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python: move Python detection to its own file
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PR-URL: #1815
Reviewed-By: Christian Clauss <cclauss@me.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
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@joaocgreis
joaocgreis committed Jul 11, 2019
1 parent bb92c76 commit 7e7fce3
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Showing 3 changed files with 297 additions and 287 deletions.
286 changes: 2 additions & 284 deletions lib/configure.js
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Original file line number Diff line number Diff line change
Expand Up @@ -4,15 +4,12 @@ const fs = require('graceful-fs')
const path = require('path')
const log = require('npmlog')
const os = require('os')
const semver = require('semver')
const mkdirp = require('mkdirp')
const cp = require('child_process')
const extend = require('util')._extend // eslint-disable-line
const processRelease = require('./process-release')
const win = process.platform === 'win32'
const findNodeDirectory = require('./find-node-directory')
const msgFormat = require('util').format
const logWithPrefix = require('./util').logWithPrefix
var findPython = require('./find-python')
if (win) {
var findVisualStudio = require('./find-visualstudio')
}
Expand Down Expand Up @@ -375,287 +372,8 @@ function findAccessibleSync (logprefix, dir, candidates) {
return undefined
}

function PythonFinder (configPython, callback) {
this.callback = callback
this.configPython = configPython
this.errorLog = []
}

PythonFinder.prototype = {
log: logWithPrefix(log, 'find Python'),
argsExecutable: [ '-c', 'import sys; print(sys.executable);' ],
argsVersion: [ '-c', 'import sys; print("%s.%s.%s" % sys.version_info[:3]);' ],
semverRange: '>=2.6.0 <3.0.0',

// These can be overridden for testing:
execFile: cp.execFile,
env: process.env,
win: win,
pyLauncher: 'py.exe',
defaultLocation: path.join(process.env.SystemDrive || 'C:', 'Python27',
'python.exe'),

// 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: function 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.
findPython: function findPython () {
const SKIP = 0; const FAIL = 1
const toCheck = [
{
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 ' +
`"${this.configPython}"`)
},
check: this.checkCommand,
arg: this.configPython
},
{
before: () => {
if (!this.env.PYTHON) {
this.addLog('Python is not set from environment variable PYTHON')
return SKIP
}
this.addLog(
'checking Python explicitly set from environment variable PYTHON')
this.addLog(`- process.env.PYTHON is "${this.env.PYTHON}"`)
},
check: this.checkCommand,
arg: this.env.PYTHON
},
{
before: () => { this.addLog('checking if "python2" can be used') },
check: this.checkCommand,
arg: 'python2'
},
{
before: () => { this.addLog('checking if "python" can be used') },
check: this.checkCommand,
arg: 'python'
},
{
before: () => {
if (!this.win) {
// Everything after this is Windows specific
return FAIL
}
this.addLog(
'checking if the py launcher can be used to find Python 2')
},
check: this.checkPyLauncher
},
{
before: () => {
this.addLog(
'checking if Python 2 is installed in the default location')
},
check: this.checkExecPath,
arg: this.defaultLocation
}
]

function runChecks (err) {
this.log.silly('runChecks: err = %j', (err && err.stack) || err)

const check = toCheck.shift()
if (!check) {
return this.fail()
}

const before = check.before.apply(this)
if (before === SKIP) {
return runChecks.apply(this)
}
if (before === FAIL) {
return this.fail()
}

const args = [ runChecks.bind(this) ]
if (check.arg) {
args.unshift(check.arg)
}
check.check.apply(this, args)
}

runChecks.apply(this)
},

// 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.
checkCommand: function checkCommand (command, errorCallback) {
var exec = command
var args = this.argsExecutable
var shell = false
if (this.win) {
// Arguments have to be manually quoted
exec = `"${exec}"`
args = args.map(a => `"${a}"`)
shell = true
}

this.log.verbose(`- executing "${command}" to get executable path`)
this.run(exec, args, shell, function (err, execPath) {
// Possible outcomes:
// - Error: not in PATH, not executable or execution fails
// - Gibberish: the next command to check version will fail
// - Absolute path to executable
if (err) {
this.addLog(`- "${command}" is not in PATH or produced an error`)
return errorCallback(err)
}
this.addLog(`- executable path is "${execPath}"`)
this.checkExecPath(execPath, errorCallback)
}.bind(this))
},

// 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 $PATH.
// Because the Python launcher supports all versions of Python, we have to
// explicitly request a Python 2 version. This is done by supplying "-2" as
// the first command line argument. Since "py.exe -2" would be an invalid
// executable for "execFile", we have to use the launcher to figure out
// where the actual "python.exe" executable is located.
checkPyLauncher: function checkPyLauncher (errorCallback) {
this.log.verbose(
`- executing "${this.pyLauncher}" to get Python 2 executable path`)
this.run(this.pyLauncher, [ '-2', ...this.argsExecutable ], false,
function (err, execPath) {
// Possible outcomes: same as checkCommand
if (err) {
this.addLog(
`- "${this.pyLauncher}" is not in PATH or produced an error`)
return errorCallback(err)
}
this.addLog(`- executable path is "${execPath}"`)
this.checkExecPath(execPath, errorCallback)
}.bind(this))
},

// Check if a Python executable is the correct version to use.
// Will exit the Python finder on success.
checkExecPath: function checkExecPath (execPath, errorCallback) {
this.log.verbose(`- executing "${execPath}" to get version`)
this.run(execPath, this.argsVersion, false, function (err, version) {
// Possible outcomes:
// - Error: executable can not be run (likely meaning the command wasn't
// a Python executable and the previous command produced gibberish)
// - Gibberish: somehow the last command produced an executable path,
// this will fail when verifying the version
// - Version of the Python executable
if (err) {
this.addLog(`- "${execPath}" could not be run`)
return errorCallback(err)
}
this.addLog(`- version is "${version}"`)

const range = semver.Range(this.semverRange)
var 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?')
return errorCallback(err)
}

if (!valid) {
this.addLog(`- version is ${version} - should be ${this.semverRange}`)
this.addLog('- THIS VERSION OF PYTHON IS NOT SUPPORTED')
return errorCallback(new Error(
`Found unsupported Python version ${version}`))
}
this.succeed(execPath, version)
}.bind(this))
},

// Run an executable or shell command, trimming the output.
run: function run (exec, args, shell, callback) {
var env = extend({}, this.env)
env.TERM = 'dumb'
const opts = { env: env, shell: shell }

this.log.silly('execFile: exec = %j', exec)
this.log.silly('execFile: args = %j', args)
this.log.silly('execFile: opts = %j', opts)
try {
this.execFile(exec, args, opts, execFileCallback.bind(this))
} catch (err) {
this.log.silly('execFile: threw:\n%s', err.stack)
return callback(err)
}

function execFileCallback (err, stdout, stderr) {
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)
if (err) {
return callback(err)
}
const execPath = stdout.trim()
callback(null, execPath)
}
},

succeed: function succeed (execPath, version) {
this.log.info(`using Python version ${version} found at "${execPath}"`)
process.nextTick(this.callback.bind(null, null, execPath))
},

fail: function 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 2.7.',
'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`)
process.nextTick(this.callback.bind(null, new Error(
'Could not find any Python 2 installation to use')))
}
}

function findPython (configPython, callback) {
var finder = new PythonFinder(configPython, callback)
finder.findPython()
}

module.exports = configure
module.exports.test = {
PythonFinder: PythonFinder,
findAccessibleSync: findAccessibleSync,
findPython: findPython
findAccessibleSync: findAccessibleSync
}
module.exports.usage = 'Generates ' + (win ? 'MSVC project files' : 'a Makefile') + ' for the current module'
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