Merge pull request #26 from vulcanize/canonical_hash_finder

update canonical header finder functions

db/migrations/00018_create_check_if_removed_functions.sql

@@ -3,7 +3,7 @@
 -- returns if a storage node at the provided path was removed in the range > the provided height and <= the provided block hash
 CREATE OR REPLACE FUNCTION was_storage_removed(path BYTEA, height BIGINT, hash VARCHAR(66)) RETURNS BOOLEAN
 AS $$
-  SELECT exists(SELECT *
+  SELECT exists(SELECT 1
 					FROM eth.storage_cids
             INNER JOIN eth.state_cids ON (storage_cids.state_id = state_cids.id)
             INNER JOIN eth.header_cids ON (state_cids.header_id = header_cids.id)
@@ -12,7 +12,8 @@ AS $$
 					AND block_number <= (SELECT block_number
 										FROM eth.header_cids
 										WHERE block_hash = hash)
-					AND storage_cids.node_type = 3);
+					AND storage_cids.node_type = 3
+					LIMIT 1);
 $$ LANGUAGE SQL;
 -- +goose StatementEnd
 
@@ -20,7 +21,7 @@ $$ LANGUAGE SQL;
 -- returns if a state node at the provided path was removed in the range > the provided height and <= the provided block hash
 CREATE OR REPLACE FUNCTION was_state_removed(path BYTEA, height BIGINT, hash VARCHAR(66)) RETURNS BOOLEAN
 AS $$
-  SELECT exists(SELECT *
+  SELECT exists(SELECT 1
 					FROM eth.state_cids
             INNER JOIN eth.header_cids ON (state_cids.header_id = header_cids.id)
 					WHERE state_path = path
@@ -28,7 +29,8 @@ AS $$
 					AND block_number <= (SELECT block_number
 										FROM eth.header_cids
 										WHERE block_hash = hash)
-					AND state_cids.node_type = 3);
+					AND state_cids.node_type = 3
+					LIMIT 1);
 $$ LANGUAGE SQL;
 -- +goose StatementEnd
 

db/migrations/00019_updated_canonical_hash_finder_functions.sql

@@ -0,0 +1,121 @@
+-- +goose Up
+-- +goose StatementBegin
+CREATE TYPE child_result AS (
+  has_child BOOLEAN,
+  children eth.header_cids[]
+);
+
+CREATE OR REPLACE FUNCTION has_child(hash VARCHAR(66), height BIGINT) RETURNS child_result AS
+$BODY$
+DECLARE
+  child_height INT;
+  temp_child eth.header_cids;
+  new_child_result child_result;
+BEGIN
+  child_height = height + 1;
+  -- short circuit if there are no children
+  SELECT exists(SELECT 1
+                FROM eth.header_cids
+                WHERE parent_hash = hash
+                AND block_number = child_height
+                LIMIT 1)
+  INTO new_child_result.has_child;
+  -- collect all the children for this header
+  IF new_child_result.has_child THEN
+    FOR temp_child IN
+      SELECT * FROM eth.header_cids WHERE parent_hash = hash AND block_number = child_height
+    LOOP
+      new_child_result.children = array_append(new_child_result.children, temp_child);
+    END LOOP;
+  END IF;
+  RETURN new_child_result;
+END
+$BODY$
+LANGUAGE 'plpgsql';
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+CREATE OR REPLACE FUNCTION canonical_header_from_array(headers eth.header_cids[]) RETURNS eth.header_cids AS
+$BODY$
+DECLARE
+  canonical_header eth.header_cids;
+  canonical_child eth.header_cids;
+  header eth.header_cids;
+  current_child_result child_result;
+  child_headers eth.header_cids[];
+  current_header_with_child eth.header_cids;
+  has_children_count INT DEFAULT 0;
+BEGIN
+  -- for each header in the provided set
+  FOREACH header IN ARRAY headers
+  LOOP
+    -- check if it has any children
+    current_child_result = has_child(header.block_hash, header.block_number);
+    IF current_child_result.has_child THEN
+      -- if it does, take note
+      has_children_count = has_children_count + 1;
+      current_header_with_child = header;
+      -- and add the children to the growing set of child headers
+      child_headers = array_cat(child_headers, current_child_result.children);
+    END IF;
+  END LOOP;
+  -- if none of the headers had children, none is more canonical than the other
+  IF has_children_count = 0 THEN
+    -- return the first one selected
+    SELECT * INTO canonical_header FROM unnest(headers) LIMIT 1;
+  -- if only one header had children, it can be considered the heaviest/canonical header of the set
+  ELSIF has_children_count = 1 THEN
+    -- return the only header with a child
+    canonical_header = current_header_with_child;
+  -- if there are multiple headers with children
+  ELSE
+    -- find the canonical header from the child set
+    canonical_child = canonical_header_from_array(child_headers);
+    -- the header that is parent to this header, is the canonical header at this level
+    SELECT * INTO canonical_header FROM unnest(headers)
+    WHERE block_hash = canonical_child.parent_hash;
+  END IF;
+  RETURN canonical_header;
+END
+$BODY$
+LANGUAGE 'plpgsql';
+-- +goose StatementEnd
+
+-- +goose StatementBegin
+CREATE OR REPLACE FUNCTION canonical_header_id(height BIGINT) RETURNS INTEGER AS
+$BODY$
+DECLARE
+  canonical_header eth.header_cids;
+  headers eth.header_cids[];
+  header_count INT;
+  temp_header eth.header_cids;
+BEGIN
+  -- collect all headers at this height
+  FOR temp_header IN
+    SELECT * FROM eth.header_cids WHERE block_number = height
+  LOOP
+    headers = array_append(headers, temp_header);
+  END LOOP;
+  -- count the number of headers collected
+  header_count = array_length(headers, 1);
+  -- if we have less than 1 header, return NULL
+  IF header_count IS NULL OR header_count < 1 THEN
+    RETURN NULL;
+  -- if we have one header, return its id
+  ELSIF header_count = 1 THEN
+    RETURN headers[1].id;
+  -- if we have multiple headers we need to determine which one is canonical
+  ELSE
+    canonical_header = canonical_header_from_array(headers);
+    RETURN canonical_header.id;
+  END IF;
+END;
+$BODY$
+LANGUAGE 'plpgsql';
+-- +goose StatementEnd
+
+-- +goose Down
+DROP FUNCTION canonical_header_id;
+DROP FUNCTION canonical_header_from_array;
+DROP FUNCTION has_child;
+DROP TYPE child_result;

db/schema.sql

@@ -2,8 +2,8 @@
 -- PostgreSQL database dump
 --
 
--- Dumped from database version 12.1
+-- Dumped from database version 12.4
--- Dumped by pg_dump version 12.1
+-- Dumped by pg_dump version 12.4
 
 SET statement_timeout = 0;
 SET lock_timeout = 0;
@@ -23,6 +23,58 @@ SET row_security = off;
 CREATE SCHEMA eth;
 
 
+SET default_tablespace = '';
+
+SET default_table_access_method = heap;
+
+--
+-- Name: header_cids; Type: TABLE; Schema: eth; Owner: -
+--
+
+CREATE TABLE eth.header_cids (
+    id integer NOT NULL,
+    block_number bigint NOT NULL,
+    block_hash character varying(66) NOT NULL,
+    parent_hash character varying(66) NOT NULL,
+    cid text NOT NULL,
+    mh_key text NOT NULL,
+    td numeric NOT NULL,
+    node_id integer NOT NULL,
+    reward numeric NOT NULL,
+    state_root character varying(66) NOT NULL,
+    tx_root character varying(66) NOT NULL,
+    receipt_root character varying(66) NOT NULL,
+    uncle_root character varying(66) NOT NULL,
+    bloom bytea NOT NULL,
+    "timestamp" numeric NOT NULL,
+    times_validated integer DEFAULT 1 NOT NULL
+);
+
+
+--
+-- Name: TABLE header_cids; Type: COMMENT; Schema: eth; Owner: -
+--
+
+COMMENT ON TABLE eth.header_cids IS '@name EthHeaderCids';
+
+
+--
+-- Name: COLUMN header_cids.node_id; Type: COMMENT; Schema: eth; Owner: -
+--
+
+COMMENT ON COLUMN eth.header_cids.node_id IS '@name EthNodeID';
+
+
+--
+-- Name: child_result; Type: TYPE; Schema: public; Owner: -
+--
+
+CREATE TYPE public.child_result AS (
+	has_child boolean,
+	children eth.header_cids[]
+);
+
+
 --
 -- Name: graphql_subscription(); Type: FUNCTION; Schema: eth; Owner: -
 --
@@ -78,6 +130,125 @@ END
 $$;
 
 
+--
+-- Name: canonical_header_from_array(eth.header_cids[]); Type: FUNCTION; Schema: public; Owner: -
+--
+
+CREATE FUNCTION public.canonical_header_from_array(headers eth.header_cids[]) RETURNS eth.header_cids
+    LANGUAGE plpgsql
+    AS $$
+DECLARE
+  canonical_header eth.header_cids;
+  canonical_child eth.header_cids;
+  header eth.header_cids;
+  current_child_result child_result;
+  child_headers eth.header_cids[];
+  current_header_with_child eth.header_cids;
+  has_children_count INT DEFAULT 0;
+BEGIN
+  -- for each header in the provided set
+  FOREACH header IN ARRAY headers
+  LOOP
+    -- check if it has any children
+    current_child_result = has_child(header.block_hash, header.block_number);
+    IF current_child_result.has_child THEN
+      -- if it does, take note
+      has_children_count = has_children_count + 1;
+      current_header_with_child = header;
+      -- and add the children to the growing set of child headers
+      child_headers = array_cat(child_headers, current_child_result.children);
+    END IF;
+  END LOOP;
+  -- if none of the headers had children, none is more canonical than the other
+  IF has_children_count = 0 THEN
+    -- return the first one selected
+    SELECT * INTO canonical_header FROM unnest(headers) LIMIT 1;
+  -- if only one header had children, it can be considered the heaviest/canonical header of the set
+  ELSIF has_children_count = 1 THEN
+    -- return the only header with a child
+    canonical_header = current_header_with_child;
+  -- if there are multiple headers with children
+  ELSE
+    -- find the canonical header from the child set
+    canonical_child = canonical_header_from_array(child_headers);
+    -- the header that is parent to this header, is the canonical header at this level
+    SELECT * INTO canonical_header FROM unnest(headers)
+    WHERE block_hash = canonical_child.parent_hash;
+  END IF;
+  RETURN canonical_header;
+END
+$$;
+
+
+--
+-- Name: canonical_header_id(bigint); Type: FUNCTION; Schema: public; Owner: -
+--
+
+CREATE FUNCTION public.canonical_header_id(height bigint) RETURNS integer
+    LANGUAGE plpgsql
+    AS $$
+DECLARE
+  canonical_header eth.header_cids;
+  headers eth.header_cids[];
+  header_count INT;
+  temp_header eth.header_cids;
+BEGIN
+  -- collect all headers at this height
+  FOR temp_header IN
+    SELECT * FROM eth.header_cids WHERE block_number = height
+  LOOP
+    headers = array_append(headers, temp_header);
+  END LOOP;
+  -- count the number of headers collected
+  header_count = array_length(headers, 1);
+  -- if we have less than 1 header, return NULL
+  IF header_count IS NULL OR header_count < 1 THEN
+    RETURN NULL;
+  -- if we have one header, return its id
+  ELSIF header_count = 1 THEN
+    RETURN headers[1].id;
+  -- if we have multiple headers we need to determine which one is canonical
+  ELSE
+    canonical_header = canonical_header_from_array(headers);
+    RETURN canonical_header.id;
+  END IF;
+END;
+$$;
+
+
+--
+-- Name: has_child(character varying, bigint); Type: FUNCTION; Schema: public; Owner: -
+--
+
+CREATE FUNCTION public.has_child(hash character varying, height bigint) RETURNS public.child_result
+    LANGUAGE plpgsql
+    AS $$
+DECLARE
+  child_height INT;
+  temp_child eth.header_cids;
+  new_child_result child_result;
+BEGIN
+  child_height = height + 1;
+  -- short circuit if there are no children
+  SELECT exists(SELECT 1
+                FROM eth.header_cids
+                WHERE parent_hash = hash
+                AND block_number = child_height
+                LIMIT 1)
+  INTO new_child_result.has_child;
+  -- collect all the children for this header
+  IF new_child_result.has_child THEN
+    FOR temp_child IN
+      SELECT * FROM eth.header_cids WHERE parent_hash = hash AND block_number = child_height
+    LOOP
+      new_child_result.children = array_append(new_child_result.children, temp_child);
+    END LOOP;
+  END IF;
+  RETURN new_child_result;
+END
+$$;
+
+
 --
 -- Name: header_weight(character varying); Type: FUNCTION; Schema: public; Owner: -
 --
@@ -107,7 +278,7 @@ $$;
 CREATE FUNCTION public.was_state_removed(path bytea, height bigint, hash character varying) RETURNS boolean
     LANGUAGE sql
     AS $$
-  SELECT exists(SELECT *
+  SELECT exists(SELECT 1
 					FROM eth.state_cids
             INNER JOIN eth.header_cids ON (state_cids.header_id = header_cids.id)
 					WHERE state_path = path
@@ -115,7 +286,8 @@ CREATE FUNCTION public.was_state_removed(path bytea, height bigint, hash charact
 					AND block_number <= (SELECT block_number
 										FROM eth.header_cids
 										WHERE block_hash = hash)
-					AND state_cids.node_type = 3);
+					AND state_cids.node_type = 3
+					LIMIT 1);
 $$;
 
 
@@ -126,7 +298,7 @@ $$;
 CREATE FUNCTION public.was_storage_removed(path bytea, height bigint, hash character varying) RETURNS boolean
     LANGUAGE sql
     AS $$
-  SELECT exists(SELECT *
+  SELECT exists(SELECT 1
 					FROM eth.storage_cids
             INNER JOIN eth.state_cids ON (storage_cids.state_id = state_cids.id)
             INNER JOIN eth.header_cids ON (state_cids.header_id = header_cids.id)
@@ -135,52 +307,11 @@ CREATE FUNCTION public.was_storage_removed(path bytea, height bigint, hash chara
 					AND block_number <= (SELECT block_number
 										FROM eth.header_cids
 										WHERE block_hash = hash)
-					AND storage_cids.node_type = 3);
+					AND storage_cids.node_type = 3
+					LIMIT 1);
 $$;
 
 
-SET default_tablespace = '';
-
-SET default_table_access_method = heap;
-
---
--- Name: header_cids; Type: TABLE; Schema: eth; Owner: -
---
-
-CREATE TABLE eth.header_cids (
-    id integer NOT NULL,
-    block_number bigint NOT NULL,
-    block_hash character varying(66) NOT NULL,
-    parent_hash character varying(66) NOT NULL,
-    cid text NOT NULL,
-    mh_key text NOT NULL,
-    td numeric NOT NULL,
-    node_id integer NOT NULL,
-    reward numeric NOT NULL,
-    state_root character varying(66) NOT NULL,
-    tx_root character varying(66) NOT NULL,
-    receipt_root character varying(66) NOT NULL,
-    uncle_root character varying(66) NOT NULL,
-    bloom bytea NOT NULL,
-    "timestamp" numeric NOT NULL,
-    times_validated integer DEFAULT 1 NOT NULL
-);
-
-
---
--- Name: TABLE header_cids; Type: COMMENT; Schema: eth; Owner: -
---
-
-COMMENT ON TABLE eth.header_cids IS '@name EthHeaderCids';
-
-
---
--- Name: COLUMN header_cids.node_id; Type: COMMENT; Schema: eth; Owner: -
---
-
-COMMENT ON COLUMN eth.header_cids.node_id IS '@name EthNodeID';
-
-
 --
 -- Name: header_cids_id_seq; Type: SEQUENCE; Schema: eth; Owner: -
 --

pkg/eth/backend.go

@@ -55,10 +55,10 @@ var (
 const (
 	RetrieveCanonicalBlockHashByNumber = `SELECT block_hash FROM eth.header_cids
 									INNER JOIN public.blocks ON (header_cids.mh_key = blocks.key)
-									WHERE id = (SELECT canonical_header($1))`
+									WHERE id = (SELECT canonical_header_id($1))`
 	RetrieveCanonicalHeaderByNumber = `SELECT cid, data FROM eth.header_cids
 									INNER JOIN public.blocks ON (header_cids.mh_key = blocks.key)
-									WHERE id = (SELECT canonical_header($1))`
+									WHERE id = (SELECT canonical_header_id($1))`
 	RetrieveTD = `SELECT td FROM eth.header_cids
 			WHERE header_cids.block_hash = $1`
 	RetrieveRPCTransaction = `SELECT blocks.data, block_hash, block_number, index FROM public.blocks, eth.transaction_cids, eth.header_cids
@@ -72,7 +72,7 @@ const (
 											AND block_number <= (SELECT block_number
 																FROM eth.header_cids
 																WHERE block_hash = $2)
-											AND header_cids.id = (SELECT canonical_header(block_number))
+											AND header_cids.id = (SELECT canonical_header_id(block_number))
 											ORDER BY block_number DESC
 											LIMIT 1`
 	RetrieveCodeByMhKey = `SELECT data FROM public.blocks WHERE key = $1`

pkg/eth/eth_state_test.go

@@ -61,14 +61,15 @@ func init() {
 
 var _ = Describe("eth state reading tests", func() {
 	var (
-		blocks      []*types.Block
+		blocks                  []*types.Block
-		receipts    []types.Receipts
+		receipts                []types.Receipts
-		chain       *core.BlockChain
+		chain                   *core.BlockChain
-		db          *postgres.DB
+		db                      *postgres.DB
-		api         *eth.PublicEthAPI
+		api                     *eth.PublicEthAPI
-		backend     *eth.Backend
+		backend                 *eth.Backend
-		chainConfig = params.TestChainConfig
+		chainConfig             = params.TestChainConfig
-		mockTD      = big.NewInt(1337)
+		mockTD                  = big.NewInt(1337)
+		expectedCanonicalHeader map[string]interface{}
 	)
 	It("test init", func() {
 		// db and type initializations
@@ -90,6 +91,27 @@ var _ = Describe("eth state reading tests", func() {
 			IntermediateStateNodes:   true,
 			IntermediateStorageNodes: true,
 		}
+		canonicalHeader := blocks[1].Header()
+		expectedCanonicalHeader = map[string]interface{}{
+			"number":           (*hexutil.Big)(canonicalHeader.Number),
+			"hash":             canonicalHeader.Hash(),
+			"parentHash":       canonicalHeader.ParentHash,
+			"nonce":            canonicalHeader.Nonce,
+			"mixHash":          canonicalHeader.MixDigest,
+			"sha3Uncles":       canonicalHeader.UncleHash,
+			"logsBloom":        canonicalHeader.Bloom,
+			"stateRoot":        canonicalHeader.Root,
+			"miner":            canonicalHeader.Coinbase,
+			"difficulty":       (*hexutil.Big)(canonicalHeader.Difficulty),
+			"extraData":        hexutil.Bytes([]byte{}),
+			"size":             hexutil.Uint64(canonicalHeader.Size()),
+			"gasLimit":         hexutil.Uint64(canonicalHeader.GasLimit),
+			"gasUsed":          hexutil.Uint64(canonicalHeader.GasUsed),
+			"timestamp":        hexutil.Uint64(canonicalHeader.Time),
+			"transactionsRoot": canonicalHeader.TxHash,
+			"receiptsRoot":     canonicalHeader.ReceiptHash,
+			"totalDifficulty":  (*hexutil.Big)(mockTD),
+		}
 		// iterate over the blocks, generating statediff payloads, and transforming the data into Postgres
 		builder := statediff.NewBuilder(chain.StateCache())
 		for i, block := range blocks {
@@ -128,6 +150,17 @@ var _ = Describe("eth state reading tests", func() {
 			_, err = transformer.Transform(0, payload)
 			Expect(err).ToNot(HaveOccurred())
 		}
+
+		// Insert some non-canonical data into the database so that we test our ability to discern canonicity
+		indexAndPublisher := eth2.NewIPLDPublisher(db)
+		api = eth.NewPublicEthAPI(backend, nil)
+		err = indexAndPublisher.Publish(test_helpers.MockConvertedPayload)
+		Expect(err).ToNot(HaveOccurred())
+		// The non-canonical header has a child
+		err = indexAndPublisher.Publish(test_helpers.MockConvertedPayloadForChild)
+		Expect(err).ToNot(HaveOccurred())
+		err = publishCode(db, test_helpers.ContractCodeHash, test_helpers.ContractCode)
+		Expect(err).ToNot(HaveOccurred())
 	})
 	defer It("test teardown", func() {
 		eth.TearDownDB(db)
@@ -423,4 +456,12 @@ var _ = Describe("eth state reading tests", func() {
 			Expect(val).To(Equal(hexutil.Bytes{}))
 		})
 	})
+
+	Describe("eth_getHeaderByNumber", func() {
+		It("Finds the canonical header based on the header's weight relative to others at the provided height", func() {
+			header, err := api.GetHeaderByNumber(ctx, number)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(header).To(Equal(expectedCanonicalHeader))
+		})
+	})
 })

pkg/eth/ipld_retriever.go

@@ -108,7 +108,7 @@ const (
 												AND block_number <= (SELECT block_number
 																	FROM eth.header_cids
 																	WHERE block_hash = $2)
-												AND header_cids.id = (SELECT canonical_header(block_number))
+												AND header_cids.id = (SELECT canonical_header_id(block_number))
 												ORDER BY block_number DESC
 												LIMIT 1`
 	RetrieveAccountByLeafKeyAndBlockNumberPgStr = `SELECT state_cids.cid,
@@ -151,7 +151,7 @@ const (
 																	AND block_number <= (SELECT block_number
 																						FROM eth.header_cids
 																						WHERE block_hash = $3)
-																	AND header_cids.id = (SELECT canonical_header(block_number))
+																	AND header_cids.id = (SELECT canonical_header_id(block_number))
 																	ORDER BY block_number DESC
 																	LIMIT 1`
 )

pkg/eth/test_helpers/test_data.go

@@ -77,9 +77,21 @@ var (
 			Extra:       []byte{},
 		},
 	}
-	ReceiptsRlp, _       = rlp.EncodeToBytes(MockReceipts)
+	ReceiptsRlp, _   = rlp.EncodeToBytes(MockReceipts)
-	MockBlock            = types.NewBlock(&MockHeader, MockTransactions, MockUncles, MockReceipts)
+	MockBlock        = types.NewBlock(&MockHeader, MockTransactions, MockUncles, MockReceipts)
-	MockHeaderRlp, _     = rlp.EncodeToBytes(MockBlock.Header())
+	MockHeaderRlp, _ = rlp.EncodeToBytes(MockBlock.Header())
+	MockChildHeader  = types.Header{
+		Time:        0,
+		Number:      new(big.Int).Add(BlockNumber, common.Big1),
+		Root:        common.HexToHash("0x0"),
+		TxHash:      common.HexToHash("0x0"),
+		ReceiptHash: common.HexToHash("0x0"),
+		Difficulty:  big.NewInt(5000001),
+		Extra:       []byte{},
+		ParentHash:  MockBlock.Header().Hash(),
+	}
+	MockChild            = types.NewBlock(&MockChildHeader, MockTransactions, MockUncles, MockReceipts)
+	MockChildRlp, _      = rlp.EncodeToBytes(MockChild.Header())
 	Address              = common.HexToAddress("0xaE9BEa628c4Ce503DcFD7E305CaB4e29E7476592")
 	AnotherAddress       = common.HexToAddress("0xaE9BEa628c4Ce503DcFD7E305CaB4e29E7476593")
 	ContractAddress      = crypto.CreateAddress(SenderAddr, MockTransactions[2].Nonce())
@@ -351,6 +363,15 @@ var (
 		StorageNodes:    MockStorageNodes,
 		StateNodes:      MockStateNodes,
 	}
+	MockConvertedPayloadForChild = eth.ConvertedPayload{
+		TotalDifficulty: MockChild.Difficulty(),
+		Block:           MockChild,
+		Receipts:        MockReceipts,
+		TxMetaData:      MockTrxMeta,
+		ReceiptMetaData: MockRctMeta,
+		StorageNodes:    MockStorageNodes,
+		StateNodes:      MockStateNodes,
+	}
 
 	MockCIDWrapper = &eth2.CIDWrapper{
 		BlockNumber: new(big.Int).Set(BlockNumber),

pkg/rpc/check.go

@@ -1,3 +1,19 @@
+// VulcanizeDB
+// Copyright © 2020 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 package rpc
 
 import "github.com/ethereum/go-ethereum/rpc"

pkg/rpc/http.go

@@ -1,3 +1,19 @@
+// VulcanizeDB
+// Copyright © 2020 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 package rpc
 
 import (

pkg/rpc/ipc.go

@@ -1,3 +1,19 @@
+// VulcanizeDB
+// Copyright © 2020 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 package rpc
 
 import (

pkg/rpc/ws.go

@@ -1,3 +1,19 @@
+// VulcanizeDB
+// Copyright © 2020 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
 package rpc
 
 import (