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'use strict'
const log = require('./log')
const semver = require('semver')
const { execFile } = require('./util')
const win = process.platform === 'win32'
function getOsUserInfo () {
try {
return require('os').userInfo().username
} catch {}
}
const systemDrive = process.env.SystemDrive || 'C:'
const username = process.env.USERNAME || process.env.USER || getOsUserInfo()
const localAppData = process.env.LOCALAPPDATA || `${systemDrive}\\${username}\\AppData\\Local`
const foundLocalAppData = process.env.LOCALAPPDATA || username
const programFiles = process.env.ProgramW6432 || process.env.ProgramFiles || `${systemDrive}\\Program Files`
const programFilesX86 = process.env['ProgramFiles(x86)'] || `${programFiles} (x86)`
const winDefaultLocationsArray = []
for (const majorMinor of ['311', '310', '39', '38']) {
if (foundLocalAppData) {
winDefaultLocationsArray.push(
`${localAppData}\\Programs\\Python\\Python${majorMinor}\\python.exe`,
`${programFiles}\\Python${majorMinor}\\python.exe`,
`${localAppData}\\Programs\\Python\\Python${majorMinor}-32\\python.exe`,
`${programFiles}\\Python${majorMinor}-32\\python.exe`,
`${programFilesX86}\\Python${majorMinor}-32\\python.exe`
)
} else {
winDefaultLocationsArray.push(
`${programFiles}\\Python${majorMinor}\\python.exe`,
`${programFiles}\\Python${majorMinor}-32\\python.exe`,
`${programFilesX86}\\Python${majorMinor}-32\\python.exe`
)
}
}
class PythonFinder {
static findPython = (...args) => new PythonFinder(...args).findPython()
log = log.withPrefix('find Python')
argsExecutable = ['-c', 'import sys; sys.stdout.buffer.write(sys.executable.encode(\'utf-8\'));']
argsVersion = ['-c', 'import sys; print("%s.%s.%s" % sys.version_info[:3]);']
semverRange = '>=3.6.0'
// These can be overridden for testing:
execFile = execFile
env = process.env
win = win
pyLauncher = 'py.exe'
winDefaultLocations = winDefaultLocationsArray
constructor (configPython) {
this.configPython = configPython
this.errorLog = []
}
// Logs a message at verbose level, but also saves it to be displayed later
// at error level if an error occurs. This should help diagnose the problem.
addLog (message) {
this.log.verbose(message)
this.errorLog.push(message)
}
// Find Python by trying a sequence of possibilities.
// Ignore errors, keep trying until Python is found.
async findPython () {
const SKIP = 0
const FAIL = 1
const toCheck = (() => {
if (this.env.NODE_GYP_FORCE_PYTHON) {
return [{
before: () => {
this.addLog(
'checking Python explicitly set from NODE_GYP_FORCE_PYTHON')
this.addLog('- process.env.NODE_GYP_FORCE_PYTHON is ' +
`"${this.env.NODE_GYP_FORCE_PYTHON}"`)
},
check: () => this.checkCommand(this.env.NODE_GYP_FORCE_PYTHON)
}]
}
const checks = [
{
before: () => {
if (!this.configPython) {
this.addLog(
'Python is not set from command line or npm configuration')
return SKIP
}
this.addLog('checking Python explicitly set from command line or ' +
'npm configuration')
this.addLog('- "--python=" or "npm config get python" is ' +
`"${this.configPython}"`)
},
check: () => this.checkCommand(this.configPython)
},
{
before: () => {
if (!this.env.PYTHON) {
this.addLog('Python is not set from environment variable ' +
'PYTHON')
return SKIP
}
this.addLog('checking Python explicitly set from environment ' +
'variable PYTHON')
this.addLog(`- process.env.PYTHON is "${this.env.PYTHON}"`)
},
check: () => this.checkCommand(this.env.PYTHON)
}
]
if (this.win) {
checks.push({
before: () => {
this.addLog(
'checking if the py launcher can be used to find Python 3')
},
check: () => this.checkPyLauncher()
})
}
checks.push(...[
{
before: () => { this.addLog('checking if "python3" can be used') },
check: () => this.checkCommand('python3')
},
{
before: () => { this.addLog('checking if "python" can be used') },
check: () => this.checkCommand('python')
}
])
if (this.win) {
for (let i = 0; i < this.winDefaultLocations.length; ++i) {
const location = this.winDefaultLocations[i]
checks.push({
before: () => this.addLog(`checking if Python is ${location}`),
check: () => this.checkExecPath(location)
})
}
}
return checks
})()
for (const check of toCheck) {
const before = check.before()
if (before === SKIP) {
continue
}
if (before === FAIL) {
return this.fail()
}
try {
return await check.check()
} catch (err) {
this.log.silly('runChecks: err = %j', (err && err.stack) || err)
}
}
return this.fail()
}
// Check if command is a valid Python to use.
// Will exit the Python finder on success.
// If on Windows, run in a CMD shell to support BAT/CMD launchers.
async checkCommand (command) {
let exec = command
let args = this.argsExecutable
let shell = false
if (this.win) {
// Arguments have to be manually quoted
exec = `"${exec}"`
args = args.map(a => `"${a}"`)
shell = true
}
this.log.verbose(`- executing "${command}" to get executable path`)
// Possible outcomes:
// - Error: not in PATH, not executable or execution fails
// - Gibberish: the next command to check version will fail
// - Absolute path to executable
try {
const execPath = await this.run(exec, args, shell)
this.addLog(`- executable path is "${execPath}"`)
return this.checkExecPath(execPath)
} catch (err) {
this.addLog(`- "${command}" is not in PATH or produced an error`)
throw err
}
}
// Check if the py launcher can find a valid Python to use.
// Will exit the Python finder on success.
// Distributions of Python on Windows by default install with the "py.exe"
// Python launcher which is more likely to exist than the Python executable
// being in the $PATH.
// Because the Python launcher supports Python 2 and Python 3, we should
// explicitly request a Python 3 version. This is done by supplying "-3" as
// the first command line argument. Since "py.exe -3" would be an invalid
// executable for "execFile", we have to use the launcher to figure out
// where the actual "python.exe" executable is located.
async checkPyLauncher () {
this.log.verbose(`- executing "${this.pyLauncher}" to get Python 3 executable path`)
// Possible outcomes: same as checkCommand
try {
const execPath = await this.run(this.pyLauncher, ['-3', ...this.argsExecutable], false)
this.addLog(`- executable path is "${execPath}"`)
return this.checkExecPath(execPath)
} catch (err) {
this.addLog(`- "${this.pyLauncher}" is not in PATH or produced an error`)
throw err
}
}
// Check if a Python executable is the correct version to use.
// Will exit the Python finder on success.
async checkExecPath (execPath) {
this.log.verbose(`- executing "${execPath}" to get version`)
// Possible outcomes:
// - Error: executable can not be run (likely meaning the command wasn't
// a Python executable and the previous command produced gibberish)
// - Gibberish: somehow the last command produced an executable path,
// this will fail when verifying the version
// - Version of the Python executable
try {
const version = await this.run(execPath, this.argsVersion, false)
this.addLog(`- version is "${version}"`)
const range = new semver.Range(this.semverRange)
let valid = false
try {
valid = range.test(version)
} catch (err) {
this.log.silly('range.test() threw:\n%s', err.stack)
this.addLog(`- "${execPath}" does not have a valid version`)
this.addLog('- is it a Python executable?')
throw err
}
if (!valid) {
this.addLog(`- version is ${version} - should be ${this.semverRange}`)
this.addLog('- THIS VERSION OF PYTHON IS NOT SUPPORTED')
throw new Error(`Found unsupported Python version ${version}`)
}
return this.succeed(execPath, version)
} catch (err) {
this.addLog(`- "${execPath}" could not be run`)
throw err
}
}
// Run an executable or shell command, trimming the output.
async run (exec, args, shell) {
const env = Object.assign({}, this.env)
env.TERM = 'dumb'
const opts = { env, shell }
this.log.silly('execFile: exec = %j', exec)
this.log.silly('execFile: args = %j', args)
this.log.silly('execFile: opts = %j', opts)
try {
const [err, stdout, stderr] = await this.execFile(exec, args, opts)
this.log.silly('execFile result: err = %j', (err && err.stack) || err)
this.log.silly('execFile result: stdout = %j', stdout)
this.log.silly('execFile result: stderr = %j', stderr)
return stdout.trim()
} catch (err) {
this.log.silly('execFile: threw:\n%s', err.stack)
throw err
}
}
succeed (execPath, version) {
this.log.info(`using Python version ${version} found at "${execPath}"`)
return execPath
}
fail () {
const errorLog = this.errorLog.join('\n')
const pathExample = this.win
? 'C:\\Path\\To\\python.exe'
: '/path/to/pythonexecutable'
// For Windows 80 col console, use up to the column before the one marked
// with X (total 79 chars including logger prefix, 58 chars usable here):
// X
const info = [
'**********************************************************',
'You need to install the latest version of Python.',
'Node-gyp should be able to find and use Python. If not,',
'you can try one of the following options:',
`- Use the switch --python="${pathExample}"`,
' (accepted by both node-gyp and npm)',
'- Set the environment variable PYTHON',
'- Set the npm configuration variable python:',
` npm config set python "${pathExample}"`,
'For more information consult the documentation at:',
'https://github.com/nodejs/node-gyp#installation',
'**********************************************************'
].join('\n')
this.log.error(`\n${errorLog}\n\n${info}\n`)
throw new Error('Could not find any Python installation to use')
}
}
module.exports = PythonFinder