Per chain rpc settings (#6459)

* ethereum, node: Per-chain RPC settings via TOML config

Introduce a ChainSettings struct that holds Ethereum RPC tuning
parameters (timeouts, retries, batch sizes, block ranges, etc.)
per chain instead of reading them from global ENV_VARS. Settings
are parsed from [chains.<name>] TOML sections with serde defaults
falling back to the existing environment variables, preserving full
backwards compatibility.

Thread ChainSettings through Chain, EthereumAdapter, and the
free receipt-fetching functions so each chain can be independently
tuned.

* docs: Document per-chain RPC settings in config and env vars

Add the full list of per-chain Ethereum RPC tuning settings to
docs/config.md with env var fallback defaults, and add a
cross-reference note in docs/environment-variables.md.

* node: Validate per-chain settings on config load

Reject invalid ChainSettings values at startup: max_block_range_size
and max_event_only_range must be positive (i32), and block_batch_size,
block_ptr_batch_size, block_ingestor_max_concurrent_json_rpc_calls,
and get_logs_max_contracts must be non-zero (used as .buffered() args
or filter batch limits where 0 would panic or silently break).

* node, docs: Address review feedback on per-chain settings

- Guard ChainSettings::validate() to Ethereum chains only
- Add zero-value validation for polling_interval, json_rpc_timeout,
  request_retries, and target_triggers_per_block_range
- Fix ETHEREUM_POLLING_INTERVAL env var name in doc comment (drop GRAPH_ prefix)
- Fix polling_interval default in docs (500ms → 1000ms)

Author: dimitrovmaksim

chain/ethereum/src/adapter.rs

@@ -364,7 +364,7 @@ pub struct EthereumLogFilter {
 
 impl From<EthereumLogFilter> for Vec<LogFilter> {
     fn from(val: EthereumLogFilter) -> Self {
-        val.eth_get_logs_filters()
+        val.eth_get_logs_filters(ENV_VARS.get_logs_max_contracts)
             .map(
                 |EthGetLogsFilter {
                      contracts,
@@ -546,7 +546,10 @@ impl EthereumLogFilter {
     /// Filters for `eth_getLogs` calls. The filters will not return false positives. This attempts
     /// to balance between having granular filters but too many calls and having few calls but too
     /// broad filters causing the Ethereum endpoint to timeout.
-    pub fn eth_get_logs_filters(self) -> impl Iterator<Item = EthGetLogsFilter> {
+    pub fn eth_get_logs_filters(
+        self,
+        get_logs_max_contracts: usize,
+    ) -> impl Iterator<Item = EthGetLogsFilter> {
         let mut filters = Vec::new();
 
         // Start with the wildcard event filters.
@@ -596,7 +599,7 @@ impl EthereumLogFilter {
             for neighbor in g.neighbors(max_vertex) {
                 match neighbor {
                     LogFilterNode::Contract(address) => {
-                        if filter.contracts.len() == ENV_VARS.get_logs_max_contracts {
+                        if filter.contracts.len() == get_logs_max_contracts {
                             // The batch size was reached, register the filter and start a new one.
                             let event = filter.event_signatures[0];
                             push_filter(filter);
@@ -1771,7 +1774,7 @@ fn complete_log_filter() {
                 wildcard_events: HashMap::new(),
                 events_with_topic_filters: HashMap::new(),
             }
-            .eth_get_logs_filters()
+            .eth_get_logs_filters(ENV_VARS.get_logs_max_contracts)
             .collect();
 
             // Assert that a contract or event is filtered on iff it was present in the graph.

chain/ethereum/src/chain.rs

@@ -68,6 +68,44 @@ use graph::blockchain::block_stream::{
 /// Celo Mainnet: 42220, Testnet Alfajores: 44787, Testnet Baklava: 62320
 const CELO_CHAIN_IDS: [u64; 3] = [42220, 44787, 62320];
 
+/// Resolved per-chain settings. Populated at chain initialisation from the config file (with
+/// ENV_VAR fallbacks) and stored on [`Chain`] and [`crate::EthereumAdapter`].
+#[derive(Clone, Debug)]
+pub struct ChainSettings {
+    pub polling_interval: Duration,
+    pub json_rpc_timeout: Duration,
+    pub request_retries: usize,
+    pub max_block_range_size: BlockNumber,
+    pub block_batch_size: usize,
+    pub block_ptr_batch_size: usize,
+    pub max_event_only_range: BlockNumber,
+    pub target_triggers_per_block_range: u64,
+    pub get_logs_max_contracts: usize,
+    pub block_ingestor_max_concurrent_json_rpc_calls: usize,
+    pub genesis_block_number: u64,
+}
+
+impl ChainSettings {
+    /// Constructs a [`ChainSettings`] from environment variable defaults.
+    /// Used in tests and for firehose-only chains that have no RPC config.
+    pub fn from_env_defaults() -> Self {
+        ChainSettings {
+            polling_interval: graph::env::ENV_VARS.ingestor_polling_interval,
+            json_rpc_timeout: ENV_VARS.json_rpc_timeout,
+            request_retries: ENV_VARS.request_retries,
+            max_block_range_size: ENV_VARS.max_block_range_size,
+            block_batch_size: ENV_VARS.block_batch_size,
+            block_ptr_batch_size: ENV_VARS.block_ptr_batch_size,
+            max_event_only_range: ENV_VARS.max_event_only_range,
+            target_triggers_per_block_range: ENV_VARS.target_triggers_per_block_range,
+            get_logs_max_contracts: ENV_VARS.get_logs_max_contracts,
+            block_ingestor_max_concurrent_json_rpc_calls: ENV_VARS
+                .block_ingestor_max_concurrent_json_rpc_calls,
+            genesis_block_number: ENV_VARS.genesis_block_number,
+        }
+    }
+}
+
 pub struct EthereumStreamBuilder {}
 
 #[async_trait]
@@ -192,9 +230,9 @@ impl BlockStreamBuilder<Chain> for EthereumStreamBuilder {
         };
 
         let max_block_range_size = if is_using_subgraph_composition {
-            ENV_VARS.max_block_range_size * 10
+            chain.settings.max_block_range_size * 10
         } else {
-            ENV_VARS.max_block_range_size
+            chain.settings.max_block_range_size
         };
 
         Ok(Box::new(PollingBlockStream::new(
@@ -206,7 +244,7 @@ impl BlockStreamBuilder<Chain> for EthereumStreamBuilder {
             reorg_threshold,
             logger,
             max_block_range_size,
-            ENV_VARS.target_triggers_per_block_range,
+            chain.settings.target_triggers_per_block_range,
             unified_api_version,
             subgraph_current_block,
         )))
@@ -325,13 +363,13 @@ pub struct Chain {
     call_cache: Arc<dyn EthereumCallCache>,
     chain_head_update_listener: Arc<dyn ChainHeadUpdateListener>,
     reorg_threshold: BlockNumber,
-    polling_ingestor_interval: Duration,
     pub is_ingestible: bool,
     block_stream_builder: Arc<dyn BlockStreamBuilder<Self>>,
     block_refetcher: Arc<dyn BlockRefetcher<Self>>,
     adapter_selector: Arc<dyn TriggersAdapterSelector<Self>>,
     runtime_adapter_builder: Arc<dyn RuntimeAdapterBuilder>,
     eth_adapters: Arc<EthereumNetworkAdapters>,
+    pub settings: Arc<ChainSettings>,
 }
 
 impl std::fmt::Debug for Chain {
@@ -388,8 +426,8 @@ impl Chain {
         runtime_adapter_builder: Arc<dyn RuntimeAdapterBuilder>,
         eth_adapters: Arc<EthereumNetworkAdapters>,
         reorg_threshold: BlockNumber,
-        polling_ingestor_interval: Duration,
         is_ingestible: bool,
+        settings: Arc<ChainSettings>,
     ) -> Self {
         Chain {
             logger_factory,
@@ -406,7 +444,7 @@ impl Chain {
             eth_adapters,
             reorg_threshold,
             is_ingestible,
-            polling_ingestor_interval,
+            settings,
         }
     }
 
@@ -637,7 +675,7 @@ impl Blockchain for Chain {
                     graph::env::ENV_VARS.reorg_threshold(),
                     self.chain_client(),
                     self.chain_store.cheap_clone(),
-                    self.polling_ingestor_interval,
+                    self.settings.polling_interval,
                     self.name.clone(),
                 )?)
             }