Adding yarn install path to %PATH%

[Tehnix]

For some reason, out of nowhere App Services stopped finding my npm executables, meaning that yarn could not be located.

The error will manifest itself something like,

...
remote: Verifying Yarn Install.
remote: D:\local\AppData\npm\yarn -> D:\local\AppData\npm\node_modules\yarn\bin\yarn.js
remote: D:\local\AppData\npm\yarnpkg -> D:\local\AppData\npm\node_modules\yarn\bin\yarn.js
remote: + yarn@1.6.0
remote: updated 1 package in 2.114s
remote: Installing Yarn Packages.
remote: yarn install v1.6.0
remote: [1/5] Validating package.json...
remote: [2/5] Resolving packages...
remote: success Already up-to-date.
remote: $ yarn run build
remote: 'yarn' is not recognized as an internal or external command,
remote: operable program or batch file.
remote: info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
remote: error Command failed with exit code 1.
remote: Failed exitCode=1, command=D:\local\AppData\npm\yarn install --production
remote: An error has occurred during web site deployment.
remote:
remote: Error - Changes committed to remote repository but deployment to website failed.
To https://xxxxxx.scm.azurewebsites.net:443/xxxxxx.git
   d7de8b7..8d52910  master -> master

My fix was to add the path to NPM executables to the batch PATH environmental variable.

SET PATH=%PATH%;D:\local\AppData\npm

so it now looks like this,

:: 3. Install Yarn
echo Verifying Yarn Install.
call :ExecuteCmd !NPM_CMD! install yarn -g
SET PATH=%PATH%;D:\local\AppData\npm

:: 4. Install Yarn packages
echo Installing Yarn Packages.
IF EXIST "%DEPLOYMENT_TARGET%\package.json" (
  pushd "%DEPLOYMENT_TARGET%"
  call :ExecuteCmd yarn install --production
  IF !ERRORLEVEL! NEQ 0 goto error
  popd
)

I don't know if other's are experiencing this issue, but if they are, I hope this leads them here. I am not 100% sure if the path will stay the same in every scenario, or it needs to be set in a more dynamic way, else you should be able to use this small addition in these scripts.

[aweber1]

I ran into this same problem yesterday. Unfortunately didn't see this issue in the repo or could've saved myself a few hours of troubleshooting :)

Anyways, came to the same conclusion that the PATH should also be set. I used the following snippet to set it in a more "dynamic" way:

FOR /F "tokens=* USEBACKQ" %%F IN (`npm config get prefix`) DO (
SET "PATH=%PATH%;%%F"
)

Basically, it calls npm config get prefix which should report the install location for npm packages. Then store that value in the PATH variable.

Final version:

:: 3. Install Yarn
echo Verifying Yarn Install.
call :ExecuteCmd !NPM_CMD! install yarn -g
FOR /F "tokens=* USEBACKQ" %%F IN (`npm config get prefix`) DO (
SET "PATH=%PATH%;%%F"
)
IF !ERRORLEVEL! NEQ 0 goto error```

[tony-gutierrez]

Does this not result in the PATH constantly being made longer?