Node.js: Python not found exception due to node-sass and node-gyp

158
votes

Suddenly in one of my jenkins environment build has started failing, while in local machine it seems to be working fine as i have python installed,

From the logs i was able to detect that the problem is with internal dependency that is node-gyp v3.5.0 from node-sass v3.8.0 when i researched by visiting this about node-gyp and found the prerequisite that Python needs to be installed.

So my question is that what version of node-sass can i install to bypass this or is there a better solution as my build was running fine till this morning on the same environment.

Node v5.10.1

ERROR LOG

gyp verb check python checking for Python executable "python2" in the PATH
gyp verb `which` failed Error: not found: python2
gyp verb `which` failed     at getNotFoundError (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:13:12)
gyp verb `which` failed     at F (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:68:19)
gyp verb `which` failed     at E (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:80:29)
gyp verb `which` failed     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:89:16
gyp verb `which` failed     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\isexe\index.js:44:5
gyp verb `which` failed     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\isexe\windows.js:29:5
gyp verb `which` failed     at FSReqWrap.oncomplete (fs.js:82:15)
gyp verb `which` failed  python2 { [Error: not found: python2] code: 'ENOENT' }
gyp verb check python checking for Python executable "python" in the PATH
gyp verb `which` failed Error: not found: python
gyp verb `which` failed     at getNotFoundError (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:13:12)
gyp verb `which` failed     at F (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:68:19)
gyp verb `which` failed     at E (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:80:29)
gyp verb `which` failed     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\which\which.js:89:16
gyp verb `which` failed     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\isexe\index.js:44:5
gyp verb `which` failed     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\isexe\windows.js:29:5
gyp verb `which` failed     at FSReqWrap.oncomplete (fs.js:82:15)
gyp verb `which` failed  python { [Error: not found: python] code: 'ENOENT' }
gyp verb could not find "python". checking python launcher 
gyp verb could not find "python". guessing location 
gyp verb ensuring that file exists: C:\Python27\python.exe
gyp ERR! configure error 
gyp ERR! stack Error: Can't find Python executable "python", you can set the PYTHON env variable.
gyp ERR! stack     at Object.failNoPython (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\node-gyp\lib\configure.js:454:19)
gyp ERR! stack     at Object.<anonymous> (C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\node-gyp\lib\configure.js:480:16)
gyp ERR! stack     at C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\graceful-fs\polyfills.js:284:29
gyp ERR! stack     at FSReqWrap.oncomplete (fs.js:82:15)
gyp ERR! System Windows_NT 6.3.9600
gyp ERR! command "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files (x86)\\Jenkins\\jobs\\NdbSite-hot-fix-Manual-PreBuild\\workspace\\src\\NdbSite.UI\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild" "--verbose" "--libsass_ext=" "--libsass_cflags=" "--libsass_ldflags=" "--libsass_library="
gyp ERR! cwd C:\Program Files (x86)\Jenkins\jobs\NdbSite-hot-fix-Manual-PreBuild\workspace\src\NdbSite.UI\node_modules\node-sass
gyp ERR! node -v v5.10.1
gyp ERR! node-gyp -v v3.5.0
gyp ERR! not ok 
Build failed

Any thoughts are much appreciated, Thanks.

20
node.jsnode-gypnode-sass
You want to install angular, so you also want the angular-cli tools, then you need python2 and on windows, you also need msbuild.exe which comes with visualstudio2017. So, you first need to install the visual studio installer tool. Then you have so much tools installed, that you need to configure the versions of your tools in npm. - bvdb

20 Answers

25
votes

Node-sass tries to download the binary for you platform when installing. Node 5 is supported by 3.8 https://github.com/sass/node-sass/releases/tag/v3.8.0 If your Jenkins can't download the prebuilt binary, then you need to follow the platform requirements on Node-gyp README (Python2, VS or MSBuild, ...) If possible I'd suggest updating your Node to at least 6 since 5 isn't supported by Node anymore. If you want to upgrade to 8, you'll need to update node-sass to 4.5.3

231
votes

so this happened to me on windows recently. I fix it by following the following steps using a PowerShell with admin privileges:

  1. delete node_modulesfolder
  2. running npm install --global windows-build-tools with administrative privilege. (in my case need restart - and restart without ask!!!)
  3. reinstalling node modules or node-sass with npm install
46
votes

The error message means that it cannot locate your python executable or binary.

In many cases, it's installed at c:\python27. if it's not installed yet, you can install it with npm install --global windows-build-tools, which will only work if it hasn't been installed yet.

Adding it to the environment variables does not always work. A better alternative, is to just set it in the npm config.

npm config set python c:\python27\python.exe

24
votes

My machine is Windows 10, I've faced similar problems while tried to compile SASS using node-sass package. My node version is v10.16.3 and npm version is 6.9.0

The way that I resolved the problem:

  1. At first delete package-lock.json file and node_modules/ folder.
  2. Open Windows PowerShell as Administrator.
  3. Run the command npm i -g node-sass.
  4. After that, go to the project folder and run npm install
  5. And finally, run the SASS compiling script, in my case, it is npm run build:css

And it works!!

16
votes

I had to:

Delete node_modules
Uninstall/reinstall node
npm install [email protected]

worked fine after forcing it to the right sass version, according to the version said to be working with the right node. 

NodeJS  Minimum node-sass version   Node Module
Node 12 4.12+   72
Node 11 4.10+   67
Node 10 4.9+    64
Node 8  4.5.3+  57

There was lots of other errors that seemed to be caused by the wrong sass version defined.

14
votes

node-gyp requires old Python 2 - link

If you don't have it installed - check other answers about installing windows-build-tools.

If you are like me and have both old and new Python versions installed, chances are that node-gyp tries to use Python 3. And that results in the following SyntaxError: invalid syntax error.

I found an article about having two Python versions installed. And they recommend renaming Python 2.* executable to python2.exe - link.

So it looks like node-gyp is expecting to find old Python 2 executable renamed. Hence the error message:

...
gyp verb check python checking for Python executable "python2" in the PATH
gyp verb `which` failed Error: not found: python2
...

Once I renamed C:\Python27\python.exe to C:\Python27\python2.exe it worked without errors.

Of course, both C:\Python27\ and C:\Python39\ have to be in PATH variable. And no need in setting old Python version in npm config. Your default Python still will be the new one.

5
votes

This is 2 years old, but none of them helped me.

I uninstalled my NodeJS v12.8.1 (Current) and installed a brand new v10.16.3 (LTS) and my ng build --prod worked.

5
votes

My answer might not apply to everyone. Node version: v10.16.0 NPM: 6.9.0

I was having a lot of trouble using node-sass and node-sass-middleware. They are interesting packages because they are widely used (millions of downloads weekly), but their githubs show a limited dependencies and coverage. I was updating an older platform I'd been working on.

What I ended up having to do was:

1) Manually Delete node_modules

2) Manually Delete package-lock.json

3) sudo npm install node-sass --unsafe-perm=true --allow-root

4) sudo npm install node-sass-middleware --unsafe-perm=true --allow-root

I had the following help, thanks!

Pre-built binaries not found for [email protected] and [email protected]

Error: EACCES: permission denied when trying to install ESLint using npm

3
votes

had the same issue lost hours trying to install different version of python on my PC. Simply Upgrade node to the latest version v8.11.2 and npm 5.6.0, then after install [email protected] and you'll be fine.

2
votes

After looking at all the answers, i notice this solution might be very helpful. It explains how to configure "npm" to find your installed python version while installing node-sass. Remember, node-sass requires node-gyp (an npm build-tool) which looks for your python path. Or just install python, and follow the same solution given (in the link). Thanks.

2
votes

Hey I got this error resolved by following the steps

  • first I uninstalled python 3.8.6 (latest version)
  • then I installed python 2.7.1 (any Python 2 version will work, but not much older and this is recommended)
  • then I added c:\python27 to environment variables
  • my OS is windows, so I followed this link
  • It worked
2
votes

I had node 15.x.x , and "node-sass": "^4.11.0". I saw in the release notes from node-sass and saw the node higest version compatible with node-sass 4.11.0 was 11, so I uninstalled node and reinstall 11.15.0 version (I'm working with Windows). Check node-sass releases. (this is what you should see in the node-sass releases.)

Hope that helps and sorry for my english :)

1
votes

I found the same issue with Node 12.19.0 and yarn 1.22.5 on Windows 10. I fixed the problem by installing latest stable python 64-bit with adding the path to Environment Variables during python installation. After python installation, I restarted my machine for env vars.

1
votes

In case of yarn projects, ignoring the node version with "yarn install --ignore-engines" will install any node-sass v. without these python errors

1
votes

Python2 maintenance status is "end of life" so it not installed by default on new ubuntu releases.

Installing the latest python2.7 worked fine for me.

Here is the instructions to install it:

tar -xf Python-2.7.18.tgz
cd Python-2.7.18
./configure --enable-optimizations
sudo make altinstall

Open a new terminal and try agin the npm install

1
votes

Here is what helped me to prevent the error Error: not found: python2 when running a project based on the old node-gyp v3.8.0.

  1. Run npm install --global --production [email protected]
  2. Rename python.exe to python2.exe in %USERPROFILE%\.windows-build-tools\python27
  3. Make sure that %USERPROFILE%\.windows-build-tools\python27 is part of your PATH environment variable (this is what windows-build-tools should already do for you)
  4. Download Visual Studio 2017 Build Tools
  5. Tell npm to use VS 2017 with npm config set msvs_version 2017
  6. Run the script which uses node-gyp (node-gyp will now find python2.exe)

Alternative: Force upgrade of node-gyp

You can also try to upgrade your project to use node-gyp v8.0.0 instead of node-gyp v3.8.0. In this case, add the following resolution entry to your package.json:

  "resolutions": {
    "node-gyp": "8.0.0"
  }

Afterwards, make sure that you have Python 3 installed and Visual Studio 2017 Build Tools and/or Visual Studio 2019 Build Tools. You can also run npm config delete msvs_version to let node-gyp automatically detect your VS version.

Tested with:

  • Windows 10 Pro Build 19042.985
  • Node.js v15.14.0
  • npm v7.7.6
  • node-gyp -v v3.8.0.
1
votes

This same issue I faced few days ago. Believe on me their is no need to install or uninstall other dependencies in your project or system.

How had I resolve this issue let me share my experience.

  • Please go to package.json file
  • Scroll down all the way below or search for optionalDependencies Object
  • Just remove this whole object & save the file
  • try npm install, it will work

Another Possible Solution:

Please check your package.json file if node-sass element is exist inside the optionalDepedencies Object then you need to run npm command in this way npm install --no-optional or also If just remove node-sass element from optionalDepedencies Object

Note: this solution is only for Angular Project

enter image description here Please Check out this screenshot of package.json file

0
votes

also you can try to use sass module instead of node-sass:

npm install sass
0
votes

If you are using Visual Studio. follow these steps:

npm cache clean --force
npm config set msvs_version 2019 --global
npm install node-sass
0
votes

We encountered this problem in 2021 when setting up a new TeamCity build agent. Originally we had installed nodejs using Chocolatey. We reinstalled going back to the original installer node-v12.12.0-x64.msi. The third screen in the installer dialog offers to install the tools necessary to compile native modules:

enter image description here

After doing this our problem was gone.