roachtest: serializable cluster options

Previously, a list of cluster options was not serializable to YAML (due to the
functional and dynamic nature of how a cluster option is implemented). This is
required to eventually support serializing mixedversion plans, since some of the
steps in the plan keep a list of cluster options that need to be applied to a
cluster.

This change uses the codec package to enable serializing a list of cluster
options.

Informs: #149451, #151461

Epic: None
Release note: None

Author: herkolategan

pkg/gen/misc.bzl

@@ -11,6 +11,7 @@ MISC_SRCS = [
     "//pkg/kv/kvserver/concurrency:keylocks_interval_btree_test.go",
     "//pkg/kv/kvserver/spanlatch:latch_interval_btree.go",
     "//pkg/kv/kvserver/spanlatch:latch_interval_btree_test.go",
+    "//pkg/roachprod/install:types_generated.go",
     "//pkg/roachprod/vm/aws:terraform/main.tf",
     "//pkg/spanconfig/spanconfigstore:entry_interval_btree.go",
     "//pkg/spanconfig/spanconfigstore:entry_interval_btree_test.go",

pkg/roachprod/install/BUILD.bazel

@@ -16,6 +16,7 @@ go_library(
         "services.go",
         "session.go",
         "staging.go",
+        ":typegen-cluster-settings",  # keep
     ],
     embedsrcs = [
         "files/cockroachdb-logging.yaml",
@@ -34,6 +35,7 @@ go_library(
         "//pkg/roachprod/errors",
         "//pkg/roachprod/logger",
         "//pkg/roachprod/roachprodutil",
+        "//pkg/roachprod/roachprodutil/codec",
         "//pkg/roachprod/ssh",
         "//pkg/roachprod/ui",
         "//pkg/roachprod/vm",
@@ -49,6 +51,7 @@ go_library(
         "@com_github_alessio_shellescape//:shellescape",
         "@com_github_cockroachdb_errors//:errors",
         "@com_github_cockroachdb_version//:version",
+        "@in_gopkg_yaml_v3//:yaml_v3",
         "@org_golang_x_exp//maps",
         "@org_golang_x_sync//errgroup",
         "@org_golang_x_sys//unix",
@@ -58,6 +61,7 @@ go_library(
 go_test(
     name = "install_test",
     srcs = [
+        "cluster_settings_test.go",
         "cluster_synced_test.go",
         "cockroach_test.go",
         "expander_test.go",
@@ -84,5 +88,22 @@ go_test(
         "@com_github_cockroachdb_datadriven//:datadriven",
         "@com_github_cockroachdb_errors//:errors",
         "@com_github_stretchr_testify//require",
+        "@in_gopkg_yaml_v3//:yaml_v3",
+    ],
+)
+
+genrule(
+    name = "typegen-cluster-settings",
+    srcs = ["cluster_settings.go"],
+    outs = ["types_generated.go"],
+    cmd = """$(location //pkg/roachprod/roachprodutil/codec/cmd/typegen:typegen) \
+       -output $@ $(location cluster_settings.go)
+""",
+    tools = [
+        "//pkg/roachprod/roachprodutil/codec/cmd/typegen",
+    ],
+    visibility = [
+        ":__pkg__",
+        "//pkg/gen:__pkg__",
     ],
 )

pkg/roachprod/install/cluster_settings.go

@@ -9,8 +9,10 @@ import (
 	"fmt"
 
 	"github.com/cockroachdb/cockroach/pkg/roachprod/config"
+	"github.com/cockroachdb/cockroach/pkg/roachprod/roachprodutil/codec"
 	"github.com/cockroachdb/cockroach/pkg/roachprod/vm/gce"
 	"github.com/cockroachdb/errors"
+	"gopkg.in/yaml.v3"
 )
 
 // ClusterSettings contains various knobs that affect operations on a cluster.
@@ -40,10 +42,12 @@ type secureFlagsOpt struct {
 
 // ClusterSettingOption is the interface satisfied by options to MakeClusterSettings.
 type ClusterSettingOption interface {
+	codec.DynamicType
 	apply(settings *ClusterSettings)
 }
 
 // ClusterSettingsOption adds cluster settings via SET CLUSTER SETTING.
+// typegen:reg
 type ClusterSettingsOption map[string]string
 
 func (o ClusterSettingsOption) apply(settings *ClusterSettings) {
@@ -53,20 +57,23 @@ func (o ClusterSettingsOption) apply(settings *ClusterSettings) {
 }
 
 // TagOption is used to pass a process tag.
+// typegen:reg
 type TagOption string
 
 func (o TagOption) apply(settings *ClusterSettings) {
 	settings.Tag = string(o)
 }
 
 // BinaryOption is used to pass a process tag.
+// typegen:reg
 type BinaryOption string
 
 func (o BinaryOption) apply(settings *ClusterSettings) {
 	settings.Binary = string(o)
 }
 
 // PGUrlCertsDirOption is used to pass certs dir for secure connections.
+// typegen:reg
 type PGUrlCertsDirOption string
 
 func (o PGUrlCertsDirOption) apply(settings *ClusterSettings) {
@@ -75,6 +82,7 @@ func (o PGUrlCertsDirOption) apply(settings *ClusterSettings) {
 
 // ComplexSecureOption is a complex type for secure options that keeps track of
 // the user's intent regarding security.
+// typegen:reg
 type ComplexSecureOption secureFlagsOpt
 
 func (o ComplexSecureOption) apply(settings *ClusterSettings) {
@@ -126,6 +134,7 @@ func (o ComplexSecureOption) overrideBasedOnClusterSettings(c *SyncedCluster) er
 
 // SimpleSecureOption is a simple type that simplifies setting the secure flags
 // in the cluster settings without keeping track of --secure or --insecure options.
+// typegen:reg
 type SimpleSecureOption bool
 
 func (o SimpleSecureOption) apply(settings *ClusterSettings) {
@@ -150,13 +159,15 @@ type SecureOption interface {
 }
 
 // UseTreeDistOption is passed to use treedist copy algorithm.
+// typegen:reg
 type UseTreeDistOption bool
 
 func (o UseTreeDistOption) apply(settings *ClusterSettings) {
 	settings.UseTreeDist = bool(o)
 }
 
 // EnvOption is used to pass environment variables to the cockroach process.
+// typegen:reg
 type EnvOption []string
 
 var _ EnvOption
@@ -166,6 +177,7 @@ func (o EnvOption) apply(settings *ClusterSettings) {
 }
 
 // NumRacksOption is used to pass the number of racks to partition the nodes into.
+// typegen:reg
 type NumRacksOption int
 
 var _ NumRacksOption
@@ -175,6 +187,7 @@ func (o NumRacksOption) apply(settings *ClusterSettings) {
 }
 
 // DebugDirOption is used to stash debug information.
+// typegen:reg
 type DebugDirOption string
 
 var _ DebugDirOption
@@ -201,3 +214,20 @@ func MakeClusterSettings(opts ...ClusterSettingOption) ClusterSettings {
 	}
 	return clusterSettings
 }
+
+// ClusterSettingOptionList is a list of ClusterSettingOption that can be
+// serialized to YAML. It uses codec.ListWrapper to handle the dynamic types.
+type ClusterSettingOptionList []ClusterSettingOption
+
+func (o ClusterSettingOptionList) MarshalYAML() (any, error) {
+	return codec.WrapList(o), nil
+}
+
+func (o *ClusterSettingOptionList) UnmarshalYAML(value *yaml.Node) error {
+	var lw codec.ListWrapper[ClusterSettingOption]
+	if err := value.Decode(&lw); err != nil {
+		return err
+	}
+	*o = lw.Get()
+	return nil
+}

pkg/roachprod/install/cluster_settings_test.go

@@ -0,0 +1,32 @@
+// Copyright 2025 The Cockroach Authors.
+//
+// Use of this software is governed by the CockroachDB Software License
+// included in the /LICENSE file.
+
+package install
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gopkg.in/yaml.v3"
+)
+
+func TestClusterSettingOptionListCodec(t *testing.T) {
+	opts := ClusterSettingOptionList{
+		NumRacksOption(1),
+		DebugDirOption("foo"),
+	}
+	data, err := yaml.Marshal(opts)
+	require.NoError(t, err)
+
+	var decOpts ClusterSettingOptionList
+	dec := yaml.NewDecoder(bytes.NewReader(data))
+	dec.KnownFields(true)
+	err = dec.Decode(&decOpts)
+	require.NoError(t, err)
+
+	require.Equal(t, opts, decOpts)
+	require.Equal(t, MakeClusterSettings(opts...), MakeClusterSettings(decOpts...))
+}