Run conditions

Reusable run conditions implement IRunCondition:

Run conditions may be evaluated both during execution and by PlanAsync() or --dry-run. Keep them side-effect-free: they must not mutate external state or rely on being evaluated exactly once. Fluent conditions that await module results are reported as unknown in a dry-run plan because planning never executes dependencies to produce those results.

public class ServiceIsAvailable : IRunCondition
{
    public async Task<bool> EvaluateAsync(IPipelineContext context)
    {
        var response = await context.Http.SendAsync("https://www.example.com/ping");
        return response.StatusCode == HttpStatusCode.OK;
    }
}

Apply the condition with an attribute that states its intent:

[RunIfAll<ServiceIsAvailable>]
public class DeployModule : Module

• [SkipIf<T1, ..., T4>] skips when any condition is true.
• [RunIfAll<T1, ..., T4>] runs only when every condition is true.
• [RunIfAny<T1, ..., T4>] runs when at least one condition is true.

When a condition needs constructor state, derive an attribute from SkipIfAttribute, RunIfAllAttribute, or RunIfAnyAttribute:

public sealed class RunIfRegionAttribute(string region) : RunIfAllAttribute
{
    public override Task<bool> EvaluateAsync(IPipelineContext context) =>
        Task.FromResult(
            context.Environment.Variables.GetEnvironmentVariable("REGION") == region);
}

[RunIfRegion("eu-west-2")]
public class RegionalDeployModule : Module<None>

The base class also provides a cancellation-aware overload. Override it when the condition performs cancellable asynchronous work.

Multiple condition attributes are evaluated in this order: SkipIf, RunIfAll, then RunIfAny. Attribute conditions and fluent .WithSkipWhen(...) conditions run in the same execution pipeline after dependency waiting. Both invoke skipped hooks and lifecycle notifications.

Fluent dependencies are validated before execution conditions are evaluated. Every dependency declared with DependsOn<T>() must therefore be registered, even when an attribute condition will skip the consuming module on the current platform or environment.

Built-in platform conditions include OnLinux, OnWindows, and OnMacOS:

[RunIfAll<OnLinux>]
public class LinuxModule : Module

Parameterized built-ins cover environment variables and operating systems:

[RunIfEnvironmentVariable("NUGET_API_KEY")]
[SkipIfEnvironmentVariable("CI", "true")]
[RunIfOperatingSystem(OperatingSystemIdentifier.Linux, OperatingSystemIdentifier.MacOS)]
public class PublishModule : Module<None>

Use RunIfEnvironmentVariableUnset or SkipIfEnvironmentVariableUnset for the inverse environment-variable check. The ModularPipelines.Git package also provides RunIfBranch, RunIfBranchStartsWith, and SkipIfBranch; these stateful attributes use the same base classes.

One-off conditions can use Configure().WithSkipWhen(...).