dd-trace
Version:
Datadog APM tracing client for JavaScript
229 lines (191 loc) • 6.92 kB
JavaScript
// TODO: Add test with slow or unresponsive agent.
// TODO: Add telemetry for things like dropped requests, errors, etc.
const { Readable } = require('stream')
const http = require('http')
const https = require('https')
const net = require('net')
const zlib = require('zlib')
const { storage } = require('../../../../datadog-core')
const log = require('../../log')
const { parseUrl } = require('./url')
const docker = require('./docker')
const { httpAgent, httpsAgent } = require('./agents')
const {
getMaxAttempts,
getRetryDelay,
isRetriableNetworkError,
markEndpointReached,
} = require('./retry')
const legacyStorage = storage('legacy')
const maxActiveBufferSize = 1024 * 1024 * 64
let activeBufferSize = 0
/**
* @param {string} hostname Host as resolved by {@link parseUrl}; IPv6 is unbracketed (`::1`).
*/
function isLoopbackHost (hostname) {
// The 127.0.0.0/8 block is loopback, but only when the host is an actual IPv4 literal: a
// hostname like `127.evil.com` shares the prefix yet resolves anywhere, so net.isIPv4 gates it.
return hostname === 'localhost' ||
hostname === '::1' ||
(hostname.startsWith('127.') && net.isIPv4(hostname))
}
/**
* @param {Buffer|string|Readable|Array<Buffer|string>} data
* @param {object} options
* @param {(error: Error|null, result: string, statusCode: number) => void} callback
*/
function request (data, options, callback) {
if (!options.headers) {
options.headers = {}
}
if (options.url) {
const url = parseUrl(options.url)
if (url.protocol === 'unix:') {
options.socketPath = url.pathname
} else {
if (!options.path) options.path = url.path
options.protocol = url.protocol
options.hostname = url.hostname // for IPv6 this should be '::1' and not '[::1]'
options.port = url.port
}
}
// Never put the Datadog API key on a cleartext connection to a non-loopback host; that would
// expose it on the wire. Loopback (local agent, dev proxy, tests) is exempt. Strip the key
// rather than drop the request: the agent proxies telemetry with its own key, while an https
// intake URL is required to authenticate agentless traffic.
const hasApiKey = options.headers['dd-api-key'] !== undefined || options.headers['DD-API-KEY'] !== undefined
if (hasApiKey && options.protocol === 'http:' && !isLoopbackHost(options.hostname)) {
log.error(
'Not sending the Datadog API key over a non-TLS connection to %s. Configure an https intake URL.',
options.hostname
)
delete options.headers['dd-api-key']
delete options.headers['DD-API-KEY']
}
if (data instanceof Readable) {
const chunks = []
data
.on('data', (data) => {
chunks.push(data)
})
.on('end', () => {
request(Buffer.concat(chunks), options, callback)
})
.on('error', (err) => {
callback(err)
})
return
}
// The timeout should be kept low to avoid excessive queueing.
const timeout = options.timeout || 2000
const isSecure = options.protocol === 'https:'
const client = isSecure ? https : http
let dataArray = data
if (!Array.isArray(data)) {
dataArray = [data]
}
options.headers['Content-Length'] = byteLength(dataArray)
docker.inject(options.headers)
options.agent = isSecure ? httpsAgent : httpAgent
const onResponse = (res, finalize) => {
markEndpointReached(options)
const chunks = []
res.setTimeout(timeout)
res.on('data', chunk => {
chunks.push(chunk)
})
res.once('end', () => {
finalize()
const buffer = Buffer.concat(chunks)
if (res.statusCode >= 200 && res.statusCode <= 299) {
const isGzip = res.headers['content-encoding'] === 'gzip'
if (isGzip) {
zlib.gunzip(buffer, (err, result) => {
if (err) {
log.error('Could not gunzip response: %s', err.message)
callback(null, '', res.statusCode, res.headers)
} else {
callback(null, result.toString(), res.statusCode, res.headers)
}
})
} else {
callback(null, buffer.toString(), res.statusCode, res.headers)
}
} else {
let errorMessage = ''
try {
const fullUrl = new URL(
options.path,
options.url || options.hostname || `http://localhost:${options.port}`
).href
errorMessage = `Error from ${fullUrl}: ${res.statusCode} ${http.STATUS_CODES[res.statusCode]}.`
} catch {
// ignore error
}
const responseData = buffer.toString()
if (responseData) {
errorMessage += ` Response from the endpoint: "${responseData}"`
}
const error = new log.NoTransmitError(errorMessage)
error.status = res.statusCode
callback(error, null, res.statusCode, res.headers)
}
})
}
// Retries always run via setTimeout so the AsyncLocalStorage store survives
// the gap before socket.connect(); ALS.run() does not call ALS.enterWith()
// outside AsyncContextFrame, so a synchronous re-entry would lose the store.
const attempt = attemptIndex => {
if (!request.writable) {
log.debug('Maximum number of active requests reached: payload is discarded.')
return callback(null)
}
activeBufferSize += options.headers['Content-Length'] ?? 0
legacyStorage.run({ noop: true }, () => {
let finished = false
const finalize = () => {
if (finished) return
finished = true
activeBufferSize -= options.headers['Content-Length'] ?? 0
}
const req = client.request(options, (res) => onResponse(res, finalize))
req.once('close', finalize)
req.once('timeout', finalize)
req.once('error', error => {
finalize()
if (attemptIndex < getMaxAttempts(options) && isRetriableNetworkError(error)) {
// Unref so a pending retry never keeps the host process alive past
// its natural exit point; long-running apps still retry because the
// event loop is held open by their own work.
setTimeout(attempt, getRetryDelay(options, attemptIndex), attemptIndex + 1).unref?.()
} else {
callback(error)
}
})
req.setTimeout(timeout, () => {
try {
if (typeof req.abort === 'function') {
req.abort()
} else {
req.destroy()
}
} catch {
// ignore
}
})
for (const buffer of dataArray) req.write(buffer)
req.end()
})
}
attempt(1)
}
function byteLength (data) {
return data.length > 0 ? data.reduce((prev, next) => prev + Buffer.byteLength(next, 'utf8'), 0) : 0
}
Object.defineProperty(request, 'writable', {
get () {
return activeBufferSize < maxActiveBufferSize
},
})
module.exports = request