Implement automatic cloud proxying

This commit is contained in:
Anmol Sethi 2020-09-09 00:03:01 -04:00
parent 916e24e109
commit 55a7e8b56f
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4 changed files with 138 additions and 3 deletions

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@ -82,7 +82,8 @@
"tar-fs": "^2.0.0",
"ws": "^7.2.0",
"xdg-basedir": "^4.0.0",
"yarn": "^1.22.4"
"yarn": "^1.22.4",
"delay": "^4.4.0"
},
"bin": {
"code-server": "out/node/entry.js"

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@ -2,9 +2,14 @@ import { spawn } from "child_process"
import path from "path"
import { logger } from "@coder/logger"
import split2 from "split2"
import delay from "delay"
import fs from "fs"
import { promisify } from "util"
import xdgBasedir from "xdg-basedir"
const coderCloudAgent = path.resolve(__dirname, "../../lib/coder-cloud-agent")
export async function coderCloudExpose(serverName: string): Promise<void> {
const coderCloudAgent = path.resolve(__dirname, "../../lib/coder-cloud-agent")
const agent = spawn(coderCloudAgent, ["link", serverName], {
stdio: ["inherit", "inherit", "pipe"],
})
@ -28,3 +33,125 @@ export async function coderCloudExpose(serverName: string): Promise<void> {
})
})
}
export function coderCloudProxy(addr: string) {
// addr needs to be in host:port format.
// So we trim the protocol.
addr = addr.replace(/^https?:\/\//, "")
if (!xdgBasedir.config) {
return
}
const sessionTokenPath = path.join(xdgBasedir.config, "coder-cloud", "session")
const _proxy = async () => {
await waitForPath(sessionTokenPath)
logger.info("exposing coder-server with coder-cloud")
const agent = spawn(coderCloudAgent, ["proxy", "--code-server-addr", addr], {
stdio: ["inherit", "inherit", "pipe"],
})
agent.stderr.pipe(split2()).on("data", line => {
line = line.replace(/^[0-9-]+ [0-9:]+ [^ ]+\t/, "")
logger.info(line)
})
return new Promise((res, rej) => {
agent.on("error", rej)
agent.on("close", code => {
if (code !== 0) {
rej({
message: `coder cloud agent exited with ${code}`,
})
return
}
res()
})
})
}
const proxy = async () => {
try {
await _proxy()
} catch(err) {
logger.error(err.message)
}
setTimeout(proxy, 3000)
}
proxy()
}
/**
* waitForPath efficiently implements waiting for the existence of a path.
*
* We intentionally do not use fs.watchFile as it is very slow from testing.
* I believe it polls instead of watching.
*
* The way this works is for each level of the path it will check if it exists
* and if not, it will wait for it. e.g. if the path is /home/nhooyr/.config/coder-cloud/session
* then first it will check if /home exists, then /home/nhooyr and so on.
*
* The wait works by first creating a watch promise for the p segment.
* We call fs.watch on the dirname of the p segment. When the dirname has a change,
* we check if the p segment exists and if it does, we resolve the watch promise.
* On any error or the watcher being closed, we reject the watch promise.
*
* Once that promise is setup, we check if the p segment exists with fs.exists
* and if it does, we close the watcher and return.
*
* Now we race the watch promise and a 2000ms delay promise. Once the race
* is complete, we close the watcher.
*
* If the watch promise was the one to resolve, we return.
* Otherwise we setup the watch promise again and retry.
*
* This combination of polling and watching is very reliable and efficient.
*/
async function waitForPath(p: string): Promise<void> {
const segs = p.split(path.sep)
for (let i = 0; i < segs.length; i++) {
const s = path.join("/", ...segs.slice(0, i + 1))
// We need to wait for each segment to exist.
await _waitForPath(s)
}
}
async function _waitForPath(p: string): Promise<void> {
const watchDir = path.dirname(p)
logger.debug(`waiting for ${p}`)
for (;;) {
const w = fs.watch(watchDir)
const watchPromise = new Promise<void>((res, rej) => {
w.on("change", async () => {
if (await promisify(fs.exists)(p)) {
res()
}
})
w.on("close", () => rej(new Error("watcher closed")))
w.on("error", rej)
})
// We want to ignore any errors from this promise being rejected if the file
// already exists below.
watchPromise.catch(() => {})
if (await promisify(fs.exists)(p)) {
// The path exists!
w.close()
return
}
// Now we wait for either the watch promise to resolve/reject or 2000ms.
const s = await Promise.race([watchPromise.then(() => "exists"), delay(2000)])
w.close()
if (s === "exists") {
return
}
}
}

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@ -12,11 +12,11 @@ import { StaticHttpProvider } from "./app/static"
import { UpdateHttpProvider } from "./app/update"
import { VscodeHttpProvider } from "./app/vscode"
import { Args, bindAddrFromAllSources, optionDescriptions, parse, readConfigFile, setDefaults } from "./cli"
import { coderCloudExpose, coderCloudProxy } from "./coder-cloud"
import { AuthType, HttpServer, HttpServerOptions } from "./http"
import { loadPlugins } from "./plugin"
import { generateCertificate, hash, humanPath, open } from "./util"
import { ipcMain, wrap } from "./wrapper"
import { coderCloudExpose } from "./coder-cloud"
process.on("uncaughtException", (error) => {
logger.error(`Uncaught exception: ${error.message}`)
@ -123,6 +123,8 @@ const main = async (args: Args, cliArgs: Args, configArgs: Args): Promise<void>
httpServer.proxyDomains.forEach((domain) => logger.info(` - *.${domain}`))
}
coderCloudProxy(serverAddress!)
if (serverAddress && !options.socket && args.open) {
// The web socket doesn't seem to work if browsing with 0.0.0.0.
const openAddress = serverAddress.replace(/:\/\/0.0.0.0/, "://localhost")

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@ -2525,6 +2525,11 @@ define-property@^2.0.2:
is-descriptor "^1.0.2"
isobject "^3.0.1"
delay@^4.4.0:
version "4.4.0"
resolved "https://registry.yarnpkg.com/delay/-/delay-4.4.0.tgz#71abc745f3ce043fe7f450491236541edec4ad0c"
integrity sha512-txgOrJu3OdtOfTiEOT2e76dJVfG/1dz2NZ4F0Pyt4UGZJryssMRp5vdM5wQoLwSOBNdrJv3F9PAhp/heqd7vrA==
delayed-stream@~1.0.0:
version "1.0.0"
resolved "https://registry.yarnpkg.com/delayed-stream/-/delayed-stream-1.0.0.tgz#df3ae199acadfb7d440aaae0b29e2272b24ec619"