A Simple GitHub Action to Deploy .NET App to Linux

Deploying to a server can feel hard at first. This GitHub Action makes it simple. It does the same safe steps every time. You push code. The workflow handles the deploy.

Where This Workflow Lives

The file is here: .github/workflows/deploy.yml

What It Does

When the workflow runs, it does these jobs:

builds the .NET app
publishes release files
connects to Linux server using SSH
creates a backup of old files
uploads new files with rsync
restarts the app service

This saves time. It also reduces manual mistakes.

When It Runs

This workflow can run in two ways:

on push (except changes to deploy.yml)
on manual run using workflow_dispatch

So you can use auto deploy. You can also click Run when you want control.

It also uses concurrency. Only one deploy runs at a time. If a new deploy starts, the old one is cancelled.

Key YAML Snippets

These are the most important parts. You can understand the flow without reading the full file first.

Trigger + Concurrency

on:
  push:
    paths-ignore:
      - '.github/workflows/deploy.yml'
  workflow_dispatch:

concurrency:
  group: deploy-githubscrapper
  cancel-in-progress: true

Build and Publish

- name: Setup .NET
  uses: actions/setup-dotnet@v4
  with:
    dotnet-version: 8.0.x

- name: Restore
  run: dotnet restore GithubScrapper/GithubScrapper/GithubScrapper.csproj

- name: Publish
  run: dotnet publish GithubScrapper/GithubScrapper/GithubScrapper.csproj -c Release -o ./publish

Backup on Server

- name: Backup existing files on server
  run: |
    TARGET_DIR="/var/www/GithubScrapper"
    BACKUP_DIR="$TARGET_DIR/bak_$(date +%Y%m%d_%H%M%S)"
    mkdir -p "$BACKUP_DIR"

    if [ -d "$TARGET_DIR/AppFiles" ]; then
      cp -r "$TARGET_DIR/AppFiles" "$BACKUP_DIR/"
    fi

    if [ -f "$TARGET_DIR/appsettings.json" ]; then
      cp "$TARGET_DIR/appsettings.json" "$BACKUP_DIR/"
    fi

Upload and Restart

- name: Sync files to server
  run: |
    rsync -az --exclude "appsettings.json" ./publish/ user@host:/var/www/GithubScrapper/

- name: Restart service
  run: |
    sudo systemctl restart GithubScrapper
    sudo systemctl status GithubScrapper

Build Step

Before deploy, it prepares clean files.

It does this:

runs actions/checkout
installs .NET 8 with actions/setup-dotnet
restores NuGet packages
publishes release output to ./publish

Now files are ready for server upload.

SSH Setup

It uses:

webfactory/ssh-agent
SSH_PRIVATE_KEY from GitHub Secrets
ssh-keyscan to trust server host key

This keeps login secure. No password typing in CI/CD.

Safety Before Replace

Before upload, it does safety checks on server:

makes sure /var/www/GithubScrapper exists
creates backup folder with timestamp like bak_20260310_120001
copies important old files:
- AppFiles
- appsettings.json
keeps only last 5 backups

If a deploy fails, backup is there.

Upload Step

It syncs files with rsync.

source: ./publish/
target: server app folder
excludes: appsettings.json

Why exclude appsettings.json? Server config usually has real secrets and env values. It should not be overwritten.

Final Step

After upload, it does three final tasks:

sets permissions on AppFiles
restarts service with systemctl restart GithubScrapper
checks service status

So new code goes live fast.

Why This Is Useful

This workflow gives:

faster deploy
fewer manual commands
safer updates with backup
protected server config

It is simple. It is practical. It removes deploy headache.

Final Note

A good deploy workflow should be clear and safe. This one follows both. You push code. The Action does the work in order.

Full `deploy.yml` Example

If you want to try it quickly, copy the full example below.

# Deploy to Linux Server
#
# This workflow builds and deploys the GithubScrapper app to a remote Linux server via SSH and rsync.
# Each step is explained below.

name: Deploy to Linux Server

on:
  push:
    paths-ignore:
      - '.github/workflows/deploy.yml'
  workflow_dispatch:

concurrency:
  group: deploy-githubscrapper
  cancel-in-progress: true

jobs:
  deploy:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Setup .NET
        uses: actions/setup-dotnet@v4
        with:
          dotnet-version: 8.0.x

      - name: Restore
        run: dotnet restore GithubScrapper/GithubScrapper/GithubScrapper.csproj

      - name: Publish
        run: dotnet publish GithubScrapper/GithubScrapper/GithubScrapper.csproj -c Release -o ./publish

      - name: Start SSH Agent
        uses: webfactory/ssh-agent@v0.9.0
        with:
          ssh-private-key: $

      - name: Add host key
        env:
          SSH_PORT: $
        run: |
          PORT="${SSH_PORT:-22}"
          ssh-keyscan -p "$PORT" -H "$" >> ~/.ssh/known_hosts

      - name: Ensure target directory exists
        env:
          SSH_PORT: $
        run: |
          PORT="${SSH_PORT:-22}"
          ssh -p "$PORT" "$@$" "mkdir -p /var/www/GithubScrapper"

      - name: Backup existing files on server
        env:
          SSH_PORT: $
        run: |
          PORT="${SSH_PORT:-22}"
          ssh -p "$PORT" "$@$" '
            set -e
            TARGET_DIR="/var/www/GithubScrapper"
            BACKUP_DIR="$TARGET_DIR/bak_$(date +%Y%m%d_%H%M%S)"
            mkdir -p "$BACKUP_DIR"

            if [ -d "$TARGET_DIR/AppFiles" ]; then
              cp -r "$TARGET_DIR/AppFiles" "$BACKUP_DIR/"
            fi

            if [ -f "$TARGET_DIR/appsettings.json" ]; then
              cp "$TARGET_DIR/appsettings.json" "$BACKUP_DIR/"
            fi

            BACKUPS=( $(ls -dt $TARGET_DIR/bak_* 2>/dev/null) )
            if [ ${#BACKUPS[@]} -gt 5 ]; then
              for OLD in "${BACKUPS[@]:5}"; do
                rm -rf "$OLD"
              done
            fi

            if [ ! -d "$TARGET_DIR/AppFiles" ]; then
              mkdir -p "$TARGET_DIR/AppFiles"
            fi

            if [ ! -d "$TARGET_DIR/AppFiles/downloads" ]; then
              mkdir -p "$TARGET_DIR/AppFiles/downloads"
            fi

            sudo chown -R www-data:www-data /var/www/GithubScrapper/AppFiles
          '

      - name: Sync files to server
        env:
          SSH_PORT: $
        run: |
          PORT="${SSH_PORT:-22}"
          rsync -az --exclude "appsettings.json" -e "ssh -p $PORT" ./publish/ "$@$:/var/www/GithubScrapper/"

      - name: Set permissions on AppFiles directory
        env:
          SSH_PORT: $
        run: |
          PORT="${SSH_PORT:-22}"
          ssh -p "$PORT" "$@$" "chmod -R 755 /var/www/GithubScrapper/AppFiles"
          echo "Permissions set on AppFiles directory."

      - name: Restart GithubScrapper service on server
        env:
          SSH_PORT: $
        run: |
          PORT="${SSH_PORT:-22}"
          ssh -p "$PORT" "$@$" "sudo systemctl restart GithubScrapper && sudo systemctl status GithubScrapper"