feat: support multiple REST URIs

README.md

@@ -90,7 +90,10 @@ Create a `config.json` file with the following structure:
       "bech32Prefix": "init",
       "chainId": "chain-2",
       "gasPrice": "0umin",
-      "restUri": "https://rest.chain-2.com",
+      "restUri": [
+        "https://rest.chain-2.com",
+        "https://rest.chain-2.com/fallback"
+      ],
       "rpcUri": ["https://rpc.chain-2.com", "https://rpc.chain-2.com/fallback"],
       "wallets": [
         {
@@ -129,7 +132,7 @@ You can configure chains in two ways:
    - `CHAIN_<index>_CHAIN_ID`: Chain ID for the chain at index `<index>`
    - `CHAIN_<index>_BECH32_PREFIX`: Bech32 prefix for the chain
    - `CHAIN_<index>_GAS_PRICE`: Gas price for the chain
-   - `CHAIN_<index>_REST_URI`: REST URI for the chain
+   - `CHAIN_<index>_REST_URI`: REST URI for the chain (can be a single URI string or JSON array of URI strings)
    - `CHAIN_<index>_RPC_URI`: RPC URI for the chain (can be a single URI string or array of URI strings)
    - `CHAIN_<index>_FEE_FILTER`: JSON string containing the fee filter configuration
 
@@ -182,7 +185,7 @@ export CHAIN_0_FEE_FILTER='{"recvFee":[{"denom":"gas","amount":100}],"timeoutFee
 export CHAIN_1_CHAIN_ID=chain-2
 export CHAIN_1_BECH32_PREFIX=init
 export CHAIN_1_GAS_PRICE=0umin
-export CHAIN_1_REST_URI=https://rest.chain-2.com
+export CHAIN_1_REST_URI='["https://rest.chain-2.com", "https://rest-fallback.chain-2.com"]'  # JSON array of URI strings for fallback
 export CHAIN_1_RPC_URI='["https://rpc.chain-2.com", "https://rpc-fallback.chain-2.com"]'  # JSON array of URI strings for fallback
 
 # Chain 2 wallet 1 configuration

config.example.json

@@ -50,7 +50,10 @@
       "bech32Prefix": "init",
       "chainId": "chain-2",
       "gasPrice": "0umin",
-      "restUri": "https://rest.chain-2.com",
+      "restUri": [
+        "https://rest.chain-2.com",
+        "https://rest.chain-2.com/fallback"
+      ],
       "rpcUri": "https://rpc.chain-2.com",
       "wallets": [
         {

config.schema.json

@@ -121,8 +121,18 @@
             "description": "gas price in format 0.1denom"
           },
           "restUri": {
-            "type": "string",
-            "description": "cosmos rest api uri"
+            "description": "cosmos rest api uri",
+            "oneOf": [
+              {
+                "type": "string"
+              },
+              {
+                "type": "array",
+                "items": {
+                  "type": "string"
+                }
+              }
+            ]
           },
           "rpcUri": {
             "description": "cosmos rest rpc uri",

src/lib/config.spec.ts

@@ -170,6 +170,43 @@ describe('Configuration Loading', () => {
       ])
     })
 
+    it('should parse REST URI as array when formatted as JSON array', () => {
+      process.env.CHAIN_1_CHAIN_ID = 'test-chain-1'
+      process.env.CHAIN_1_BECH32_PREFIX = 'test'
+      process.env.CHAIN_1_GAS_PRICE = '0.01'
+      process.env.CHAIN_1_REST_URI =
+        '["http://localhost:1317", "http://localhost:1318"]'
+      process.env.CHAIN_1_RPC_URI = 'http://localhost:26657'
+
+      // Setup wallet env vars
+      process.env.CHAIN_1_WALLET_1_KEY_TYPE = 'raw'
+      process.env.CHAIN_1_WALLET_1_KEY_PRIVATE_KEY = 'testkey'
+
+      const config = loadEnvConfig()
+
+      expect(config.chains?.[0].restUri).toEqual([
+        'http://localhost:1317',
+        'http://localhost:1318',
+      ])
+    })
+
+    it.each(['["http://localhost:1317",]', '[]', '[""]', '[123]'])(
+      'should reject invalid URI arrays: %s',
+      (uriArray) => {
+        process.env.CHAIN_1_CHAIN_ID = 'test-chain-1'
+        process.env.CHAIN_1_BECH32_PREFIX = 'test'
+        process.env.CHAIN_1_GAS_PRICE = '0.01'
+        process.env.CHAIN_1_REST_URI = uriArray
+        process.env.CHAIN_1_RPC_URI = 'http://localhost:26657'
+
+        // Setup wallet env vars
+        process.env.CHAIN_1_WALLET_1_KEY_TYPE = 'raw'
+        process.env.CHAIN_1_WALLET_1_KEY_PRIVATE_KEY = 'testkey'
+
+        expect(() => loadEnvConfig()).toThrow(/URI array/)
+      }
+    )
+
     it('should parse fee filter from env vars', () => {
       const feeFilter: PacketFee = {
         recvFee: [{ denom: 'token', amount: 100 }],

src/lib/config.ts

@@ -31,6 +31,31 @@ export const safeJsonParse = <T>(json: string, defaultValue: T): T => {
   }
 }
 
+const parseUriConfig = (rawUri: string): string | string[] => {
+  const trimmedUri = rawUri.trim()
+
+  if (trimmedUri.startsWith('[') && trimmedUri.endsWith(']')) {
+    let parsed: unknown
+    try {
+      parsed = JSON.parse(trimmedUri)
+    } catch (err) {
+      throw new Error(`Invalid URI array JSON: ${err}`)
+    }
+
+    if (
+      !Array.isArray(parsed) ||
+      parsed.length === 0 ||
+      parsed.some((uri) => typeof uri !== 'string' || uri.trim() === '')
+    ) {
+      throw new Error('URI array must contain at least one non-empty string')
+    }
+
+    return parsed.map((uri) => uri.trim())
+  }
+
+  return trimmedUri
+}
+
 // load configuration from environment variables
 export const loadEnvConfig = (): Partial<Config> => {
   const envConfig: Partial<Config> = {}
@@ -79,16 +104,15 @@ export const loadEnvConfig = (): Partial<Config> => {
         chain.bech32Prefix = env[`CHAIN_${index}_BECH32_PREFIX`]
       if (env[`CHAIN_${index}_GAS_PRICE`])
         chain.gasPrice = env[`CHAIN_${index}_GAS_PRICE`]
-      if (env[`CHAIN_${index}_REST_URI`])
-        chain.restUri = env[`CHAIN_${index}_REST_URI`]
+
+      const rawRestUri = env[`CHAIN_${index}_REST_URI`]?.trim()
+      if (rawRestUri) {
+        chain.restUri = parseUriConfig(rawRestUri)
+      }
 
       const rawRpcUri = env[`CHAIN_${index}_RPC_URI`]?.trim()
       if (rawRpcUri) {
-        if (rawRpcUri.startsWith('[') && rawRpcUri.endsWith(']')) {
-          chain.rpcUri = safeJsonParse<string[]>(rawRpcUri, [rawRpcUri])
-        } else {
-          chain.rpcUri = rawRpcUri
-        }
+        chain.rpcUri = parseUriConfig(rawRpcUri)
       }
 
       // fee filter
@@ -331,7 +355,7 @@ interface ChainConfig {
   bech32Prefix: string
   chainId: string
   gasPrice: string
-  restUri: string
+  restUri: string | string[]
   rpcUri: string | string[]
   wallets: WalletConfig[]
   feeFilter?: PacketFee

src/lib/restClient.spec.ts

@@ -0,0 +1,84 @@
+import nock from 'nock'
+import { RESTClient } from './restClient'
+import { logger } from './logger'
+
+const mockRestUris = [
+  'http://doi-rest-1.com',
+  'http://moro-rest-2.com',
+  'http://rene-rest-3.com',
+]
+
+describe('RESTClient', () => {
+  afterEach(() => {
+    nock.cleanAll()
+    jest.restoreAllMocks()
+  })
+
+  it('should use the first endpoint successfully', async () => {
+    nock(mockRestUris[0]).get('/cosmos/base/node/v1beta1/config').reply(200, {
+      minimum_gas_price: '0.01uinit',
+    })
+
+    const client = new RESTClient(mockRestUris)
+    const result = await client.apiRequester.get<{ minimum_gas_price: string }>(
+      '/cosmos/base/node/v1beta1/config'
+    )
+
+    expect(result.minimum_gas_price).toBe('0.01uinit')
+  })
+
+  it('should fallback to the next endpoint if the first one fails', async () => {
+    nock(mockRestUris[0]).get('/cosmos/base/node/v1beta1/config').reply(500)
+    nock(mockRestUris[1]).get('/cosmos/base/node/v1beta1/config').reply(200, {
+      minimum_gas_price: '0.02uinit',
+    })
+
+    const loggerSpy = jest.spyOn(logger, 'error')
+    const client = new RESTClient(mockRestUris)
+    const result = await client.apiRequester.get<{ minimum_gas_price: string }>(
+      '/cosmos/base/node/v1beta1/config'
+    )
+
+    expect(result.minimum_gas_price).toBe('0.02uinit')
+    expect(loggerSpy).toHaveBeenCalledWith(
+      expect.stringContaining(
+        `[REST] Failed to request to ${mockRestUris[0]} - /cosmos/base/node/v1beta1/config`
+      )
+    )
+  })
+
+  it('should not fallback on client errors', async () => {
+    nock(mockRestUris[0]).get('/cosmos/base/node/v1beta1/config').reply(404)
+    const fallback = nock(mockRestUris[1])
+      .get('/cosmos/base/node/v1beta1/config')
+      .reply(200, {
+        minimum_gas_price: '0.02uinit',
+      })
+
+    const client = new RESTClient(mockRestUris)
+
+    await expect(
+      client.apiRequester.get('/cosmos/base/node/v1beta1/config')
+    ).rejects.toThrow()
+    expect(fallback.isDone()).toBe(false)
+  })
+
+  it('should prefer the last successful endpoint for later requests', async () => {
+    nock(mockRestUris[0]).get('/cosmos/base/node/v1beta1/config').reply(500)
+    nock(mockRestUris[1]).get('/cosmos/base/node/v1beta1/config').reply(200, {
+      minimum_gas_price: '0.02uinit',
+    })
+    nock(mockRestUris[1]).get('/cosmos/base/node/v1beta1/config').reply(200, {
+      minimum_gas_price: '0.03uinit',
+    })
+
+    const client = new RESTClient(mockRestUris)
+
+    await client.apiRequester.get('/cosmos/base/node/v1beta1/config')
+    const result = await client.apiRequester.get<{ minimum_gas_price: string }>(
+      '/cosmos/base/node/v1beta1/config'
+    )
+
+    expect(result.minimum_gas_price).toBe('0.03uinit')
+  })
+})