20. May 2021

Xcode: How to quickly filter only errors from the build

The best software practice tells you that you should not have build warnings in the projects. It’s easier to spot a potential problem.

Sometimes it’s necessary to import larger portion of code which generates many warnings and it’s very hard to find the error which blocks compilation of iOS or macOS application in Xcode.

The quick way to filter out warnings and see only errors in Xcode is to click X icon at the bottom of Issue Navigator with the title “Show only errors”:

20. April 2021

How to statically link Rust application for Windows

Rust compiler can generate a single binary that contains all dependencies. This is a great feature for creating stand-alone tools or tools for containers.

There is one gotcha for Windows which does not appear on a developer’s machine. When you move the application to a brand new installation of Windows or you try to start the in Windows Docker Container which contains Windows for Datacenters the app won’t start.

Why? The system is missing Microsoft Visual C++ Redistributable 2015-2019 (vc_redist) which you can download from microsoft.com.

It’s quite inconvenient to force the user to install the package in the case of a stand-alone Rust tool. The package installation even requires elevation of privileges.

The alternative approach to distributing vc_redist is to statically link CRT library into the application. It will result in a slightly bigger application around +100KB.

It’s necessary to tell rustc to perform static linking of CRT.

In the project create file .cargo/config.toml:

[target.x86_64-pc-windows-msvc]
rustflags = ["-C", "target-feature=+crt-static"]

Rebuild the application and the new binary is statically linked and can run even on Windows 8 without vc_redist.

The interesting part is how to determine the proper target name which is on the first line of the example configuration. Many examples on the internet are referring to target.i686-pc-windows-msvc which does not work. Use the following command to determine parts of the name of the target:

rustc --print cfg
target_arch="x86_64"
target_endian="little"
target_env="msvc"
target_family="windows"
target_feature="fxsr"
target_feature="sse"
target_feature="sse2"
target_os="windows"
target_pointer_width="64"
target_vendor="pc"
windows

The target name is composed of values on the lines above.

5. December 2019

Helm 3.x fails with Error: must either provide a name or specify –generate-name

If you follow tutorials on using Helm, it might happen that they’re outdated, because they’re targeting Helm 2.x.

Following command for install will fail with error:

helm install -n aks-georgik-rocks aks-georgik-rocks-chart
Error: must either provide a name or specify --generate-name

The fix is simple. The syntax for helm 3.x is following:

helm install [NAME] [CHART] [flags]

Just remove -n. The command will look like this:

helm install aks-georgik-rocks aks-georgik-rocks-chart

19. September 2019

Xamarin Visual Studio – Error ADB0020 Android ABI mismatch

Following error message might pop-up when you to run Xamarin app on Android:

Error ADB0020: Android ABI mismatch. You are deploying an app supporting ‘armeabi-v7a’ ABIs to an incompatible device of ABI ‘x86’. You should either create an emulator matching one of your app’s ABIs or add ‘x86’ to the list of ABIs your app builds for.

Here is how you can resolve it.

In Solution Explorer select your project.

Right-click and select Properties or press Alt+Enter.

Select Android Options, scroll down. In right bottom corner click Advanced button.

From the drop down menu select desired architecture, e.g. x86_x64.

Note: After changing any checkbox it is necessary to wait a bit so that Visual Studio syncs the preferences.

Now you should be able to run the project.

24. July 2019

Creating Python virtualenv fails with error: Could not find a suitable TLS CA

You can create Python virtualenv using command:

virtualenv -p /usr/bin/python3 py-env3

You may encounter following strange error:

  Collecting setuptools
Exception:
Traceback (most recent call last):
  File "/usr/share/python-wheels
...
OSError: Could not find a suitable TLS CA certificate bundle, invalid path: /etc/ssl/certs/ca-certificates.crt
...
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 145, in apport_excepthook
    os.O_WRONLY | os.O_CREAT | os.O_EXCL, 0o640), 'wb') as f:
FileNotFoundError: [Errno 2] No such file or directory: '/var/crash/_usr_bin_virtualenv.1000.crash'

The error message is not very clear. Problem is caused by ca-certificates and it could be fixed by command:

sudo update-ca-certificates