pm2
Version:
Production process manager for Node.JS applications with a built-in load balancer.
430 lines (367 loc) • 13.3 kB
JavaScript
const { EventEmitter } = require('events')
const Debug = require('debug')
const EWMA = require('./EWMA')
const Histogram = require('./metrics/histogram')
const fclone = (data) => JSON.parse(JSON.stringify(data))
const log = Debug('axm:features:tracing:aggregator')
class TransactionAggregator extends EventEmitter {
constructor () {
super()
this._spanTypes = ['redis', 'mysql', 'pg', 'mongo', 'outbound_http']
this._cache = {
routes: {},
meta: {
trace_count: 0,
http_meter: new EWMA(),
db_meter: new EWMA(),
histogram: new Histogram({ measurement: 'median' }),
db_histograms: {}
}
}
this._privacyRegex = /":(?!\[|{)\\"[^"]*\\"|":(["'])(?:(?=(\\?))\2.)*?\1|":(?!\[|{)[^,}\]]*|":\[[^{]*]/g
this._worker = undefined
}
init (sendInterval) {
sendInterval = sendInterval || 30000
this._worker = setInterval(_ => {
let data = this.prepareAggregationforShipping()
this.emit('packet', { data })
}, sendInterval)
}
destroy () {
if (this._worker !== undefined) {
clearInterval(this._worker)
}
this._cache.routes = {}
}
getAggregation () {
return this._cache
}
validateData (packet) {
if (!packet) {
log('Packet malformated', packet)
return false
}
if (!packet.spans || !packet.spans[0]) {
log('Trace without spans: %s', Object.keys(packet.data))
return false
}
if (!packet.spans[0].labels) {
log('Trace spans without labels: %s', Object.keys(packet.spans))
return false
}
return true
}
/**
* Main method to aggregate and compute stats for traces
*
* @param {Object} packet
*/
aggregate (packet) {
if (this.validateData(packet) === false) return false
// Get http path of current span
let path = packet.spans[0].labels['http/path']
// Cleanup spans
if (process.env.PM2_APM_CENSOR_SPAMS !== '0') {
this.censorSpans(packet.spans)
}
// remove spans with startTime == endTime
packet.spans = packet.spans.filter((span) => {
return span.endTime !== span.startTime
})
// compute duration of child spans
packet.spans.forEach((span) => {
span.mean = Math.round(new Date(span.endTime).getTime() - new Date(span.startTime).getTime())
delete span.endTime
})
// Update app meta (mean_latency, http_meter, db_meter, trace_count)
packet.spans.forEach((span) => {
if (!span.name || !span.kind) return false
if (span.kind === 'RPC_SERVER') {
this._cache.meta.histogram.update(span.mean)
return this._cache.meta.http_meter.update(1)
}
// Override outbount http queries for processing
if (span.labels && span.labels['http/method'] && span.labels['http/status_code']) {
span.labels['service'] = span.name
span.name = 'outbound_http'
}
for (let i = 0; i < this._spanTypes.length; i++) {
if (span.name.indexOf(this._spanTypes[i]) > -1) {
this._cache.meta.db_meter.update(1)
if (!this._cache.meta.db_histograms[this._spanTypes[i]]) {
this._cache.meta.db_histograms[this._spanTypes[i]] = new Histogram({ measurement: 'mean' })
}
this._cache.meta.db_histograms[this._spanTypes[i]].update(span.mean)
break
}
}
})
this._cache.meta.trace_count++
/**
* Handle traces aggregation
*/
if (path[0] === '/' && path !== '/') {
path = path.substr(1, path.length - 1)
}
let matched = this.matchPath(path, this._cache.routes)
if (!matched) {
this._cache.routes[path] = []
this.mergeTrace(this._cache.routes[path], packet)
} else {
this.mergeTrace(this._cache.routes[matched], packet)
}
return this._cache
}
/**
* Merge new trace and compute mean, min, max, count
*
* @param {Object} aggregated previous aggregated route
* @param {Object} trace
*/
mergeTrace (aggregated, trace) {
if (!aggregated || !trace) return
// if the trace doesn't any spans stop aggregation here
if (trace.spans.length === 0) return
// create data structure if needed
if (!aggregated.variances) aggregated.variances = []
if (!aggregated.meta) {
aggregated.meta = {
histogram: new Histogram({ measurement: 'median' }),
meter: new EWMA()
}
}
aggregated.meta.histogram.update(trace.spans[0].mean)
aggregated.meta.meter.update()
const merge = (variance) => {
// no variance found so its a new one
if (variance == null) {
delete trace.projectId
delete trace.traceId
trace.histogram = new Histogram({ measurement: 'median' })
trace.histogram.update(trace.spans[0].mean)
trace.spans.forEach((span) => {
span.histogram = new Histogram({ measurement: 'median' })
span.histogram.update(span.mean)
delete span.mean
})
// parse strackrace
// this.parseStacktrace(trace.spans)
aggregated.variances.push(trace)
} else {
// variance found, merge spans
variance.histogram.update(trace.spans[0].mean)
// update duration of spans to be mean
this.updateSpanDuration(variance.spans, trace.spans)
// delete stacktrace before merging
trace.spans.forEach((span) => {
delete span.labels.stacktrace
})
}
}
// for every variance, check spans same variance
for (let i = 0; i < aggregated.variances.length; i++) {
if (this.compareList(aggregated.variances[i].spans, trace.spans)) {
return merge(aggregated.variances[i])
}
}
// else its a new variance
return merge(null)
}
/**
* Parkour simultaneously both spans list to update value of the first one using value of the second one
* The first should be variance already aggregated for which we want to merge the second one
* The second one is a new trace, so we need to re-compute mean/min/max time for each spans
*/
updateSpanDuration (spans, newSpans) {
for (let i = 0; i < spans.length; i++) {
if (!newSpans[i]) continue
spans[i].histogram.update(newSpans[i].mean)
}
}
/**
* Compare two spans list by going down on each span and comparing child and attribute
*/
compareList (one, two) {
if (one.length !== two.length) return false
for (let i = 0; i < one.length; i++) {
if (one[i].name !== two[i].name) return false
if (one[i].kind !== two[i].kind) return false
if (!one[i].labels && two[i].labels) return false
if (one[i].labels && !two[i].labels) return false
if (one[i].labels.length !== two[i].labels.length) return false
}
return true
}
/**
* Will return the route if we found an already matched route
*/
matchPath (path, routes) {
// empty route is / without the fist slash
if (!path || !routes) return false
if (path === '/') return routes[path] ? path : null
// remove the last slash if exist
if (path[path.length - 1] === '/') {
path = path.substr(0, path.length - 1)
}
// split to get array of segment
path = path.split('/')
// if the path has only one segment, we just need to compare the key
if (path.length === 1) return routes[path[0]] ? routes[path[0]] : null
// check in routes already stored for match
let keys = Object.keys(routes)
for (let i = 0; i < keys.length; i++) {
let route = keys[i]
let segments = route.split('/')
if (segments.length !== path.length) continue
for (let j = path.length - 1; j >= 0; j--) {
// different segment, try to find if new route or not
if (path[j] !== segments[j]) {
// if the aggregator already have matched that segment with a wildcard and the next segment is the same
if (this.isIdentifier(path[j]) && segments[j] === '*' && path[j - 1] === segments[j - 1]) {
return segments.join('/')
// case a let in url match, so we continue because they must be other let in url
} else if (path[j - 1] !== undefined && path[j - 1] === segments[j - 1] && this.isIdentifier(path[j]) && this.isIdentifier(segments[j])) {
segments[j] = '*'
// update routes in cache
routes[segments.join('/')] = routes[route]
delete routes[keys[i]]
return segments.join('/')
} else {
break
}
}
// if finish to iterate over segment of path, we must be on the same route
if (j === 0) return segments.join('/')
}
}
}
/**
* Normalize aggregation
*/
prepareAggregationforShipping () {
let routes = this._cache.routes
const normalized = {
routes: [],
meta: {
trace_count: this._cache.meta.trace_count,
http_meter: Math.round(this._cache.meta.http_meter.rate(1000) * 100) / 100,
db_meter: Math.round(this._cache.meta.db_meter.rate(1000) * 100) / 100,
http_percentiles: {
median: this._cache.meta.histogram.percentiles([0.5])[0.5],
p95: this._cache.meta.histogram.percentiles([0.95])[0.95],
p99: this._cache.meta.histogram.percentiles([0.99])[0.99]
},
db_percentiles: {}
}
}
// compute percentiles for each db spans if they exist
this._spanTypes.forEach((name) => {
let histogram = this._cache.meta.db_histograms[name]
if (!histogram) return
normalized.meta.db_percentiles[name] = histogram.percentiles([0.5])[0.5]
})
Object.keys(routes).forEach((path) => {
let data = routes[path]
// hard check for invalid data
if (!data.variances || data.variances.length === 0) return
// get top 5 variances of the same route
const variances = data.variances.sort((a, b) => {
return b.count - a.count
}).slice(0, 5)
// create a copy without reference to stored one
let routeCopy = {
path: path === '/' ? '/' : '/' + path,
meta: {
min: data.meta.histogram.getMin(),
max: data.meta.histogram.getMax(),
count: data.meta.histogram.getCount(),
meter: Math.round(data.meta.meter.rate(1000) * 100) / 100,
median: data.meta.histogram.percentiles([0.5])[0.5],
p95: data.meta.histogram.percentiles([0.95])[0.95]
},
variances: []
}
variances.forEach((variance) => {
// hard check for invalid data
if (!variance.spans || variance.spans.length === 0) return
// deep copy of variances data
let tmp = {
spans: [],
count: variance.histogram.getCount(),
min: variance.histogram.getMin(),
max: variance.histogram.getMax(),
median: variance.histogram.percentiles([0.5])[0.5],
p95: variance.histogram.percentiles([0.95])[0.95]
}
// get data for each span
variance.spans.forEach((oldSpan) => {
const span = fclone({
name: oldSpan.name,
labels: oldSpan.labels,
kind: oldSpan.kind,
startTime: oldSpan.startTime,
min: oldSpan.histogram ? oldSpan.histogram.getMin() : undefined,
max: oldSpan.histogram ? oldSpan.histogram.getMax() : undefined,
median: oldSpan.histogram ? oldSpan.histogram.percentiles([0.5])[0.5] : undefined
})
tmp.spans.push(span)
})
// push serialized into normalized data
routeCopy.variances.push(tmp)
})
// push the route into normalized data
normalized.routes.push(routeCopy)
})
log(`sending formatted trace to remote endpoint`)
return normalized
}
/**
* Check if the string can be a id of some sort
*
* @param {String} id
*/
isIdentifier (id) {
id = typeof (id) !== 'string' ? id + '' : id
// uuid v1/v4 with/without dash
if (id.match(/[0-9a-f]{8}-[0-9a-f]{4}-[14][0-9a-f]{3}-[0-9a-f]{4}-[0-9a-f]{12}|[0-9a-f]{12}[14][0-9a-f]{19}/i)) {
return true
// if number
} else if (id.match(/\d+/)) {
return true
// if suit of nbr/letters
} else if (id.match(/[0-9]+[a-z]+|[a-z]+[0-9]+/)) {
return true
// if match pattern with multiple char spaced by . - _ @
} else if (id.match(/((?:[0-9a-zA-Z]+[@\-_.][0-9a-zA-Z]+|[0-9a-zA-Z]+[@\-_.]|[@\-_.][0-9a-zA-Z]+)+)/)) {
return true
}
return false
}
/**
* Cleanup trace data
* - delete result(s)
* - replace labels value with a question mark
*
* @param {Object} spans list of span for a trace
*/
censorSpans (spans) {
if (!spans) return log('spans is null')
spans.forEach((span) => {
if (!span.labels) return
delete span.labels.results
delete span.labels.result
delete span.spanId
delete span.parentSpanId
delete span.labels.values
delete span.labels.stacktrace
Object.keys(span.labels).forEach((key) => {
if (typeof (span.labels[key]) === 'string' && key !== 'stacktrace') {
span.labels[key] = span.labels[key].replace(this._privacyRegex, '\": \"?\"')
}
})
})
}
}
module.exports = { TransactionAggregator }