Hello,
when building with .NET Core using multiple steps, Travis-CI reinstalls the .NET Core sdk every time.
Secondly it does seem to ignore the flags DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1 and DOTNET_CLI_TELEMETRY_OPTOUT=1.
There was originally an issue on github that has been closed but I didn’t seem to find it here.
Any help would be very much appreciated since this is causing the build time to be quite long.
Kind regards,
Sami
Hello,
I’ve seen the same issue.
First build on travis, 2min just for a dotnet build… it’s pretty long! 
As we’re not able to add env var for the installation, we even can’t test or workaround it.
Or, well, we can workaround it by pulling mcr.microsoft.com/dotnet/core/sdk:2.2-alpine docker image and running scripts in it, but I don’t know if it’s as easy to do with Travis as in Gitlab CI.
Ayust
Yeah I thought about that too but I’d prefer not to do so. I can live with the build-time, just thought there might be a way to improve it that I don’t know of (yet).
Kind regards,
Sami
Travis-CI spins up a fresh virtual machine on every build, so we have to re-install .Net Core every time.
Short of pre-installing C# on the virtual machine image, which isn’t possible right now (Travis-CI tries to minimize the amount of software preinstalled on the image), I don’t think there’s much we can do.
My guess is that sudo is not preserving the exported variables set on lines 131 and 134.
It looks like it should be a simple fix, but I don’t have the time to set up a build environment to fix and test it.
Well, the alpha Windows builds have some of this pre-installed already. Might be useful … 
Would you elaborate how you would fix it? Maybe I could try it myself doing so and creating a PR.
Oh no… please no windows 
The straightforward solution would be to set the environment variable directly in the command that needs it (and the exports wouldn’t be needed). Line 152:
sh.cmd "sudo DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1 DOTNET_CLI_TELEMETRY_OPTOUT=1 apt-get install -qq dotnet-#{dotnet_package_prefix}-#{dotnet_package_version}", timing: true, assert: true
The other solution would be to update the sudoers file with env_keep options for the required variables. Without trying it, I’m not sure whether that would work, because it might require the user session to log out to apply sudoers changes.
I haven’t tested it, but here’s the first proposed solution as a commit: https://github.com/joel0/travis-build/commit/bd6465c14d877561fafab42062c6c676481c90ed If someone can test it, I can submit a PR if wanted. In theory, it should work as desired.
cc @joshua-anderson Thoughts on this change to speed up the install/setup of .net?
I haven’t been able to build FluentMigrator CI pull requests on GitHub due to the enormous increase in build time.
Would it be faster to use Docker and just install docker-ce via apt and pull down the dotnet sdk image form the Docker Registry than build mono from scratch?
I had the need to use .NET-Core preview and found this post
Using snap is some what faster. Snap is installed once but for each step dotnet is installed. For releases I am saving around two minutes.
Here a sample with multiple steps
sudo: required
dist: bionic
language: csharp
solution: Etdb.ServiceBase.AspNetCore.sln
mono: none
addons:
snaps:
- name: dotnet-sdk
classic: true
channel: latest/beta
stages:
- build
- test
- publish
jobs:
include:
- stage: build
name: build solution
before_script:
- sudo snap alias dotnet-sdk.dotnet dotnet
script: dotnet restore && dotnet build
- stage: test
name: run-tests
services: mongodb
before_script:
- sudo snap alias dotnet-sdk.dotnet dotnet
- sh install_link_libgdiplus.sh
- sh setup-mongodb-user.sh "$MONGODB_USERNAME" "$MONGODB_PASSWORD"
script: ./run-tests.sh
- stage: publish
name: publish-packages
if: tag IS present
before_script:
- sudo snap alias dotnet-sdk.dotnet dotnet
script: ./publish-packages.sh "$NUGET_SOURCE" "$ETDB_NUGET_APIKEY" "$TRAVIS_TAG"