CCIP chain selectors implementation

.github/CODEOWNERS

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+*           @smartcontractkit/ccip

.github/workflows/go.yml

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+name: Go - Build and test
+
+on: [ push ]
+
+jobs:
+  build-test:
+    name: Build and test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code into the Go module directory
+        uses: actions/checkout@v2
+      - name: Set up Go
+        uses: actions/setup-go@v3
+        with:
+          go-version-file: "go.mod"
+          cache: false
+      - name: Build
+        run: go build -v ./...
+      - name: Test
+        run: go test -v ./...

.gitignore

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 # Go workspace file
 go.work
+
+
+.idea
+.vscode/
+*.iml

LICENSE

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+MIT License
+
+Copyright (c) 2023 SmartContract
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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-# ccip-chain-selectors
+# CCIP chain selectors
+
+CCIP uses its own set of chain selectors represented by uint64 to identify blockchains. This repository contains a
+mapping between the CCIP chain identifiers (`chainSelectorId`) and the chain identifiers used by the blockchains
+themselves (`chainId`).
+
+Please refer to the [official documentation](https://docs.chain.link/ccip/supported-networks) to learn more about
+supported networks and their selectors.
+
+### Installation
+
+`go get github.com/smartcontract/ccip-chain-selectors`
+
+### Usage
+
+```go
+import (
+    "github.com/smartcontractkit/ccip-chain-selectors"
+)
+
+func main() {
+    // Getting selector based on ChainId
+    selector, err := selectors.SelectorFromChainId(420)
+
+    // Getting ChainId based on ChainSelector
+    chainId, err := selectors.ChainIdFromSelector(2664363617261496610)
+
+    // Accessing mapping directly
+    lookupChainId := uint64(1337)
+    if chainSelector, exists := selectors.EvmChainIdToChainSelector()[lookupChainId]; exists {
+        fmt.Println("Found chain selector for chain", lookupChainId, ":", chainSelector)
+    }
+}
+```
+
+### Contributing
+
+Any new chains and selectors should be always added to [selectors.yml](selectors.yml) and client libraries should load
+details from this file. This ensures that all client libraries are in sync and use the same mapping.
+
+If you need a support for a new language, please open a PR with the following changes:
+- Library codebase is in a separate directory
+- Library uses selectors.yml as a source of truth
+- Proper Github workflow is present to make sure code compiles and tests pass

go.mod

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+module github.com/smartcontractkit/ccip-chain-selectors
+
+go 1.20
+
+require gopkg.in/yaml.v3 v3.0.1

go.sum

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+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

selectors.go

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+package ccip_chain_selectors
+
+import (
+	_ "embed"
+	"fmt"
+
+	"gopkg.in/yaml.v3"
+)
+
+//go:embed selectors.yml
+var selectorsYml []byte
+var evmChainIdToChainSelector = parseYml()
+
+func parseYml() map[uint64]uint64 {
+	type ymlData struct {
+		Selectors map[uint64]uint64 `yaml:"selectors"`
+	}
+
+	var data ymlData
+	err := yaml.Unmarshal(selectorsYml, &data)
+	if err != nil {
+		panic(err)
+	}
+
+	return data.Selectors
+}
+
+func EvmChainIdToChainSelector() map[uint64]uint64 {
+	copyMap := make(map[uint64]uint64, len(evmChainIdToChainSelector))
+	for k, v := range evmChainIdToChainSelector {
+		copyMap[k] = v
+	}
+	return copyMap
+}
+
+func ChainIdFromSelector(chainSelectorId uint64) (uint64, error) {
+	for k, v := range evmChainIdToChainSelector {
+		if v == chainSelectorId {
+			return k, nil
+		}
+	}
+	return 0, fmt.Errorf("chain not found for chain selector %d", chainSelectorId)
+}
+
+func SelectorFromChainId(chainId uint64) (uint64, error) {
+	if chainSelectorId, exist := evmChainIdToChainSelector[chainId]; exist {
+		return chainSelectorId, nil
+	}
+	return 0, fmt.Errorf("chain selector not found for chain %d", chainId)
+}

selectors.yml

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+selectors:
+  # Testnets
+  97: 13264668187771770619 # BSC Testnet
+  420: 2664363617261496610  # Optimism Goerli
+  1000: 11787463284727550157 # Dev network
+  1337: 3379446385462418246  # Dev network
+  2337: 12922642891491394802  # Dev network
+  43113: 14767482510784806043 # Avalanche Fuji
+  76578: 781901677223027175
+  84531: 5790810961207155433  # BASE Goerli
+  80001: 12532609583862916517 # Polygon Mumbai
+  421613: 6101244977088475029  # Arbitrum Goerli
+  11155111: 16015286601757825753 # Sepolia
+  # Mainnets
+  1: 5009297550715157269  # Ethereum
+  10: 3734403246176062136  # Optimism
+  56: 11344663589394136015 # BSC
+  137: 4051577828743386545  # Polygon
+  8453: 15971525489660198786 # BASE
+  42161: 4949039107694359620  # Arbitrum
+  43114: 6433500567565415381  # Avalanche

selectors_test.go

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+package ccip_chain_selectors
+
+import "testing"
+
+func TestEvmChainIdToChainSelectorReturningCopiedMap(t *testing.T) {
+	selectors := EvmChainIdToChainSelector()
+	selectors[1] = 2
+
+	_, err := ChainIdFromSelector(2)
+	if err == nil {
+		t.Error("Changes to map should not affect the original map")
+	}
+
+	_, err = ChainIdFromSelector(1)
+	if err == nil {
+		t.Error("Changes to map should not affect the original map")
+	}
+}
+
+func TestChainIdFromSelector(t *testing.T) {
+	_, err := ChainIdFromSelector(0)
+	if err == nil {
+		t.Error("Should return error if chain selector not found")
+	}
+
+	_, err = ChainIdFromSelector(99999999)
+	if err == nil {
+		t.Error("Should return error if chain selector not found")
+	}
+
+	chainId, err := ChainIdFromSelector(13264668187771770619)
+	if err != nil {
+		t.Error("Should return chain id if chain selector found")
+	}
+	if chainId != 97 {
+		t.Error("Should return correct chain id")
+	}
+}
+
+func TestSelectorFromChainId(t *testing.T) {
+	_, err := SelectorFromChainId(0)
+	if err == nil {
+		t.Error("Should return error if chain not found")
+	}
+
+	_, err = SelectorFromChainId(99999999)
+	if err == nil {
+		t.Error("Should return error if chain not found")
+	}
+
+	chainSelectorId, err := SelectorFromChainId(97)
+	if err != nil {
+		t.Error("Should return chain selector id if chain found")
+	}
+	if chainSelectorId != 13264668187771770619 {
+		t.Error("Should return correct chain selector id")
+	}
+}