app_statsd.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 2015, Digium, Inc.
 *
 * Tyler Cambron <tcambron@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */
 
 /*** MODULEINFO
    <depend>res_statsd</depend>
    <defaultenabled>no</defaultenabled>
    <support_level>extended</support_level>
 ***/
 
#include "asterisk.h"
 
#include <math.h>
 
#include "asterisk/module.h"
#include "asterisk/logger.h"
#include "asterisk/app.h"
#include "asterisk/pbx.h"
#include "asterisk/strings.h"
#include "asterisk/statsd.h"
 
/*** DOCUMENTATION
    <application name="StatsD" language="en_US">
        <synopsis>
            Allow statistics to be passed to the StatsD server from the dialplan.
        </synopsis>
        <syntax>
            <parameter name="metric_type" required="true">
                <para>The metric type to be sent to StatsD. Valid metric types
                are 'g' for gauge, 'c' for counter, 'ms' for timer, and 's' for
                sets.</para>
            </parameter>
            <parameter name="statistic_name" required="true">
                <para>The name of the variable to be sent to StatsD. Statistic
                names cannot contain the pipe (|) character.</para>
            </parameter>
            <parameter name="value" required="true">
                <para>The value of the variable to be sent to StatsD. Values
                must be numeric. Values for gauge and counter metrics can be
                sent with a '+' or '-' to update a value after the value has
                been initialized. Only counters can be initialized as negative.
                Sets can send a string as the value parameter, but the string
                cannot contain the pipe character.</para>
            </parameter>
            <parameter name="sample_rate">
                <para>The value of the sample rate to be sent to StatsD. Sample
                rates less than or equal to 0 will never be sent and sample rates
                greater than or equal to 1 will always be sent. Any rate
                between 1 and 0 will be compared to a randomly generated value,
                and if it is greater than the random value, it will be sent.</para>
            </parameter>
        </syntax>
        <description>
            <para>This dialplan application sends statistics to the StatsD
            server specified inside of <literal>statsd.conf</literal>.</para>
        </description>
    </application>
 ***/
 
static const char app[] = "StatsD";
 
/*!
 * \brief Check to ensure the value is within the allowed range.
 *
 * \param value The value of the statistic to be sent to StatsD.
 *
 * This function checks to see if the value given to the StatsD dailplan
 * application is within the allowed range of [-2^63, 2^63] as specified by StatsD.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int value_in_range(const char *value) {
    double numerical_value = strtod(value, NULL);
 
    if (numerical_value < pow(-2, 63) || numerical_value > pow(2, 63)) {
        ast_log(AST_LOG_WARNING, "Value %lf out of range!\n", numerical_value);
        return 1;
    }
 
    return 0;
}
 
/*!
 * \brief Check to ensure the value is within the allowed range.
 *
 * \param value The value of the statistic to be sent to StatsD.
 *
 * This function checks to see if the value given to the StatsD dailplan
 * application is within the allowed range of [0, 2^64] as specified by StatsD.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int non_neg_value_range(const char *value) {
    double numerical_value = strtod(value, NULL);
 
    if (numerical_value < 0 || numerical_value > pow(2, 64)) {
        ast_log(AST_LOG_WARNING, "Value %lf out of range!\n", numerical_value);
        return 1;
    }
 
    return 0;
}
 
/*!
 * \brief Check to ensure the metric type is a valid metric type.
 *
 * \param metric The metric type to be sent to StatsD.
 *
 * This function checks to see if the metric type given to the StatsD dialplan
 * is a valid metric type. Metric types are determined by StatsD.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_metric(const char *metric)
{
    const char *valid_metrics[] = {"g","s","ms","c"};
    int i;
 
    if (ast_strlen_zero(metric)) {
        ast_log(AST_LOG_ERROR, "Missing metric type argument.\n");
        return 1;
    }
 
    for (i = 0; i < ARRAY_LEN(valid_metrics); i++) {
        if (!strcmp(valid_metrics[i], metric)) {
            return 0;
        }
    }
 
    ast_log(AST_LOG_ERROR, "Invalid metric type %s.\n", metric);
 
    return 1;
}
 
/*!
 * \brief Check to ensure that a numeric value is valid.
 *
 * \param numeric_value The numeric value to be sent to StatsD.
 *
 * This function checks to see if a number to be sent to StatsD is actually
 * a valid number. One decimal is allowed.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_numeric(const char *numeric_value) {
    const char *num;
    int decimal_counter = 0;
 
    num = numeric_value;
    while (*num) {
        if (!isdigit(*num++)) {
            if (strstr(numeric_value, ".") != NULL && decimal_counter == 0) {
                decimal_counter++;
                continue;
            }
            ast_log(AST_LOG_ERROR, "%s is not a number!\n", numeric_value);
            return 1;
        }
    }
 
    return 0;
}
 
/*!
 * \brief Determines the actual value of a number by looking for a leading + or -.
 *
 * \param raw_value The entire numeric string to be sent to StatsD.
 *
 * This function checks to see if the numeric string contains valid characters
 * and then isolates the actual number to be sent for validation. Returns the
 * result of the numeric validation.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int determine_actual_value(const char *raw_value) {
    const char *actual_value;
 
    if ((raw_value[0] == '+') || (raw_value[0] == '-')) {
        actual_value = &raw_value[1];
        if (ast_strlen_zero(actual_value)) {
            ast_log(AST_LOG_ERROR, "Value argument %s only contains a sign"
                " operator.\n", raw_value);
            return 1;
        }
    } else {
        actual_value = &raw_value[0];
    }
 
    return validate_numeric(actual_value);
}
 
/*!
 * \brief Check to ensure the statistic name is valid.
 *
 * \param name The variable name to be sent to StatsD.
 *
 * This function checks to see if the statistic name given to the StatsD
 * dialplan application is valid by ensuring that the name does not have any
 * invalid characters.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_name(const char *name)
{
    if (ast_strlen_zero(name) || (strstr(name, "|") != NULL)) {
        ast_log(AST_LOG_ERROR, "Statistic name %s is missing or contains a pipe (|)"
            " character.\n", name);
        return 1;
    }
 
    return 0;
}
 
 
/*!
 * \brief Calls the appropriate functions to validate a gauge metric.
 *
 * \param statistic_name The statistic name to be sent to StatsD.
 * \param value The value to be sent to StatsD.
 *
 * This function calls other validating functions to correctly validate each
 * input based on allowable input for a gauge metric.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_metric_type_gauge(const char *statistic_name, const char *value) {
 
    if (ast_strlen_zero(value)) {
        ast_log(AST_LOG_ERROR, "Missing value argument.\n");
        return 1;
    }
 
    if (validate_name(statistic_name) || determine_actual_value(value)
        || value_in_range(value)) {
        return 1;
    }
 
    return 0;
}
 
/*!
 * \brief Calls the appropriate functions to validate a counter metric.
 *
 * \param statistic_name The statistic name to be sent to StatsD.
 * \param value The value to be sent to StatsD.
 *
 * This function calls other validating functions to correctly validate each
 * input based on allowable input for a counter metric.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_metric_type_counter(const char *statistic_name, const char *value) {
 
    if (ast_strlen_zero(value)) {
        ast_log(AST_LOG_ERROR, "Missing value argument.\n");
        return 1;
    }
 
    if (validate_name(statistic_name) || determine_actual_value(value)
        || value_in_range(value)) {
        return 1;
    }
 
    return 0;
}
 
/*!
 * \brief Calls the appropriate functions to validate a timer metric.
 *
 * \param statistic_name The statistic name to be sent to StatsD.
 * \param value The value to be sent to StatsD.
 *
 * This function calls other validating functions to correctly validate each
 * input based on allowable input for a timer metric.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_metric_type_timer(const char *statistic_name, const char *value) {
 
    if (ast_strlen_zero(value)) {
        ast_log(AST_LOG_ERROR, "Missing value argument.\n");
        return 1;
    }
 
    if (validate_name(statistic_name) || validate_numeric(value)
        || non_neg_value_range(value)) {
        return 1;
    }
 
    return 0;
}
 
/*!
 * \brief Calls the appropriate functions to validate a set metric.
 *
 * \param statistic_name The statistic name to be sent to StatsD.
 * \param value The value to be sent to StatsD.
 *
 * This function calls other validating functions to correctly validate each
 * input based on allowable input for a set metric.
 *
 * \retval zero on success.
 * \retval 1 on error.
 */
static int validate_metric_type_set(const char *statistic_name, const char *value) {
    if (ast_strlen_zero(value)) {
        ast_log(AST_LOG_ERROR, "Missing value argument.\n");
        return 1;
    }
 
    if (validate_name(statistic_name)) {
        return 1;
    }
 
    if (strstr(value, "|") != NULL) {
        ast_log(AST_LOG_ERROR, "Pipe (|) character is not allowed for value %s"
            " in a set metric.\n", value);
        return 1;
    }
 
    return 0;
}
 
static int statsd_exec(struct ast_channel *chan, const char *data)
{
    char *stats;
    double numerical_rate = 1.0;
 
    AST_DECLARE_APP_ARGS(args,
            AST_APP_ARG(metric_type);
            AST_APP_ARG(statistic_name);
            AST_APP_ARG(value);
            AST_APP_ARG(sample_rate);
    );
 
    if (!data) {
        ast_log(AST_LOG_ERROR, "No parameters were provided. Correct format is "
            "StatsD(metric_type,statistic_name,value[,sample_rate]). Sample rate is the "
            "only optional parameter.\n");
        return 1;
    }
 
    stats = ast_strdupa(data);
    AST_STANDARD_APP_ARGS(args, stats);
 
    if (validate_metric(args.metric_type)) {
        return 1;
    }
 
    if (!strcmp(args.metric_type, "g")) {
        if (validate_metric_type_gauge(args.statistic_name, args.value)) {
            ast_log(AST_LOG_ERROR, "Invalid input for a gauge metric.\n");
            return 1;
        }
    }
    else if (!strcmp(args.metric_type, "c")) {
        if (validate_metric_type_counter(args.statistic_name, args.value)) {
            ast_log(AST_LOG_ERROR, "Invalid input for a counter metric.\n");
            return 1;
        }
    }
    else if (!strcmp(args.metric_type, "ms")) {
        if (validate_metric_type_timer(args.statistic_name, args.value)) {
            ast_log(AST_LOG_ERROR, "Invalid input for a timer metric.\n");
            return 1;
        }
    }
    else if (!strcmp(args.metric_type, "s")) {
        if (validate_metric_type_set(args.statistic_name, args.value)) {
            ast_log(AST_LOG_ERROR, "Invalid input for a set metric.\n");
            return 1;
        }
    }
 
    if (args.sample_rate) {
 
        if (validate_numeric(args.sample_rate)) {
            return 1;
        }
 
        numerical_rate = strtod(args.sample_rate, NULL);
    }
 
    ast_statsd_log_string(args.statistic_name, args.metric_type, args.value,
        numerical_rate);
 
    return 0;
}
 
static int unload_module(void)
{
    return ast_unregister_application(app);
}
 
static int load_module(void)
{
    return ast_register_application_xml(app, statsd_exec);
}
 
AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "StatsD Dialplan Application",
    .support_level = AST_MODULE_SUPPORT_EXTENDED,
    .load = load_module,
    .unload = unload_module,
    .requires = "res_statsd",
);