fix: support custom CL for MEV builder (issue #627)

src/el/reth/reth_launcher.star

@@ -7,6 +7,8 @@ node_metrics = import_module("../../node_metrics_info.star")
 constants = import_module("../../package_io/constants.star")
 mev_rs_builder = import_module("../../mev/mev-rs/mev_builder/mev_builder_launcher.star")
 lighthouse = import_module("../../cl/lighthouse/lighthouse_launcher.star")
+prysm = import_module("../../cl/prysm/prysm_launcher.star")
+teku = import_module("../../cl/teku/teku_launcher.star")
 flashbots_rbuilder = import_module(
     "../../mev/flashbots/mev_builder/mev_builder_launcher.star"
 )
@@ -289,13 +291,23 @@ def get_config(
         files[
             flashbots_rbuilder.MEV_BUILDER_MOUNT_DIRPATH_ON_SERVICE
         ] = flashbots_rbuilder.MEV_BUILDER_FILES_ARTIFACT_NAME
+
+        # Infer builder CL type from image and get correct port
+        # Note: Only Lighthouse, Lodestar, Prysm, and Teku are supported as builder CLs.
+        mev_cl_image = launcher.mev_params.mev_builder_cl_image
+        mev_cl_port = lighthouse.BEACON_HTTP_PORT_NUM  # default
+        if constants.CL_TYPE.prysm in mev_cl_image:
+            mev_cl_port = prysm.BEACON_HTTP_PORT_NUM
+        elif constants.CL_TYPE.teku in mev_cl_image:
+            mev_cl_port = teku.BEACON_HTTP_PORT_NUM
+
         env_vars.update(
             {
                 "CL_ENDPOINT": "http://cl-{0}-{1}-{2}:{3}".format(
                     participant_index + 1,
                     cl_client_name,
                     constants.EL_TYPE.reth_builder,
-                    lighthouse.BEACON_HTTP_PORT_NUM,
+                    mev_cl_port,
                 ),
             }
         )

src/mev/flashbots/mev_builder/mev_builder_launcher.star

@@ -5,6 +5,9 @@ constants = import_module("../../../package_io/constants.star")
 flashbots_relay = import_module("../mev_relay/mev_relay_launcher.star")
 helix_relay = import_module("../../helix/helix_relay_launcher.star")
 lighthouse = import_module("../../../cl/lighthouse/lighthouse_launcher.star")
+prysm = import_module("../../../cl/prysm/prysm_launcher.star")
+teku = import_module("../../../cl/teku/teku_launcher.star")
+
 # MEV Builder flags
 
 MEV_BUILDER_CONFIG_FILENAME = "config.toml"
@@ -28,6 +31,27 @@ def new_builder_config(
     num_of_participants = shared_utils.zfill_custom(
         len(participants), len(str(len(participants)))
     )
+    # Infer the builder CL type from the provided image so CLEndpoint is correct
+    # Note: Only Lighthouse, Prysm, and Teku are supported as builder CLs.
+    # Lodestar, Nimbus, and Grandine have incompatible payload_attributes SSE event formats.
+    mev_cl_image = mev_params.mev_builder_cl_image
+    mev_cl_type = constants.CL_TYPE.lighthouse
+    for candidate in [
+        constants.CL_TYPE.lighthouse,
+        constants.CL_TYPE.prysm,
+        constants.CL_TYPE.teku,
+    ]:
+        if candidate in mev_cl_image:
+            mev_cl_type = candidate
+            break
+
+    # Map CL type to its beacon HTTP port constant
+    mev_cl_port = lighthouse.BEACON_HTTP_PORT_NUM
+    if mev_cl_type == constants.CL_TYPE.prysm:
+        mev_cl_port = prysm.BEACON_HTTP_PORT_NUM
+    elif mev_cl_type == constants.CL_TYPE.teku:
+        mev_cl_port = teku.BEACON_HTTP_PORT_NUM
+
     builder_template_data = new_builder_config_template_data(
         network_params,
         constants.DEFAULT_MEV_PUBKEY,
@@ -38,6 +62,8 @@ def new_builder_config(
         num_of_participants,
         mev_params.mev_builder_subsidy,
         mev_type,
+        mev_cl_type,
+        mev_cl_port,
     )
     flashbots_builder_config_template = read_file(
         static_files.FLASHBOTS_RBUILDER_CONFIG_FILEPATH
@@ -73,6 +99,8 @@ def new_builder_config_template_data(
     num_of_participants,
     subsidy,
     mev_type,
+    builder_cl_type,
+    builder_cl_port,
 ):
     # Determine relay service name and port based on MEV type
     if mev_type == constants.HELIX_MEV_TYPE:
@@ -91,9 +119,9 @@ def new_builder_config_template_data(
         "DataDir": "/data/reth/execution-data",
         "CLEndpoint": "http://cl-{0}-{1}-{2}:{3}".format(
             num_of_participants,
-            constants.CL_TYPE.lighthouse,
+            builder_cl_type,
             constants.EL_TYPE.reth_builder,
-            lighthouse.BEACON_HTTP_PORT_NUM,
+            builder_cl_port,
         ),
         "GenesisForkVersion": constants.GENESIS_FORK_VERSION,
         "Relay": relay_service,

src/package_io/input_parser.star

@@ -1865,6 +1865,58 @@ def enrich_disable_peer_scoring(parsed_arguments_dict):
     return parsed_arguments_dict
 
 
+def infer_cl_type_from_image(cl_image):
+    """Infer CL client type from given config.
+
+    Note: Only Lighthouse, Prysm, and Teku are supported as builder CLs.
+    Lodestar, Nimbus, and Grandine have incompatible payload_attributes SSE event formats.
+    """
+    for candidate in [
+        constants.CL_TYPE.lighthouse,
+        constants.CL_TYPE.prysm,
+        constants.CL_TYPE.teku,
+    ]:
+        if candidate in cl_image:
+            return candidate
+    return constants.CL_TYPE.lighthouse  # default
+
+
+def get_mev_cl_extra_params(cl_type, mev_url, include_supernode=False):
+    """Return CL-specific builder flags for MEV participant.
+
+    For MEV builder nodes, the CL needs to prepare payloads for EVERY slot,
+    not just slots where the validator is proposing. This requires special flags.
+
+    Note: Only Lighthouse, Prysm, and Teku are supported as builder CLs.
+    Lodestar, Nimbus, and Grandine have incompatible payload_attributes SSE event formats.
+    """
+    params = []
+    if cl_type == constants.CL_TYPE.lighthouse:
+        params.extend(
+            [
+                "--builder={0}".format(mev_url),
+                "--always-prepare-payload",
+                "--prepare-payload-lookahead",
+                "8000",
+                "--disable-peer-scoring",
+            ]
+        )
+        if include_supernode:
+            params.append("--supernode")
+    elif cl_type == constants.CL_TYPE.teku:
+        params.append("--builder-endpoint={0}".format(mev_url))
+        params.append("--validators-builder-registration-default-enabled=true")
+        # BUILDER_ALWAYS ensures builder is always used for payload construction
+        params.append("--builder-bid-compare-factor=BUILDER_ALWAYS")
+        # This flag makes Teku send payload_attributes on every slot (required for block builders)
+        params.append("--Xfork-choice-updated-always-send-payload-attributes=true")
+    elif cl_type == constants.CL_TYPE.prysm:
+        params.append("--http-mev-relay={0}".format(mev_url))
+        # prepare-all-payloads tells Prysm to prepare payloads for every slot (required for builders)
+        params.append("--prepare-all-payloads")
+    return params
+
+
 # TODO perhaps clean this up into a map
 def enrich_mev_extra_params(parsed_arguments_dict, mev_prefix, mev_port, mev_type):
     for index, participant in enumerate(parsed_arguments_dict["participants"]):
@@ -1943,13 +1995,6 @@ def enrich_mev_extra_params(parsed_arguments_dict, mev_prefix, mev_port, mev_typ
                 "el_image": parsed_arguments_dict["mev_params"]["mev_builder_image"],
                 "cl_image": parsed_arguments_dict["mev_params"]["mev_builder_cl_image"],
                 "cl_log_level": parsed_arguments_dict["global_log_level"],
-                "cl_extra_params": [
-                    "--always-prepare-payload",
-                    "--prepare-payload-lookahead",
-                    "8000",
-                    "--disable-peer-scoring",
-                    "--supernode",
-                ],
                 "el_extra_params": parsed_arguments_dict["mev_params"][
                     "mev_builder_extra_args"
                 ],
@@ -1960,6 +2005,34 @@ def enrich_mev_extra_params(parsed_arguments_dict, mev_prefix, mev_port, mev_typ
             }
         )
 
+        mev_cl_image = parsed_arguments_dict["mev_params"]["mev_builder_cl_image"]
+        mev_cl_type = infer_cl_type_from_image(mev_cl_image)
+        mev_participant["cl_type"] = mev_cl_type
+        mev_participant["vc_type"] = mev_cl_type
+
+        # Compute mev_url for this mev participant so we can set CL-specific
+        # extra params (different CLs accept different flags).
+        if mev_type == constants.COMMIT_BOOST_MEV_TYPE:
+            prefix = constants.COMMIT_BOOST_SERVICE_NAME_PREFIX
+        else:
+            prefix = constants.MEV_BOOST_SERVICE_NAME_PREFIX
+        num_participants = len(parsed_arguments_dict["participants"])
+        index_str = shared_utils.zfill_custom(
+            num_participants + 1, len(str(num_participants + 1))
+        )
+        mev_url = "http://{0}-{1}-{2}-{3}:{4}".format(
+            prefix,
+            index_str,
+            mev_participant["cl_type"],
+            mev_participant["el_type"],
+            constants.MEV_BOOST_PORT,
+        )
+
+        # Use helper to get CL-specific builder flags (with supernode for Flashbots/CommitBoost/Helix)
+        mev_participant["cl_extra_params"] = get_mev_cl_extra_params(
+            mev_cl_type, mev_url, include_supernode=True
+        )
+
         parsed_arguments_dict["participants"].append(mev_participant)
 
     if mev_type == constants.MEV_RS_MEV_TYPE:
@@ -1970,19 +2043,38 @@ def enrich_mev_extra_params(parsed_arguments_dict, mev_prefix, mev_port, mev_typ
                 "el_image": parsed_arguments_dict["mev_params"]["mev_builder_image"],
                 "cl_image": parsed_arguments_dict["mev_params"]["mev_builder_cl_image"],
                 "cl_log_level": parsed_arguments_dict["global_log_level"],
-                "cl_extra_params": [
-                    "--always-prepare-payload",
-                    "--prepare-payload-lookahead",
-                    "8000",
-                    "--disable-peer-scoring",
-                ],
                 "el_extra_params": parsed_arguments_dict["mev_params"][
                     "mev_builder_extra_args"
                 ],
                 "validator_count": 0,
             }
         )
+
+        mev_cl_image = parsed_arguments_dict["mev_params"]["mev_builder_cl_image"]
+        mev_cl_type = infer_cl_type_from_image(mev_cl_image)
+        mev_participant["cl_type"] = mev_cl_type
+        mev_participant["vc_type"] = mev_cl_type
+
+        prefix = constants.MEV_BOOST_SERVICE_NAME_PREFIX
+        num_participants = len(parsed_arguments_dict["participants"])
+        index_str = shared_utils.zfill_custom(
+            num_participants + 1, len(str(num_participants + 1))
+        )
+        mev_url = "http://{0}-{1}-{2}-{3}:{4}".format(
+            prefix,
+            index_str,
+            mev_participant["cl_type"],
+            mev_participant["el_type"],
+            constants.MEV_BOOST_PORT,
+        )
+
+        # Use helper to get CL-specific builder flags (no supernode for MEV-RS)
+        mev_participant["cl_extra_params"] = get_mev_cl_extra_params(
+            mev_cl_type, mev_url, include_supernode=False
+        )
+
         parsed_arguments_dict["participants"].append(mev_participant)
+
     if mev_type == constants.MOCK_MEV_TYPE:
         parsed_arguments_dict["mev_params"]["mock_mev_image"] = parsed_arguments_dict[
             "mev_params"