loading succeeds without any errors.
+```
+MaxScale> call command masking reload MyMaskingFilter
+```
+`MyMaskingFilter` refers to a particular filter section in the
+MariaDB MaxScale configuration file.

server/modules/filter/masking/maskingfilter.cc

@@ -14,17 +14,67 @@
 #define MXS_MODULE_NAME "masking"
 #include "maskingfilter.hh"
 #include <maxscale/gwdirs.h>
+#include <maxscale/modulecmd.h>
 #include "maskingrules.hh"
 
 using std::auto_ptr;
 using std::string;
 
+namespace
+{
+
+char VERSION_STRING[] = "V1.0.0";
+
+/**
+ * Implement "call command masking reload ..."
+ *
+ * @param pArgs  The arguments of the command.
+ *
+ * @return True, if the command was handled.
+ */
+bool masking_command_reload(const MODULECMD_ARG* pArgs)
+{
+    ss_dassert(pArgs->argc == 2);
+    ss_dassert(MODULECMD_GET_TYPE(&pArgs->argv[0].type) == MODULECMD_ARG_OUTPUT);
+    ss_dassert(MODULECMD_GET_TYPE(&pArgs->argv[1].type) == MODULECMD_ARG_FILTER);
+
+    DCB* pDcb = pArgs->argv[0].value.dcb;
+    ss_dassert(pDcb);
+
+    const FILTER_DEF* pFilterDef = pArgs->argv[1].value.filter;
+    ss_dassert(pFilterDef);
+
+    if (strcmp(pFilterDef->module, "masking") == 0)
+    {
+        MaskingFilter* pFilter = reinterpret_cast<MaskingFilter*>(pFilterDef->filter);
+
+        MXS_EXCEPTION_GUARD(pFilter->reload(pDcb));
+    }
+    else
+    {
+        dcb_printf(pDcb, "Filter %s exists, but it is not a masking filter.", pFilterDef->name);
+    }
+
+    return true;
+}
+
+}
+
 //
 // Global symbols of the Module
 //
 
 extern "C" MXS_MODULE* MXS_CREATE_MODULE()
 {
+    static modulecmd_arg_type_t reload_argv[] =
+    {
+        { MODULECMD_ARG_OUTPUT, "The output dcb" },
+        { MODULECMD_ARG_FILTER, "Masking name" }
+    };
+
+    modulecmd_register_command("masking", "reload", masking_command_reload,
+                               MXS_ARRAY_NELEMS(reload_argv), reload_argv);
+
     MXS_NOTICE("Masking module %s initialized.", VERSION_STRING);
 
     static MXS_MODULE info =
@@ -104,6 +154,23 @@ std::tr1::shared_ptr<MaskingRules> MaskingFilter::rules() const
     return m_sRules;
 }
 
+void MaskingFilter::reload(DCB* pOut)
+{
+    auto_ptr<MaskingRules> sRules = MaskingRules::load(m_config.rules_file().c_str());
+
+    if (sRules.get())
+    {
+        m_sRules = sRules;
+
+        dcb_printf(pOut, "Rules reloaded.\n");
+    }
+    else
+    {
+        dcb_printf(pOut, "Could not reload the rules. Check the log file for more "
+                   "detailed information.\n");
+    }
+}
+
 // static
 bool MaskingFilter::process_params(char **pzOptions, CONFIG_PARAMETER *ppParams, Config& config)
 {

server/modules/filter/masking/maskingfilter.hh

@@ -37,6 +37,8 @@ public:
 
     static uint64_t getCapabilities();
 
+    void reload(DCB* pOut);
+
     SMaskingRules rules() const;
 
 private: