feat: implement runtime configuration package with multi-org support (#14624)

runtime configuration package
---------

Signed-off-by: Danny Kopping <danny@coder.com>
Co-authored-by: Danny Kopping <danny@coder.com>

coderd/runtimeconfig/entry_test.go

@@ -0,0 +1,77 @@
+package runtimeconfig_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/coder/coder/v2/coderd/database/dbmem"
+	"github.com/coder/coder/v2/coderd/runtimeconfig"
+	"github.com/coder/coder/v2/testutil"
+	"github.com/coder/serpent"
+)
+
+func TestEntry(t *testing.T) {
+	t.Parallel()
+
+	t.Run("new", func(t *testing.T) {
+		t.Parallel()
+
+		require.Panics(t, func() {
+			// No name should panic
+			runtimeconfig.MustNew[*serpent.Float64]("")
+		})
+
+		require.NotPanics(t, func() {
+			runtimeconfig.MustNew[*serpent.Float64]("my-field")
+		})
+	})
+
+	t.Run("simple", func(t *testing.T) {
+		t.Parallel()
+
+		ctx := testutil.Context(t, testutil.WaitShort)
+		mgr := runtimeconfig.NewManager()
+		db := dbmem.New()
+
+		override := serpent.String("dogfood@dev.coder.com")
+
+		field := runtimeconfig.MustNew[*serpent.String]("string-field")
+
+		// No value set yet.
+		_, err := field.Resolve(ctx, mgr.Resolver(db))
+		require.ErrorIs(t, err, runtimeconfig.ErrEntryNotFound)
+		// Set an org-level override.
+		require.NoError(t, field.SetRuntimeValue(ctx, mgr.Resolver(db), &override))
+		// Value was updated
+		val, err := field.Resolve(ctx, mgr.Resolver(db))
+		require.NoError(t, err)
+		require.Equal(t, override.String(), val.String())
+	})
+
+	t.Run("complex", func(t *testing.T) {
+		t.Parallel()
+
+		ctx := testutil.Context(t, testutil.WaitShort)
+		mgr := runtimeconfig.NewManager()
+		db := dbmem.New()
+
+		override := serpent.Struct[map[string]string]{
+			Value: map[string]string{
+				"a": "b",
+				"c": "d",
+			},
+		}
+
+		field := runtimeconfig.MustNew[*serpent.Struct[map[string]string]]("string-field")
+		// Validate that there is no runtime override right now.
+		_, err := field.Resolve(ctx, mgr.Resolver(db))
+		require.ErrorIs(t, err, runtimeconfig.ErrEntryNotFound)
+		// Set a runtime value
+		require.NoError(t, field.SetRuntimeValue(ctx, mgr.Resolver(db), &override))
+		// Coalesce now returns the org-level value.
+		structVal, err := field.Resolve(ctx, mgr.Resolver(db))
+		require.NoError(t, err)
+		require.Equal(t, override.Value, structVal.Value)
+	})
+}