wip

WoofWorkflows/Pipeline.fs

@@ -30,15 +30,15 @@ type PipelineModifier<'Agent> =
         agent + envVars + workingDir
 
 
-type AgentIsSet =
+type NewAgent =
     private
-    | AgentIsSet of image : string Comp
+    | NewAgent of image : string Comp
     override this.ToString () =
         match this with
-        | AgentIsSet comp -> "Image: " + Comp.force comp
+        | NewAgent comp -> "Image: " + Comp.force comp
 
-type AgentUnset =
-    private | AgentUnset
+type SameAgent =
+    private | SameAgent
     override this.ToString () =
         "<no image specified>"
 
@@ -47,7 +47,8 @@ type Pipeline<'Agent> =
     | ShellScript of script : string * andThen : Pipeline<'Agent>
     | ShellScriptBind of script : string * consumeStdout : (Stdout -> Pipeline<'Agent>)
     | WithModifier of Pipeline<'Agent> * PipelineModifier<'Agent>
-    | Sequence of first : Pipeline<AgentUnset> * second : Pipeline<'Agent>
+    | Sequence of first : Pipeline<SameAgent> * second : Pipeline<'Agent>
+    | ChangeAgent of first : Pipeline<NewAgent> * second : Pipeline<NewAgent>
 
 [<RequireQualifiedAccess>]
 module Pipeline =
@@ -67,11 +68,11 @@ module Pipeline =
 
 [<RequireQualifiedAccess>]
 module private PipelineModifier =
-    let empty : PipelineModifier<AgentUnset> =
+    let empty : PipelineModifier<SameAgent> =
         {
             EnvVars = []
             WorkingDir = None
-            Agent = AgentUnset
+            Agent = SameAgent
         }
 
 [<Sealed ; Class>]
@@ -88,7 +89,7 @@ type PipelineBuilder<'plat, 'agentFinal> () =
     [<CustomOperation "withEnv">]
     member _.WithEnv
         (() : unit, (key : string, value : string Comp))
-        : PipelineModifier<AgentUnset>
+        : PipelineModifier<SameAgent>
         =
         { PipelineModifier.empty with
             EnvVars = [key, value]
@@ -106,7 +107,7 @@ type PipelineBuilder<'plat, 'agentFinal> () =
     [<CustomOperation "workingDir">]
     member _.WorkingDir
         (() : unit, dir : DirectoryInfo Comp)
-        : PipelineModifier<AgentUnset>
+        : PipelineModifier<SameAgent>
         =
         { PipelineModifier.empty with
             WorkingDir = Some dir
@@ -115,26 +116,26 @@ type PipelineBuilder<'plat, 'agentFinal> () =
     [<CustomOperation "remote">]
     member _.Remote
         (() : unit, image : string Comp)
-        : PipelineModifier<AgentIsSet>
+        : PipelineModifier<NewAgent>
         =
         {
             EnvVars = []
             WorkingDir = None
-            Agent = AgentIsSet image
+            Agent = NewAgent image
         }
 
     [<CustomOperation "remote">]
     member _.Remote
-        (mods : PipelineModifier<AgentUnset>, image : string Comp)
-        : PipelineModifier<AgentIsSet>
+        (mods : PipelineModifier<SameAgent>, image : string Comp)
+        : PipelineModifier<NewAgent>
         =
         {
             EnvVars = mods.EnvVars
             WorkingDir = mods.WorkingDir
-            Agent = AgentIsSet image
+            Agent = NewAgent image
         }
 
-    member _.Return (() : unit) = Pipeline.Empty
+    member _.Return<'Agent> (() : unit) = Pipeline<'Agent>.Empty
 
     /// For running a script, capturing stdout
     member _.Bind (toRun : string, cont : Stdout -> Pipeline<'Agent>) : Pipeline<'Agent> =
@@ -142,34 +143,40 @@ type PipelineBuilder<'plat, 'agentFinal> () =
     /// For running a script, without capturing stdout
     member _.Bind (toRun : string, cont : unit -> Pipeline<'Agent>) : Pipeline<'Agent> =
         Pipeline.ShellScript (toRun, cont ())
-    /// We can bind any pipeline which doesn't say where it's going to run; the interpretation is that it'll
-    /// run wherever the parent runs.
-    member _.Bind (p : Pipeline<AgentUnset>, cont : unit -> Pipeline<'Agent>) : Pipeline<'Agent> =
+    /// We can bind any pipeline which runs on the "same agent".
+    member _.Bind (p : Pipeline<SameAgent>, cont : unit -> Pipeline<'Agent>) : Pipeline<'Agent> =
         Pipeline.Sequence (p, cont ())
-    // TODO: we could allow binding in running on the same agent as the parent, interpreting that as "run on the parent",
-    // or binding in running on a different agent from the parent, interpreting that as "run in a new agent".
-    // Seems a bit magic.
+    /// We can also bind in any pipeline to run on a different agent.
+    member _.Bind (p : Pipeline<NewAgent>, cont : unit -> Pipeline<NewAgent>) : Pipeline<'Agent> =
+        Pipeline.ChangeAgent (p, cont ())
     member _.Yield (() : unit) : unit = ()
     member _.For (expr : PipelineModifier<'Agent>, cont : unit -> Pipeline<'Agent>) : Pipeline<'Agent> =
         Pipeline.WithModifier (cont (), expr)
 
 [<AutoOpen>]
 module PipelineBuilder =
-    let pipeline<'plat, 'agent> = PipelineBuilder<'plat, 'agent> ()
+    let pipeline<'agent> = PipelineBuilder<unit, 'agent> ()
     let toStepDag<'Agent> (p : Pipeline<'Agent>) : SealedStepDag<unit, unit> = failwith $"TODO\n%s{Pipeline.toString p}"
 
     let foo () : SealedStepDag<unit, unit> =
         pipeline {
             remote (Comp.make "some-image")
-            withEnv ("hi", Comp.make "bye")
             workingDir (Comp.make (DirectoryInfo "code root here"))
             withEnv ("foo", Comp.make "bar")
+            withEnv ("hi", Comp.make "bye")
             let! (Stdout stdout) = "sh script here"
-            do! pipeline {
+            // type annotation is not necessary here but makes the location explicit
+            do! pipeline<SameAgent> {
                 withEnv ("foo", stdout)
                 do! "git config --foo"
                 return ()
             }
+            // again, type annotation is not necessary here but makes it explicit that this is running somewhere
+            // else
+            do! pipeline {
+                // remote (Comp.make "another-image")
+                return ()
+            }
             do! "a shell script"
             return ()
         }