Add LLOConfigMode in preparation for blue/green deploys (#14634)

- Currently only "mercury" is supported, in future additional config
  modes will be available

core/services/ocr2/plugins/llo/integration_test.go

@@ -255,6 +255,7 @@ func TestIntegration_LLO(t *testing.T) {
 chainID = "%s"
 fromBlock = %d
 lloDonID = %d
+lloConfigMode = "mercury"
 `, chainID, fromBlock, donID)
 		addBootstrapJob(t, bootstrapNode, configuratorAddress, "job-2", relayType, relayConfig)
 

core/services/relay/evm/evm.go

@@ -477,6 +477,12 @@ func (r *Relayer) NewLLOProvider(rargs commontypes.RelayArgs, pargs commontypes.
 			return nil, fmt.Errorf("failed to get relay config: %w", err)
 		}
 	}
+	if relayConfig.LLODONID == 0 {
+		return nil, errors.New("donID must be specified in relayConfig for LLO jobs")
+	}
+	if relayConfig.LLOConfigMode != types.LLOConfigModeMercury {
+		return nil, fmt.Errorf("LLOConfigMode must be specified in relayConfig for LLO jobs (only %q is currently supported)", types.LLOConfigModeMercury)
+	}
 
 	var lloCfg lloconfig.PluginConfig
 	if err := json.Unmarshal(pargs.PluginConfig, &lloCfg); err != nil {

core/services/relay/evm/types/types.go

@@ -173,6 +173,16 @@ func (r *ReadType) UnmarshalText(text []byte) error {
 	return fmt.Errorf("unrecognized ReadType: %s", string(text))
 }
 
+type LLOConfigMode string
+
+const (
+	LLOConfigModeMercury LLOConfigMode = "mercury"
+)
+
+func (c LLOConfigMode) String() string {
+	return string(c)
+}
+
 type RelayConfig struct {
 	ChainID                *big.Big           `json:"chainID"`
 	FromBlock              uint64             `json:"fromBlock"`
@@ -192,7 +202,8 @@ type RelayConfig struct {
 	EnableTriggerCapability bool         `json:"enableTriggerCapability"`
 
 	// LLO-specific
-	LLODONID uint32 `json:"lloDonID" toml:"lloDonID"`
+	LLODONID      uint32        `json:"lloDonID" toml:"lloDonID"`
+	LLOConfigMode LLOConfigMode `json:"lloConfigMode" toml:"lloConfigMode"`
 }
 
 var ErrBadRelayConfig = errors.New("bad relay config")