Karma: "npm install karma" fails on windows

[BrainSlugs83]

I have the latest version of node installed:

C:\>npm -v
2.14.4

C:\>node -v
v4.1.2

I try installing karma via the docs and I get the following console output:

C:\xyz>npm install karma --save-dev

npm WARN optional dep failed, continuing [email protected]

> [email protected] install C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\bufferutil
> node-gyp rebuild


C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\bufferutil>if not defined npm_config_node_gyp (node "C:\Program Files\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node  rebuild )
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 failNoPython (C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:116:14)
gyp ERR! stack     at C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:71:11
gyp ERR! stack     at FSReqWrap.oncomplete (fs.js:82:15)
gyp ERR! System Windows_NT 10.0.10240
gyp ERR! command "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild"
gyp ERR! cwd C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\bufferutil
gyp ERR! node -v v4.1.2
gyp ERR! node-gyp -v v3.0.3
gyp ERR! not ok

> [email protected] install C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\utf-8-validate
> node-gyp rebuild


C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\utf-8-validate>if not defined npm_config_node_gyp (node "C:\Program Files\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node  rebuild )
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 failNoPython (C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:116:14)
gyp ERR! stack     at C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:71:11
gyp ERR! stack     at FSReqWrap.oncomplete (fs.js:82:15)
gyp ERR! System Windows_NT 10.0.10240
gyp ERR! command "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild"
gyp ERR! cwd C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\engine.io\node_modules\ws\node_modules\utf-8-validate
gyp ERR! node -v v4.1.2
gyp ERR! node-gyp -v v3.0.3
gyp ERR! not ok
npm WARN optional dep failed, continuing [email protected]

> [email protected] install C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\socket.io-client\node_modules\engine.io-client\node_modules\ws\node_modules\utf-8-validate
> node-gyp rebuild


C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\socket.io-client\node_modules\engine.io-client\node_modules\ws\node_modules\utf-8-validate>if not defined npm_config_node_gyp (node "C:\Program Files\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node  rebuild )
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 failNoPython (C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:116:14)
gyp ERR! stack     at C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:71:11
gyp ERR! stack     at FSReqWrap.oncomplete (fs.js:82:15)
gyp ERR! System Windows_NT 10.0.10240
gyp ERR! command "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild"
gyp ERR! cwd C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\socket.io-client\node_modules\engine.io-client\node_modules\ws\node_modules\utf-8-validate
gyp ERR! node -v v4.1.2
gyp ERR! node-gyp -v v3.0.3
gyp ERR! not ok
npm WARN optional dep failed, continuing [email protected]

> [email protected] install C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\socket.io-client\node_modules\engine.io-client\node_modules\ws\node_modules\bufferutil
> node-gyp rebuild


C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\socket.io-client\node_modules\engine.io-client\node_modules\ws\node_modules\bufferutil>if not defined npm_config_node_gyp (node "C:\Program Files\nodejs\node_modules\npm\bin\node-gyp-bin\\..\..\node_modules\node-gyp\bin\node-gyp.js" rebuild )  else (node  rebuild )
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 failNoPython (C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:116:14)
gyp ERR! stack     at C:\Program Files\nodejs\node_modules\npm\node_modules\node-gyp\lib\configure.js:71:11
gyp ERR! stack     at FSReqWrap.oncomplete (fs.js:82:15)
gyp ERR! System Windows_NT 10.0.10240
gyp ERR! command "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\node_modules\\node-gyp\\bin\\node-gyp.js" "rebuild"
gyp ERR! cwd C:\xyz\node_modules\karma\node_modules\socket.io\node_modules\socket.io-client\node_modules\engine.io-client\node_modules\ws\node_modules\bufferutil
gyp ERR! node -v v4.1.2
gyp ERR! node-gyp -v v3.0.3
gyp ERR! not ok
npm WARN optional dep failed, continuing [email protected]
npm WARN optional dep failed, continuing [email protected]
[email protected] node_modules\karma
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected]
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected])
├── [email protected] ([email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected])
├── [email protected]
├── [email protected] ([email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected])
├── [email protected] ([email protected], [email protected], [email protected], [email protected])
├── [email protected]
├── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected])
├── [email protected]
└── [email protected] ([email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected])

The first error seems to be that there is something configured wrong -- but I don't know what, since there are no steps to configure anything before running the command.

The second error I see is that python is required (there is no mention of this requirement in the docs, is this legitimate? do we really need to install python too?).

I'm guessing the rest of the errors will change once those two are figured out.

[inf3rno]

+1, same here
(why always node gyp fails by every project?! I really hate that lib)

[sateffen]

This errors are _optional dependencies_, so you can ignore them and still use karma.

The point is, that some dependencies try to use some native code, that they want to compile via node-gyp (and node-gyp requires python). But they only try, so if they fail, they fall back to another (slower) implementation.

So this is actually not a problem with karma itself, it's just the uncool presentation of npm that causes some confusion here I guess.

You do NOT need node-gyp or python for karma.

[cmacdonnacha]

I'm seeing the same error. Like @sateffen said it doesn't really matter as it goes ahead and installs the node packages anyway. However, this is a pretty crappy error, is there any way to prevent this from being displayed apart from installing Python?

[inf3rno]

I think the main problem here, that we don't know whether the installed lib is broken or not. Maybe the documentation should contain something about this, testing instructions, or something like "if you got warning, but the lib appears in node_modules, then there is nothing to worry about", etc.... I think verification would be better, because you can change the dependencies of the lib any time.

[sateffen]

But this is no problem with karma itself. I think it's strange for npm to show optional dependencies a way everyone things it's a critical error. The karma team can't do anything about it. The only thing they could do is remove the dependencies, but this would be stupid, and not helpful at all.

I guess this has to be discussed with the guys from npm (pls check if there is already an issue open, I didn't see one.

[egoroof]

I've got the same error. windows10 node5.1 npm3.3.12
But karma works fine!

[katlimruiz]

This should be in the readme! I was banging my head debating over to install python in Windows, doing so, and still node-gyp failing :angry:
Let's see how it goes

[GiampaLab]

The easiest thing to do is to run npm without optional dependencies so that you won't need to install python and a stand alone c++ compiler on each box and you won't get nasty errors displayed.

npm install karma --no-optional

[FourLeafClover]

How to fix this error. help,help

[rayfoss]

@FourLeafClover karma/chokidar depends on fsevents, which breaks on every node update and system update. If you use karma, don't use node latest and wait 2 years for os updates and always use a Mac. Do you happen to be using Webpack 2? If so, that's probably the issue... update that.

[devoto13]

I believe this has been fixed in the meantime. Please open a new issue including a minimal reproduction if you still experience this problem.