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DSL example (#122)
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‎README.md‎

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@@ -21,6 +21,7 @@ Prerequisites:
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* [ContextPropagation](src/ContextPropagation) - Context propagation via interceptors.
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* [CounterInterceptor](src/CounterInterceptor/) - Simple Workflow and Client Interceptors example.
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* [DependencyInjection](src/DependencyInjection) - How to inject dependencies in activities and use generic hosts for workers
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* [Dsl](src/Dsl) - Workflow that interprets and executes workflow steps from a YAML-based DSL.
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* [EagerWorkflowStart](src/EagerWorkflowStart) - Demonstrates usage of Eager Workflow Start to reduce latency for workflows that start with a local activity.
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* [Encryption](src/Encryption) - End-to-end encryption with Temporal payload codecs.
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* [EnvConfig](src/EnvConfig) - Load client configuration from TOML files with programmatic overrides

‎TemporalioSamples.sln‎

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@@ -101,6 +101,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TemporalioSamples.Timer", "
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EndProject
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TemporalioSamples.UpdatableTimer", "src\UpdatableTimer\TemporalioSamples.UpdatableTimer.csproj", "{5D02DFEA-DC08-4B7B-8E26-EDAC1942D347}"
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EndProject
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "TemporalioSamples.Dsl", "src\Dsl\TemporalioSamples.Dsl.csproj", "{AF077751-E4B9-4696-93CB-74653F0BB6C4}"
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EndProject
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Global
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GlobalSection(SolutionConfigurationPlatforms) = preSolution
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Debug|Any CPU = Debug|Any CPU
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{5D02DFEA-DC08-4B7B-8E26-EDAC1942D347}.Release|x64.Build.0 = Release|Any CPU
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{5D02DFEA-DC08-4B7B-8E26-EDAC1942D347}.Release|x86.ActiveCfg = Release|Any CPU
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{5D02DFEA-DC08-4B7B-8E26-EDAC1942D347}.Release|x86.Build.0 = Release|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Debug|Any CPU.Build.0 = Debug|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Debug|x64.ActiveCfg = Debug|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Debug|x64.Build.0 = Debug|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Debug|x86.ActiveCfg = Debug|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Debug|x86.Build.0 = Debug|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Release|Any CPU.ActiveCfg = Release|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Release|Any CPU.Build.0 = Release|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Release|x64.ActiveCfg = Release|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Release|x64.Build.0 = Release|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Release|x86.ActiveCfg = Release|Any CPU
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{AF077751-E4B9-4696-93CB-74653F0BB6C4}.Release|x86.Build.0 = Release|Any CPU
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EndGlobalSection
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GlobalSection(SolutionProperties) = preSolution
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HideSolutionNode = FALSE
@@ -653,5 +667,6 @@ Global
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{52CE80AF-09C3-4209-8A21-6CFFAA3B2B01} = {1A647B41-53D0-4638-AE5A-6630BAAE45FC}
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{B37B3E98-4B04-48B8-9017-F0EDEDC7BD98} = {1A647B41-53D0-4638-AE5A-6630BAAE45FC}
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{5D02DFEA-DC08-4B7B-8E26-EDAC1942D347} = {1A647B41-53D0-4638-AE5A-6630BAAE45FC}
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{AF077751-E4B9-4696-93CB-74653F0BB6C4} = {1A647B41-53D0-4638-AE5A-6630BAAE45FC}
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EndGlobalSection
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EndGlobal

‎src/Dsl/DslActivities.cs‎

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namespace TemporalioSamples.Dsl;
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using Microsoft.Extensions.Logging;
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using Temporalio.Activities;
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public static class DslActivities
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{
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[Activity("activity1")]
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public static string Activity1(string arg)
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{
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ActivityExecutionContext.Current.Logger.LogInformation("Executing activity1 with arg: {Arg}", arg);
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return $"[result from activity1: {arg}]";
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}
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[Activity("activity2")]
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public static string Activity2(string arg)
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{
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ActivityExecutionContext.Current.Logger.LogInformation("Executing activity2 with arg: {Arg}", arg);
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return $"[result from activity2: {arg}]";
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}
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[Activity("activity3")]
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public static string Activity3(string arg1, string arg2)
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{
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ActivityExecutionContext.Current.Logger.LogInformation("Executing activity3 with args: {Arg1} and {Arg2}", arg1, arg2);
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return $"[result from activity3: {arg1} {arg2}]";
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}
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[Activity("activity4")]
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public static string Activity4(string arg)
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{
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ActivityExecutionContext.Current.Logger.LogInformation("Executing activity4 with arg: {Arg}", arg);
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return $"[result from activity4: {arg}]";
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}
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[Activity("activity5")]
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public static string Activity5(string arg1, string arg2)
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{
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ActivityExecutionContext.Current.Logger.LogInformation("Executing activity5 with args: {Arg1} and {Arg2}", arg1, arg2);
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return $"[result from activity5: {arg1} {arg2}]";
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}
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}

‎src/Dsl/DslInput.cs‎

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using System.Text.Json.Serialization;
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using YamlDotNet.Serialization;
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namespace TemporalioSamples.Dsl;
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public record DslInput
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{
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public record ActivityInvocation
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{
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required public string Name { get; init; }
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public IReadOnlyList<string> Arguments { get; init; } = Array.Empty<string>();
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public string? Result { get; init; }
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}
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[JsonPolymorphic(TypeDiscriminatorPropertyName = "statementType")]
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[JsonDerivedType(typeof(ActivityStatement), "activity")]
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[JsonDerivedType(typeof(SequenceStatement), "sequence")]
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[JsonDerivedType(typeof(ParallelStatement), "parallel")]
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public abstract record Statement;
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public record ActivityStatement : Statement
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{
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required public ActivityInvocation Activity { get; init; }
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}
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public record Sequence
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{
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required public IReadOnlyList<Statement> Elements { get; init; }
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}
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public record SequenceStatement : Statement
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{
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required public Sequence Sequence { get; init; }
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}
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public record ParallelBranches
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{
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required public IReadOnlyList<Statement> Branches { get; init; }
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}
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public record ParallelStatement : Statement
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{
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required public ParallelBranches Parallel { get; init; }
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}
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required public Statement Root { get; init; }
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public Dictionary<string, object> Variables { get; init; } = new();
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public static DslInput Parse(string yamlContent)
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{
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var deserializer = new DeserializerBuilder().Build();
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var yamlObject = deserializer.Deserialize<Dictionary<string, object>>(yamlContent)
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?? throw new InvalidOperationException("Failed to parse YAML");
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return ConvertToDslInput(yamlObject);
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}
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private static DslInput ConvertToDslInput(Dictionary<string, object> yaml)
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{
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var variables = new Dictionary<string, object>();
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if (yaml.TryGetValue("variables", out var varsObj) && varsObj is Dictionary<object, object> varsDict)
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{
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foreach (var kvp in varsDict)
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{
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variables[kvp.Key.ToString() ?? string.Empty] = kvp.Value;
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}
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}
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var rootObj = yaml["root"];
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var root = ConvertToStatement(rootObj);
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return new DslInput { Root = root, Variables = variables };
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}
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private static Statement ConvertToStatement(object obj)
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{
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if (obj is not Dictionary<object, object> dict)
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{
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throw new ArgumentException("Statement must be a dictionary");
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}
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if (dict.TryGetValue("activity", out var activityObj))
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{
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return new ActivityStatement { Activity = ConvertToActivityInvocation(activityObj) };
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}
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if (dict.TryGetValue("sequence", out var sequenceObj))
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{
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var seqDict = (Dictionary<object, object>)sequenceObj;
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var elements = ((List<object>)seqDict["elements"])
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.Select(ConvertToStatement)
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.ToList();
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return new SequenceStatement { Sequence = new Sequence { Elements = elements } };
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}
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if (dict.TryGetValue("parallel", out var parallelObj))
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{
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var parDict = (Dictionary<object, object>)parallelObj;
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var branches = ((List<object>)parDict["branches"])
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.Select(ConvertToStatement)
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.ToList();
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return new ParallelStatement { Parallel = new ParallelBranches { Branches = branches } };
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}
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throw new ArgumentException("Unknown statement type");
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}
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private static ActivityInvocation ConvertToActivityInvocation(object obj)
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{
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var dict = (Dictionary<object, object>)obj;
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var name = dict["name"].ToString() ?? throw new ArgumentException("Activity name is required");
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var arguments = new List<string>();
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if (dict.TryGetValue("arguments", out var argsObj) && argsObj is List<object> argsList)
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{
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arguments = argsList.Select(a => a.ToString() ?? string.Empty).ToList();
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}
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string? result = null;
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if (dict.TryGetValue("result", out var resultObj))
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{
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result = resultObj.ToString();
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}
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return new ActivityInvocation
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{
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Name = name,
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Arguments = arguments,
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Result = result,
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};
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}
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}

‎src/Dsl/DslWorkflow.workflow.cs‎

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namespace TemporalioSamples.Dsl;
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using Microsoft.Extensions.Logging;
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using Temporalio.Workflows;
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[Workflow]
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public class DslWorkflow
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{
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private readonly Dictionary<string, object> variables;
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[WorkflowInit]
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public DslWorkflow(DslInput input) => variables = input.Variables;
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[WorkflowRun]
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public async Task<Dictionary<string, object>> RunAsync(DslInput input)
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{
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Workflow.Logger.LogInformation("Running DSL workflow");
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await ExecuteStatementAsync(input.Root);
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Workflow.Logger.LogInformation("DSL workflow completed");
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return variables;
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}
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private async Task ExecuteStatementAsync(DslInput.Statement statement)
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{
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switch (statement)
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{
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case DslInput.ActivityStatement stmt:
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// Invoke activity loading arguments from variables and optionally storing result as a variable
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var result = await Workflow.ExecuteActivityAsync<object>(
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stmt.Activity.Name,
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stmt.Activity.Arguments.Select(arg => variables[arg]).ToArray(),
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new ActivityOptions { StartToCloseTimeout = TimeSpan.FromMinutes(1) });
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if (!string.IsNullOrEmpty(stmt.Activity.Result))
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{
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variables[stmt.Activity.Result] = result;
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}
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break;
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case DslInput.SequenceStatement stmt:
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foreach (var element in stmt.Sequence.Elements)
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{
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await ExecuteStatementAsync(element);
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}
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break;
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case DslInput.ParallelStatement stmt:
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await Workflow.WhenAllAsync(stmt.Parallel.Branches.Select(ExecuteStatementAsync));
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break;
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default:
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throw new InvalidOperationException($"Unknown statement type: {statement.GetType().Name}");
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}
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}
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}

‎src/Dsl/Program.cs‎

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using Microsoft.Extensions.Logging;
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using Temporalio.Client;
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using Temporalio.Client.EnvConfig;
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using Temporalio.Worker;
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using TemporalioSamples.Dsl;
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// Create a client to localhost on default namespace
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var connectOptions = ClientEnvConfig.LoadClientConnectOptions();
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if (string.IsNullOrEmpty(connectOptions.TargetHost))
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{
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connectOptions.TargetHost = "localhost:7233";
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}
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connectOptions.LoggerFactory = LoggerFactory.Create(builder =>
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builder.
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AddSimpleConsole(options => options.TimestampFormat = "[HH:mm:ss] ").
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SetMinimumLevel(LogLevel.Information));
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var client = await TemporalClient.ConnectAsync(connectOptions);
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async Task RunWorkerAsync()
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{
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// Cancellation token cancelled on ctrl+c
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using var tokenSource = new CancellationTokenSource();
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Console.CancelKeyPress += (_, eventArgs) =>
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{
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tokenSource.Cancel();
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eventArgs.Cancel = true;
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};
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// Run worker until cancelled
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Console.WriteLine("Running worker");
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using var worker = new TemporalWorker(
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client,
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new TemporalWorkerOptions(taskQueue: "dsl-sample")
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.AddAllActivities(typeof(DslActivities), null)
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.AddWorkflow<DslWorkflow>());
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try
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{
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await worker.ExecuteAsync(tokenSource.Token);
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}
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catch (OperationCanceledException)
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{
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Console.WriteLine("Worker cancelled");
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}
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}
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async Task ExecuteWorkflowAsync(string yamlFile)
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{
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var yamlContent = await File.ReadAllTextAsync(yamlFile);
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var dslInput = DslInput.Parse(yamlContent);
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Console.WriteLine($"Executing workflow from {yamlFile}");
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var result = await client.ExecuteWorkflowAsync(
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(DslWorkflow wf) => wf.RunAsync(dslInput),
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new(id: $"dsl-workflow-{Guid.NewGuid()}", taskQueue: "dsl-sample"));
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Console.WriteLine("Workflow completed. Final variables:");
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foreach (var kvp in result)
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{
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Console.WriteLine($" {kvp.Key}: {kvp.Value}");
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}
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}
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switch (args.ElementAtOrDefault(0))
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{
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case "worker":
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await RunWorkerAsync();
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break;
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case "workflow":
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var yamlFile = args.ElementAtOrDefault(1)
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?? throw new ArgumentException("Must provide YAML file path as second argument");
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await ExecuteWorkflowAsync(yamlFile);
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break;
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default:
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throw new ArgumentException("Must pass 'worker' or 'workflow' as the first argument");
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}

‎src/Dsl/README.md‎

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# DSL
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This sample demonstrates a Temporal workflow that interprets and executes arbitrary workflow steps defined in a
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YAML-based Domain Specific Language (DSL).
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To run, first see [README.md](../../README.md) for prerequisites. Then, run the following from this directory
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in a separate terminal to start the worker:
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dotnet run worker
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Then in another terminal, run a workflow from this directory:
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dotnet run workflow workflow1.yaml
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Or run the more complex parallel workflow:
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dotnet run workflow workflow2.yaml
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The worker terminal will show logs of activities being executed, and the workflow terminal will display the final
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variables after the workflow completes.

‎src/Dsl/TemporalioSamples.Dsl.csproj‎

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<OutputType>Exe</OutputType>
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</PropertyGroup>
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<ItemGroup>
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<PackageReference Include="YamlDotNet" Version="16.2.0" />
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</ItemGroup>
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<ItemGroup>
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<None Update="workflow1.yaml">
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<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
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</None>
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<None Update="workflow2.yaml">
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<CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
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</None>
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</ItemGroup>
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</Project>

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