feat: enable scaffolding for host builds

- Refactors out scaffolding to its own package
- Adds additional scaffolding tests
- Replaces the mock scaffolded functoin with actual code
- Fixes a bug where local jobs were not receiving context cancellation
- Fixes a bug where signatures of instanced HTTP was erroring
- Adds a sleep/wait for tcp listener when starting host jobs

pkg/functions/client.go

@@ -17,6 +17,8 @@ import (
 	"time"
 
 	"gopkg.in/yaml.v2"
+
+	"knative.dev/func/pkg/scaffolding"
 	"knative.dev/func/pkg/utils"
 )
 
@@ -414,10 +416,10 @@ func (c *Client) Runtimes() ([]string, error) {
 // create a running function whose source code and metadata match that provided
 // by the passed function instance, returning the final route and any errors.
 func (c *Client) Apply(ctx context.Context, f Function) (string, Function, error) {
-	if !f.Initialized() {
-		return c.New(ctx, f)
-	} else {
+	if f.Initialized() {
 		return c.Update(ctx, f)
+	} else {
+		return c.New(ctx, f)
 	}
 }
 
@@ -426,7 +428,8 @@ func (c *Client) Apply(ctx context.Context, f Function) (string, Function, error
 // Updates a function which has already been initialized to run the latest
 // source code.
 //
-// Use Init, Build, Push and Deploy independently for lower level control.
+// Use Apply for higher level control. Use Init, Build, Push and Deploy
+// independently for lower level control.
 // Returns final primary route to the Function and any errors.
 func (c *Client) Update(ctx context.Context, f Function) (string, Function, error) {
 	if !f.Initialized() {
@@ -451,7 +454,8 @@ func (c *Client) Update(ctx context.Context, f Function) (string, Function, erro
 // Function. Used by Apply when the path is not yet an initialized function.
 // Errors if the path is alrady an initialized function.
 //
-// Use Init, Build, Push, Deploy etc. independently for lower level control.
+// Use Apply for higher level control.  Use Init, Build, Push, Deploy
+// independently for lower level control.
 // Returns the primary route to the function or error.
 func (c *Client) New(ctx context.Context, cfg Function) (string, Function, error) {
 	c.progressListener.SetTotal(3)
@@ -627,49 +631,15 @@ func (c *Client) Build(ctx context.Context, f Function) (Function, error) {
 // It also updates the included symlink to function source 'f' to point to
 // the current function's source.
 func (c *Client) Scaffold(ctx context.Context, f Function, dest string) (err error) {
-	// First get a reference to the repository containing the scaffolding to use
-	//
-	// TODO: In order to support extensible scaffolding from external repositories,
-	// Retain the repository reference from which a Function was initialized
-	// in order to re-read out its scaffolding later.  This can be the locally-
-	// installed repository name or the remote reference URL.  There are benefits
-	// and detriments either way.  A third option would be to store the
-	// scaffolding locally, but this also has downsides.
-	//
-	//  If function creatd from a local repository named:
-	//     repo = repoFromURL(f.RepoURL)
-	//  If function created from a remote reference:
-	//    c.Repositories().Get(f.RepoName)
-	//  If function not created from an external repository:
-	repo, err := c.Repositories().Get(DefaultRepositoryName)
-	if err != nil {
-		return
-	}
-
-	// Detect the method signature
-	s, err := functionSignature(f)
+	repo, err := NewRepository("", "") // default (embedded) repository
 	if err != nil {
 		return
 	}
-
-	// Write Scaffolding from the Repository into the destination
-	if err = repo.WriteScaffolding(ctx, f, s, dest); err != nil {
-		return
-	}
-
-	// Replace the 'f' link of the scaffolding (which is now incorrect) to
-	// link to the function's root.
-	src, err := filepath.Rel(dest, f.Root)
-	if err != nil {
-		return fmt.Errorf("error determining relative path to function source %w", err)
-	}
-	_ = os.Remove(filepath.Join(dest, "f"))
-	if err = os.Symlink(src, filepath.Join(dest, "f")); err != nil {
-		return fmt.Errorf("error linking scaffolding to function source %w", err)
-	}
-	return
+	return scaffolding.Write(dest, f.Root, f.Runtime, f.Invoke, repo.FS())
 }
 
+// printBuildActivity is a helper for ensuring the user gets feedback from
+// the long task of containerized builds.
 func (c *Client) printBuildActivity(ctx context.Context) {
 	m := []string{
 		"Still building",

pkg/functions/job.go

@@ -45,6 +45,9 @@ func NewJob(f Function, host, port string, errs chan error, onStop func() error,
 	if j.Errors == nil {
 		j.Errors = make(chan error, 1)
 	}
+	if j.onStop == nil {
+		j.onStop = func() error { return nil }
+	}
 	if err = cleanupJobDirs(j); err != nil {
 		return
 	}

pkg/functions/repository.go

@@ -1,7 +1,6 @@
 package functions
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"net/url"
@@ -156,6 +155,11 @@ func NewRepository(name, uri string) (r Repository, err error) {
 	return
 }
 
+// FS returns the underlying filesystem of this repository.
+func (r Repository) FS() filesystem.Filesystem {
+	return r.fs
+}
+
 // filesystemFromURI returns a filesystem from the data located at the
 // given URI.  If URI is not provided, indicates the embedded repo should
 // be loaded.  URI can be a remote git repository (http:// https:// etc.),
@@ -525,30 +529,6 @@ func (r *Repository) Write(dest string) (err error) {
 	return filesystem.CopyFromFS(".", dest, fs)
 }
 
-// WriteScaffolding code to the given path.
-//
-// Scaffolding is a language-level operation which first detects the method
-// signature used by the function's source code and then writes the
-// appropriate scaffolding.
-//
-// NOTE: Scaffoding is not per-template, because a template is merely an
-// example starting point for a Function implementation and should have no
-// bearing on the shape that function can eventually take.  The language,
-// and optionally invocation hint (For cloudevents) are used for this.  For
-// example, there can be multiple templates which exemplify a given method
-// signature, and the implementation can be switched at any time by the author.
-// Language, by contrast, is fixed at time of initialization.
-func (r *Repository) WriteScaffolding(ctx context.Context, f Function, s Signature, dest string) error {
-	if r.fs == nil {
-		return errors.New("repository has no filesystem")
-	}
-	path := fmt.Sprintf("%v/scaffolding/%v", f.Runtime, s.String()) // fs uses / on all OSs
-	if _, err := r.fs.Stat(path); err != nil {
-		return fmt.Errorf("no scaffolding found for '%v' signature '%v'. %v.", f.Runtime, s, err)
-	}
-	return filesystem.CopyFromFS(path, dest, r.fs)
-}
-
 // URL attempts to read the remote git origin URL of the repository.  Best
 // effort; returns empty string if the repository is not a git repo or the repo
 // has been mutated beyond recognition on disk (ex: removing the origin remote)

pkg/functions/runner.go

@@ -138,7 +138,8 @@ func runGo(ctx context.Context, job *Job) (err error) {
 	// cmd.Cancel = stop // TODO: use when we upgrade to go 1.20
 	if job.Host != "127.0.0.1" {
 		//  TODO: Update the functions go runtime to accept LISTEN_ADDRESS rather
-		// than just port
+		// than just port in able to allow listening on other interfaces
+		// (keeping the default localhost only)
 		fmt.Fprintf(os.Stderr, "Warning: the Go functions runtime currently only supports localhost '127.0.0.1'.  Requested listen interface '%v' will be ignored.", job.Host)
 	}
 	// See the 1.19 [release notes](https://tip.golang.org/doc/go1.19) which state:

pkg/functions/runner_test.go

@@ -46,6 +46,11 @@ func TestRunner(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	defer func() {
+		if err := job.Stop(); err != nil {
+			t.Fatalf("error on job stop: %v", err)
+		}
+	}()
 
 	// Invoke
 	resp, err := http.Get(fmt.Sprintf("http://%s:%s", job.Host, job.Port))

pkg/oci/builder.go

@@ -12,6 +12,7 @@ import (
 	v1 "github.com/google/go-containerregistry/pkg/v1"
 
 	fn "knative.dev/func/pkg/functions"
+	"knative.dev/func/pkg/scaffolding"
 )
 
 var path = filepath.Join
@@ -73,26 +74,19 @@ func (b *Builder) Build(ctx context.Context, f fn.Function) (err error) {
 	}
 	defer teardown(cfg)
 
-	//TODO: Use scaffold package when merged:
-	/*
-		if err = scaffolding.Scaffold(ctx, f, cfg.buildDir()); err != nil {
-			return
-		}
-	*/
-	// IN the meantime, use an airball mainfile
-	data := `
-package main
-
-import "fmt"
+	// Load the embedded repository
+	repo, err := fn.NewRepository("", "")
+	if err != nil {
+		return
+	}
 
-func main () {
-  fmt.Println("Hello, world!")
-}
-`
-	if err = os.WriteFile(path(cfg.buildDir(), "main.go"), []byte(data), 0664); err != nil {
+	// Write out the scaffolding
+	err = scaffolding.Write(cfg.buildDir(), f.Root, f.Runtime, f.Invoke, repo.FS())
+	if err != nil {
 		return
 	}
 
+	// Create an OCI container from the scaffolded function
 	if err = containerize(cfg); err != nil {
 		return
 	}