DdnsUpdate.NET

Building the single-file DdnsUpdate.exe

How to produce the one-file DdnsUpdate.exe that runs in production, and how to deploy it.

What this tree is

This line descends from v0.1.0 (tag e2252fd, 2024-02-23), the version production runs, and is now version 0.2.0 (see CHANGELOG.md). Settings files sit flat beside the executable. There is no config subfolder anywhere in this line, and the code has no concept of one: Program.cs sets the current directory to the executable directory and reads .\appsettings.*.json from there. Version 0.2.0 reads the same settings files as 0.1.0, so upgrading means replacing only DdnsUpdate.exe.

Do not confuse this with the master line in the same GitHub repository. That is an unrelated history with no common ancestor, it reads settings from a config subfolder, and it names its executable ddnsupdate.exe in lowercase. It also reports version 0.1.0, so a 0.1.0 build cannot be told apart by its version string. Use the settings location or the executable name casing instead.

Prerequisites

.NET SDK 10.0 (pinned by global.json, which allows any later 10.0 feature band). The libraries target net10.0 and the executable targets net10.0-windows10.0.17763.0. All packages resolve from nuget.org, with versions managed centrally in Directory.Packages.props.

Build

Open DdnsUpdate.slnx (repository root) in Visual Studio, or from the repository root:

dotnet build
dotnet test
dotnet publish src\DdnsUpdate.Application -p:PublishProfile=win-x64-single

The win-x64-single publish profile (src\DdnsUpdate.Application\Properties\PublishProfiles\win-x64-single.pubxml) sets Release, win-x64, self-contained, single file, and the publish output folder at the repository root. It is equivalent to:

dotnet publish src\DdnsUpdate.Application\DdnsUpdate.Application.csproj `
  -c Release `
  -r win-x64 `
  --self-contained true `
  -p:PublishSingleFile=true `
  -p:IncludeNativeLibrariesForSelfExtract=true `
  -o publish

DdnsUpdate.Application.csproj sets <AssemblyName>DdnsUpdate</AssemblyName>, so the published file is DdnsUpdate.exe.

Single file is required, not optional. FilePathHelper notes that Assembly.GetExecutingAssembly().Location returns an empty string in a bundled assembly, and works around it with AppDomain.CurrentDomain.BaseDirectory. That workaround assumes a bundled publish.

Do not build from a deeply nested directory. Windows still limits paths to 260 characters by default, and project references fail past that with a misleading MSB9008 warning claiming the referenced project does not exist.

Self-contained or framework-dependent

Option Command change Result
Self-contained as written above About 100 MB. Runs with no .NET runtime installed.
Framework-dependent add --self-contained false (or edit the profile) A few MB. Requires the .NET 10 runtime on the target machine.

Check the size of the executable already in production to see which was used last time. Either works.

Publish output

publish/
    DdnsUpdate.exe
    appsettings.json
    appsettings.production.json
    *.pdb

Flat, with no subfolders. The .pdb files are debug symbols and can be deleted from a deployment.

appsettings.production.user.json is deliberately absent. It holds credentials and the per-domain Cloudflare zone and record IDs, it is excluded by .gitignore, and it lives only on the server. Deploying never overwrites it.

The publish folder is covered by .gitignore at any depth, so build output is never committed.

Deploying to a Windows server

  1. Stop the running updater first. It runs on a timed loop, so a live process holds the executable and the copy will fail or leave a mixed set of files.
  2. Back up the whole application directory, including the settings files.
  3. Copy DdnsUpdate.exe over the existing one.
  4. Leave appsettings.production.user.json in place. Do not move anything into a config folder; this version does not look there.
  5. Restart the updater and confirm it reports the expected domain count.

Verifying a deployment

A normal run proves very little. The updater only calls Cloudflare when the detected public IP address differs from the stored one, so with an unchanged address it skips every domain.

To force real API calls, temporarily set alwaysUpdateDdnsEvenIfUnchanged to true under applicationSettings.ddnsSettings, run once, confirm every domain reports success, then set it back to false.

The process exit code is 0 when a run finishes normally, including stopping after maximumDdnsUpdateIterations, and 1 when startup fails (for example an invalid ipAddressProviders URL) or the update loop throws. A Windows Service that exits with 1 triggers its configured recovery actions.

For Cloudflare-proxied records, confirm afterwards that the orange cloud is still on. This version sends a PATCH so that omitted fields such as proxied are preserved. A PUT would reset them and silently disable the proxy, which is the bug this build fixes.

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