feat: Allow miner add an arbitrary message into the cellbase

miner/src/block_assembler.rs

@@ -10,12 +10,13 @@ use ckb_core::transaction::{
 };
 use ckb_core::uncle::UncleBlock;
 use ckb_core::BlockNumber;
-use ckb_core::{Bytes, Cycle, Version};
+use ckb_core::{Cycle, Version};
 use ckb_logger::{error, info};
 use ckb_notify::NotifyController;
 use ckb_shared::{shared::Shared, tx_pool::ProposedEntry};
 use ckb_store::ChainStore;
 use ckb_traits::ChainProvider;
+use ckb_verification::TransactionError;
 use crossbeam_channel::{self, select, Receiver, Sender};
 use failure::Error as FailureError;
 use faketime::unix_time_as_millis;
@@ -407,10 +408,14 @@ impl<CS: ChainStore + 'static> BlockAssembler<CS> {
                 .consensus()
                 .genesis_epoch_ext()
                 .block_reward(candidate_number)?,
-            Bytes::default(),
+            self.config.data.clone().into_bytes(),
             self.shared.consensus().bootstrap_lock().clone(),
             None,
         );
+        // User-defined data has a risk of exceeding capacity
+        if output.is_lack_of_capacity()? {
+            return Err(TransactionError::InsufficientCellCapacity.into());
+        }
         Ok(TransactionBuilder::default()
             .input(input)
             .output(output)
@@ -424,7 +429,16 @@ impl<CS: ChainStore + 'static> BlockAssembler<CS> {
 
         let witness = lock.into_witness();
         let input = CellInput::new_cellbase_input(candidate_number);
-        let output = CellOutput::new(block_reward, Bytes::default(), target_lock, None);
+        let output = CellOutput::new(
+            block_reward,
+            self.config.data.clone().into_bytes(),
+            target_lock,
+            None,
+        );
+        // User-defined data has a risk of exceeding capacity
+        if output.is_lack_of_capacity()? {
+            return Err(TransactionError::InsufficientCellCapacity.into());
+        }
         Ok(TransactionBuilder::default()
             .input(input)
             .output(output)
@@ -528,6 +542,7 @@ mod tests {
         let config = BlockAssemblerConfig {
             code_hash: H256::zero(),
             args: vec![],
+            data: JsonBytes::default(),
         };
         let mut block_assembler = setup_block_assembler(shared.clone(), config);
         let mut candidate_uncles = LruCache::new(MAX_CANDIDATE_UNCLES);
@@ -648,6 +663,7 @@ mod tests {
         let config = BlockAssemblerConfig {
             code_hash: H256::zero(),
             args: vec![],
+            data: JsonBytes::default(),
         };
         let block_assembler = setup_block_assembler(shared.clone(), config);
         let new_uncle_receiver = notify.subscribe_new_uncle("test_prepare_uncles");

miner/src/config.rs

@@ -13,4 +13,6 @@ pub struct MinerConfig {
 pub struct BlockAssemblerConfig {
     pub code_hash: H256,
     pub args: Vec<JsonBytes>,
+    #[serde(default)]
+    pub data: JsonBytes,
 }

resource/ckb.toml

@@ -117,8 +117,16 @@ cell_output_cache_size  = 128
 #
 #     ckb cli secp256k1-lock <pubkey>
 #
+# Also, ckb allows the miner to add any data to the cellbase that he has dug out.
+# The data must be A 0x-prefixed hex string. **Please note** that the data cannot be
+# larger than the capacity value of the current cellbase. If it is larger,
+# the block template cannot be obtained normally. That is, it is impossible to mine normally.
+#
+# note: The data field is optional.
+#
 # Below is an example block assembler configuration section:
 #
 # [block_assembler]
 # code_hash = "0xf1951123466e4479842387a66fabfd6b65fc87fd84ae8e6cd3053edb27fff2fd"
 # args = ["ckb cli blake160 <pubkey>"]
+# data = "A 0x-prefixed hex string"

test/src/node.rs

@@ -8,7 +8,7 @@ use ckb_core::header::{HeaderBuilder, Seal};
 use ckb_core::script::Script;
 use ckb_core::transaction::{CellInput, CellOutput, OutPoint, Transaction, TransactionBuilder};
 use ckb_core::{capacity_bytes, BlockNumber, Bytes, Capacity};
-use jsonrpc_types::{BlockTemplate, CellbaseTemplate};
+use jsonrpc_types::{BlockTemplate, CellbaseTemplate, JsonBytes};
 use log::info;
 use numext_fixed_hash::H256;
 use rand;
@@ -355,6 +355,7 @@ impl Node {
         ckb_config.block_assembler = Some(BlockAssemblerConfig {
             code_hash: self.always_success_code_hash.clone(),
             args: Default::default(),
+            data: JsonBytes::default(),
         });
         modify_ckb_config(&mut ckb_config);
         fs::write(

test/src/specs/mining/bootstrap.rs

@@ -3,6 +3,7 @@ use ckb_app_config::{BlockAssemblerConfig, CKBAppConfig};
 use ckb_chain_spec::ChainSpec;
 use ckb_core::block::Block;
 use ckb_core::script::Script;
+use jsonrpc_types::JsonBytes;
 use log::info;
 use numext_fixed_hash::{h256, H256};
 
@@ -65,6 +66,7 @@ impl Spec for BootstrapCellbase {
             config.block_assembler = Some(BlockAssemblerConfig {
                 code_hash: h256!("0xa2"),
                 args: vec![],
+                data: JsonBytes::default(),
             });
         })
     }