Public API Separation

[codefromthecrypt]

Previously, an api package was added, but it also put the implementation there. This causes package cycle problems and subverts the idea of an API.

This migrates api.Run (impl) to api.RunFunc (api) and func_e.Run (impl). This also backfills a test to make sure the code works.

To do this, we migrate /main.go -> /cmd/func-e/main.go, which allows us to re-use the root package as a library, instead of a binary (main) one.

There is impact, but to only one user: envoy gateway. The fix is mechanical and allows us to clear tech debt before making more features.

diff --git a/internal/infrastructure/host/proxy_infra.go b/internal/infrastructure/host/proxy_infra.go
index f384b6854..229fdcd1c 100644
--- a/internal/infrastructure/host/proxy_infra.go
+++ b/internal/infrastructure/host/proxy_infra.go
@@ -12,7 +12,8 @@ import (
        "os"
        "path/filepath"

-       funcE "github.com/tetratelabs/func-e/api"
+       func_e "github.com/tetratelabs/func-e"
+       "github.com/tetratelabs/func-e/api"
        "k8s.io/utils/ptr"

        egv1a1 "github.com/envoyproxy/gateway/api/v1alpha1"
@@ -92,7 +93,7 @@ func (i *Infra) runEnvoy(ctx context.Context, out io.Writer, name string, args [
                defer func() {
                        exit <- struct{}{}
                }()
-               err := funcE.Run(pCtx, args, funcE.HomeDir(i.HomeDir), funcE.Out(out))
+               err := func_e.Run(pCtx, args, api.HomeDir(i.HomeDir), api.Out(out))
                if err != nil {
                        i.Logger.Error(err, "failed to run envoy")
                }
diff --git a/internal/infrastructure/host/proxy_infra_test.go b/internal/infrastructure/host/proxy_infra_test.go
index 2d82cc689..36bc997f0 100644
--- a/internal/infrastructure/host/proxy_infra_test.go
+++ b/internal/infrastructure/host/proxy_infra_test.go
@@ -13,7 +13,8 @@ import (
        "testing"

        "github.com/stretchr/testify/require"
-       funcE "github.com/tetratelabs/func-e/api"
+       func_e "github.com/tetratelabs/func-e"
+       "github.com/tetratelabs/func-e/api"

        egv1a1 "github.com/envoyproxy/gateway/api/v1alpha1"
        "github.com/envoyproxy/gateway/internal/crypto"
@@ -91,7 +92,7 @@ func TestInfraCreateProxy(t *testing.T) {
 func TestInfra_runEnvoy_stopEnvoy(t *testing.T) {
        tmpdir := t.TempDir()
        // Ensures that all the required binaries are available.
-       err := funcE.Run(context.Background(), []string{"--version"}, funcE.HomeDir(tmpdir))
+       err := func_e.Run(context.Background(), []string{"--version"}, api.HomeDir(tmpdir))
        require.NoError(t, err)

        i := &Infra{proxyContextMap: make(map[string]*proxyContext), HomeDir: tmpdir}

[codefromthecrypt]

this uses an internal type which is a trick to effectively hide the exported fields

[codefromthecrypt]

versionsServer is ignored when you supply the internal-only envoyPath, so this makes the tests run slightly quicker

[codefromthecrypt]

note: I don't think RunFunc is the best api, but it allows a mechanical update to existing envoy gateway code. We can make another better (second) API once things are updated, provided we don't put impl in the api package again.

[codefromthecrypt]

once this is merged and after next release we need to fix homebrew to system "go", "build", *std_go_args(ldflags:), "./cmd/func-e" (add trailing , "./cmd/func-e")