fix: set output_plugin_libraries for gated PG minor versions

changes/unreleased/Fixed-20260812-123144.yaml

@@ -0,0 +1,3 @@
+kind: Fixed
+body: Enable spock_output for Postgres 16.15+, 17.11+, and 18.5+ to restore replication slot creation.
+time: 2026-08-12T12:31:44.954828+05:30

server/internal/orchestrator/common/patroni_config_generator.go

@@ -12,6 +12,7 @@ import (
 
 	"github.com/alessio/shellescape"
 	"github.com/pgEdge/control-plane/server/internal/database"
+	"github.com/pgEdge/control-plane/server/internal/ds"
 	"github.com/pgEdge/control-plane/server/internal/patroni"
 	"github.com/pgEdge/control-plane/server/internal/postgres"
 	"github.com/pgEdge/control-plane/server/internal/postgres/hba"
@@ -59,6 +60,9 @@ type PatroniConfigGenerator struct {
 	PatroniAllowlist []string `json:"patroni_allowlist"`
 	// PatroniPort is the port that Patroni will listen on.
 	PatroniPort int `json:"patroni_port"`
+	// PgEdgeVersion is the Postgres/Spock version for this instance. This is
+	// used to gate version-specific default Postgres parameters.
+	PgEdgeVersion *ds.PgEdgeVersion `json:"pg_edge_version,omitempty"`
 	// PgHbaConf are user-supplied pg_hba.conf entries (one rule per element),
 	// inserted in the user zone after the CP rules and before the catch-all.
 	PgHbaConf []string `json:"pg_hba_conf,omitempty"`
@@ -144,6 +148,7 @@ func NewPatroniConfigGenerator(opts PatroniConfigGeneratorOptions) *PatroniConfi
 		NodeSize:               opts.Instance.NodeSize,
 		OrchestratorParameters: opts.OrchestratorParameters,
 		PatroniPort:            opts.PatroniPort,
+		PgEdgeVersion:          opts.Instance.PgEdgeVersion,
 		PostgresCertsDir:       opts.Paths.Instance.PostgresCertificates(),
 		PostgresPort:           opts.PostgresPort,
 		RestoreCommand:         restoreCommand,
@@ -207,7 +212,7 @@ func (p *PatroniConfigGenerator) AuthMethod() hba.AuthMethod {
 }
 
 func (p *PatroniConfigGenerator) parameters() map[string]any {
-	parameters := postgres.DefaultGUCs()
+	parameters := postgres.DefaultGUCs(p.PgEdgeVersion)
 	maps.Copy(parameters, postgres.SpockDefaultGUCs())
 	maps.Copy(parameters, postgres.DefaultTunableGUCs(p.MemoryBytes, p.CPUs, p.ClusterSize))
 	maps.Copy(parameters, map[string]any{

server/internal/postgres/gucs.go

@@ -2,10 +2,43 @@ package postgres
 
 import (
 	"math"
+
+	"github.com/pgEdge/control-plane/server/internal/ds"
 )
 
-func DefaultGUCs() map[string]any {
-	return map[string]any{
+// minOutputPluginLibrariesVersions are the earliest Postgres minor version per
+// major version that gates output plugins behind the output_plugin_libraries
+// allowlist GUC. Any major version newer than the last entry here is assumed
+// to require it as well. See SPOC-651 / PLAT-721.
+var minOutputPluginLibrariesVersions = map[uint64]*ds.Version{
+	16: ds.MustParseVersion("16.15"),
+	17: ds.MustParseVersion("17.11"),
+	18: ds.MustParseVersion("18.5"),
+}
+
+// needsOutputPluginLibraries reports whether the given Postgres version
+// requires output_plugin_libraries to be set in order to allow spock_output
+// to create replication slots.
+func needsOutputPluginLibraries(version *ds.PgEdgeVersion) bool {
+	if version == nil || version.PostgresVersion == nil {
+		return false
+	}
+	pgVersion := version.PostgresVersion.MajorMinorVersion()
+	major, ok := pgVersion.Major()
+	if !ok {
+		return false
+	}
+	minVersion, ok := minOutputPluginLibrariesVersions[major]
+	if !ok {
+		// Newer majors than we know about are assumed to need it; older
+		// majors than we know about never had the gate.
+		return major > 18
+	}
+	return pgVersion.Compare(minVersion) >= 0
+}
+
+func DefaultGUCs(version *ds.PgEdgeVersion) map[string]any {
+	gucs := map[string]any{
 		"archive_command":              "/bin/true",
 		"archive_mode":                 "on",
 		"checkpoint_completion_target": "0.9",
@@ -28,6 +61,10 @@ func DefaultGUCs() map[string]any {
 		"wal_log_hints":                "on",
 		"wal_sender_timeout":           "5s",
 	}
+	if needsOutputPluginLibraries(version) {
+		gucs["output_plugin_libraries"] = "pgoutput, test_decoding, spock_output"
+	}
+	return gucs
 }
 
 func SpockDefaultGUCs() map[string]any {

server/internal/postgres/gucs_test.go

@@ -5,11 +5,40 @@ import (
 
 	"github.com/stretchr/testify/assert"
 
+	"github.com/pgEdge/control-plane/server/internal/ds"
 	"github.com/pgEdge/control-plane/server/internal/postgres"
 )
 
 func TestDefaultGUCs(t *testing.T) {
-	assert.Equal(t, "scram-sha-256", postgres.DefaultGUCs()["password_encryption"])
+	assert.Equal(t, "scram-sha-256", postgres.DefaultGUCs(nil)["password_encryption"])
+}
+
+func TestDefaultGUCsOutputPluginLibraries(t *testing.T) {
+	for _, tc := range []struct {
+		name            string
+		version         *ds.PgEdgeVersion
+		expectedPresent bool
+	}{
+		{name: "nil version", version: nil, expectedPresent: false},
+		{name: "pg16 below gate", version: ds.MustParsePgEdgeVersion("16.14", "4"), expectedPresent: false},
+		{name: "pg16 at gate", version: ds.MustParsePgEdgeVersion("16.15", "4"), expectedPresent: true},
+		{name: "pg16 above gate", version: ds.MustParsePgEdgeVersion("16.16", "4"), expectedPresent: true},
+		{name: "pg17 below gate", version: ds.MustParsePgEdgeVersion("17.10", "4"), expectedPresent: false},
+		{name: "pg17 at gate", version: ds.MustParsePgEdgeVersion("17.11", "4"), expectedPresent: true},
+		{name: "pg18 below gate", version: ds.MustParsePgEdgeVersion("18.4", "4"), expectedPresent: false},
+		{name: "pg18 at gate", version: ds.MustParsePgEdgeVersion("18.5", "4"), expectedPresent: true},
+		{name: "future major", version: ds.MustParsePgEdgeVersion("19.0", "4"), expectedPresent: true},
+		{name: "older major", version: ds.MustParsePgEdgeVersion("15.10", "4"), expectedPresent: false},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			gucs := postgres.DefaultGUCs(tc.version)
+			value, ok := gucs["output_plugin_libraries"]
+			assert.Equal(t, tc.expectedPresent, ok)
+			if tc.expectedPresent {
+				assert.Equal(t, "pgoutput, test_decoding, spock_output", value)
+			}
+		})
+	}
 }
 
 func TestDefaultTunableGUCs(t *testing.T) {