Warning: The StrongLoop slc tool is still available, however it is not
recommended for LoopBack development, as it will be deprecated in the future. To upgrade an
existing installation to the latest version, see Updating to the latest version.
Why do I need to install a compiler?
Some devops features such as monitoring and memory / CPU profiling require native (C++) code. StrongLoop distributes its software with npm, but npm compiles native code upon installation. Therefore, to take advantage of these features, you must install a compiler. If you don’t want these features, you may see error messages, but you should still be able install successfully.
Page Contents
Overview
If you don’t have a C++ compiler (Visual C++ on Windows or XCode on OSX) and associated command-line tools, you won’t be able to view most useful metrics, and you won’t be able to perform CPU profiling or take heap snapshots.
Important: If you don’t have compiler tools, when you run your application, you may see error messages such as “strong-agent could not load optional native add-on”.
To eliminate the error messages and enable monitoring and tracing features, install the appropriate C++ compiler and related tools as described below.
Configuring Python directory
Npm uses node-gyp to compile native modules, and node-gyp requires Python. If you installed Python in a non-standard directory, run this command to configure your setup:
$ npm config set python /path/to/python
where /path/to/python is the directory where Python is installed.
For more information, see the node-gyp documentation.
Windows
Install windows-build-tools:
C:\> npm install --global --production windows-build-tools
This downloads Python 2.7.x and and Visual C++ Build Tools 2015. These tools are required to compile popular native modules. It will also configure your machine and npm appropriately. Both installations are conflict-free, meaning that they do not mess with existing installations of Visual Studio, C++ Build Tools, or Python.
MacOS
Install:
- Apple Xcode.
- Depending on your version of MacOS and Xcode, you may need to also install the command-line tools. To install them in Xcode:
- Click Xcode > Preferences.
- Choose Downloads.
- Click the install button next to “Command-line Tools”.
Most versions of OSX come with Python by default. If for some reason you don’t have it, download and install Python.
Xcode license issues
If you see errors such as:
Agreeing to the Xcode/iOS license requires admin privileges, please re-run as root via sudo.
Then you recently upgraded or installed Xcode and haven’t agreed to the license yet.
Enter the following command to validate your Xcode license, then reinstall StrongLoop:
$ sudo xcode-select
Linux
Many Linux systems come with the necessary tools. The specific requirements are:
- Python (v2.7 recommended; v3.x.x is not supported). If you installed Python in a non-standard location, see Configuring Python directory.
make- A proper C/C++ compiler toolchain, like GCC. NOTE: g– version 4.2 or later is required.
On Debian and Debian-derived distributions (Ubuntu, Mint, and so on), use the command:
$ apt-get install build-essential
Adding swap space
If during installation, you see the error message:
virtual memory exhausted: Cannot allocate memory
Then you need to add swap space so the compiler will have enough RAM. For example:
$ dd if=/dev/zero of=/swap bs=1M count=1024
$ mkswap /swap
$ swapon /swap
After entering these commands, reinstall StrongLoop.
Note that the above command does not make the change permanent. When you reboot, you’ll need to re-run the swapon /swap command if you want to reinstall or if your application uses binary add-ons.
For more information, see How To Configure Virtual Memory (Swap File) on a VPS.