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Add support for extracting datadog tags from metric by RegExp #14

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Add support for extracting datadog tags from metric by RegExp #14

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168 changes: 154 additions & 14 deletions lib/datadog.js
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,30 @@
* datadogApiKey: Your DataDog API key
* datadogPrefix: A global prefix for all metrics
* datadogTags: A global set of tags for all metrics
*
* datadogMetricTagsByRegExp: An object of { RegExpString: [TagNameString1, TagNameString2] }
* where each tag name correspond to a capture group in the regular expression.
* NOTE the strings will be read as a RegExp object, thus backslashes must be escaped.
*
* The following is are example RegExps for popular collectd plugins:
* interface, cpu, tcpconns, load, memory, df.
*
* datadogMetricTagsByRegExp: {
* '^interface\\.(\\S+)\\.(?:if_packets\\.packets|if_octets\\.octets|if_errors\\.errors)\\.(?:rx|tx)$': ['interface_name'],
* '^cpu\\.(\\d+)\\.cpu\\.(\\w+)$': ['cpu_cpu', 'cpu_time'],
* '^tcpconns\\.([\\w-]+)\\.tcp_connections\\.([\\w-]+)$': ['tcpconns_port', 'tcpconns_state'],
* '^load\\.load\\.([\\w-]+)$': ['load_term'],
* '^memory\\.memory\\.([\\w-]+)$': ['memory_type'],
* '^df\\.([\\w-]+?)\\.(?:\\w+?\\.)+([\\w-]+)$': ['df_partition', 'df_type'],
* },
*
* The captured groups will be extracted and truncated from the metric name and be
* reported as datadog tags along with the metric e.g.
*
* 'interface.br-e5f9ab1037e7.if_packets.packets.tx' will be transformed into
* 'interface.if_packets.packets.tx|#interface_name:br-e5f9ab1037e7'
*
* This allows for adding tag dimensions to untagged (e.g. collectd) metrics.
*/

var net = require('net'),
Expand All @@ -28,6 +52,7 @@ var datadogApiKey;
var datadogStats = {};
var datadogPrefix;
var datadogTags;
var datadogMetricTagsByRegExp;

var Datadog = function(api_key, options) {
options = options || {};
Expand Down Expand Up @@ -91,31 +116,42 @@ var flush_stats = function datadog_post_stats(ts, metrics) {
var value;

var key;
var metricNameAndTags;
var metricName;
var metricTags;

// Send counters
for (key in counters) {
value = counters[key];
var valuePerSecond = value / (flushInterval / 1000); // calculate 'per second' rate

metricNameAndTags = get_metric_name_and_tags(key);
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key),
metric: metricName,
points: [[ts, valuePerSecond]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});
}

// Send gauges
for (key in gauges) {
value = gauges[key];

metricNameAndTags = get_metric_name_and_tags(key);
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key),
metric: metricName,
points: [[ts, value]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});
}

Expand Down Expand Up @@ -146,51 +182,137 @@ var flush_stats = function datadog_post_stats(ts, metrics) {
mean = sum / numInThreshold;
}

metricNameAndTags = get_metric_name_and_tags(key + '.mean');
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key + '.mean'),
metric: metricName,
points: [[ts, mean]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});

metricNameAndTags = get_metric_name_and_tags(key);
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key + '.upper'),
metric: metricName + '.upper',
points: [[ts, max]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});

metricNameAndTags = get_metric_name_and_tags(key);
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key + '.upper_' + pctThreshold),
metric: metricName + '.upper_' + pctThreshold,
points: [[ts, maxAtThreshold]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});

metricNameAndTags = get_metric_name_and_tags(key);
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key + '.lower'),
metric: metricName + '.lower',
points: [[ts, min]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});

metricNameAndTags = get_metric_name_and_tags(key);
metricName = metricNameAndTags[0];
metricTags = metricNameAndTags[1];

payload.push({
metric: get_prefix(key + '.count'),
metric: metricName + '.count',
points: [[ts, count]],
type: 'gauge',
host: host,
tags: datadogTags
tags: datadogTags.concat(metricTags)
});
}
}

post_stats(payload);
};

// get_metric_name_and_tags extracts and truncates
// metric-specific tags from the metric name.
var get_metric_name_and_tags = function datadog_get_metric_name_and_tags(key) {
var metricNameAndTags = get_metric_tags_by_regexp(key);
var metricName = metricNameAndTags[0];
var metricTags = metricNameAndTags[1];

// Add prefix if given in configuration.
metricName = get_prefix(metricName);

return [metricName, metricTags];
}

// get_metric_tags_by_regexp attempts to match the given metric key
// with all metric RegExps given in the configuration.
//
// When a RegExp is matched, its captured groups are truncated from the metric
// name and pushed into the metric's specific datadog tags array.
//
// Returns the truncated metric key and its metric-specific tag array.
// If no match is found, the key is returned as-is with an empty tag array.
var get_metric_tags_by_regexp = function datadog_get_metric_tags_by_regexp(key) {
var match;

for (var i = 0; i < datadogMetricTagsByRegExp.length; i++) {
var regExpTags = datadogMetricTagsByRegExp[i];
var re = regExpTags['regExp'];
// RegExp matches start from index i=1 instead of i=0,
// so the tag names that will be matched are offset accordingly.
var tagNames = [ null ].concat(regExpTags['tagNames']);

// Attempt to match current RegExp with given key.
match = re.exec(key);

// If a match is found,
// add the captured groups to the metric's datadog tag array,
// and truncate them from the metric key.
if (match && match.length > 1) {
var mutatedKey = key;
var metricTags = [];

match.forEach(function(groups, j) {
if (j === 0) {
return;
}

var tag = match[j];
var tagName = tagNames[j];

// Add current captured group to tag array.
metricTags.push(tagName + ':' + tag);

// Truncate the captured group from the metric key along with
// it's prefixed or suffixed period character.
mutatedKey = mutatedKey.replace(new RegExp('(' + tag + '\\.?)|(\\.' + tag + '$)'), "");
});

return [mutatedKey, metricTags]
}
}

// If we reached this line, it means no RegExps were matched,
// so we return the original key with no metric-specific datadog tags.
return [key, []]
}

var get_prefix = function datadog_get_prefix(key) {
if (datadogPrefix !== undefined) {
return [datadogPrefix, key].join('.');
Expand All @@ -216,6 +338,7 @@ exports.init = function datadog_init(startup_time, config, events, log) {
datadogApiHost = config.datadogApiHost;
datadogPrefix = config.datadogPrefix;
datadogTags = config.datadogTags;
datadogMetricTagsByRegExp = [];

if (datadogTags === undefined || datadogTags.constructor !== Array || datadogTags.length < 1) {
datadogTags = [];
Expand All @@ -225,6 +348,23 @@ exports.init = function datadog_init(startup_time, config, events, log) {
datadogApiHost = 'https://app.datadoghq.com';
}

// Read metric regexps string into RegExp form.
if (config.datadogMetricTagsByRegExp &&
config.datadogMetricTagsByRegExp.constructor === Object &&
Object.keys(config.datadogMetricTagsByRegExp).length > 0) {

for (var re in config.datadogMetricTagsByRegExp) {
if (config.datadogMetricTagsByRegExp.hasOwnProperty(re)) {
datadogMetricTagsByRegExp.push(
{
'regExp': new RegExp(re),
'tagNames': config.datadogMetricTagsByRegExp[re]
}
);
}
}
}

datadogStats.last_flush = startup_time;
datadogStats.last_exception = startup_time;

Expand Down