updates bridge-relay to use API for head state (#4319)

* updates bridge-relay to use API for head state

gets head hash from '/bridge/head' if head flag is not set

posts head hash to '/bridge/head' after processing all deposits from a confirmed
block

* passes options with GET /bridge/head

options include the required token

ironfish-cli/src/commands/service/bridge/relay.ts

@@ -80,11 +80,13 @@ export default class BridgeRelay extends IronfishCommand {
 
     this.log('Watching with view key:', incomingViewKey)
 
-    // TODO: track chain state of relay in API
+    head = head ?? (await api.getBridgeHead())
+
     if (!head) {
       const chainInfo = await client.chain.getChainInfo()
       head = chainInfo.content.genesisBlockIdentifier.hash
     }
+
     this.log(`Starting from head ${head}`)
 
     const response = client.chain.getTransactionStream({
@@ -115,12 +117,12 @@ export default class BridgeRelay extends IronfishCommand {
       if (buffer.length > confirmations) {
         const response = buffer.shift()
         Assert.isNotUndefined(response)
-        this.commit(api, response)
+        await this.commit(api, response)
       }
     }
   }
 
-  commit(api: WebApi, response: GetTransactionStreamResponse): void {
+  async commit(api: WebApi, response: GetTransactionStreamResponse): Promise<void> {
     Assert.isNotUndefined(response)
 
     const transactions = response.transactions
@@ -132,5 +134,7 @@ export default class BridgeRelay extends IronfishCommand {
         // TODO: call Eth bridge contract to mint
       }
     }
+
+    await api.setBridgeHead(response.block.hash)
   }
 }

ironfish/src/webApi.ts

@@ -178,6 +178,31 @@ export class WebApi {
     await axios.post(`${this.host}/telemetry`, payload)
   }
 
+  async getBridgeHead(): Promise<string | undefined> {
+    this.requireToken()
+
+    const response = await axios
+      .get<{ hash: string }>(`${this.host}/bridge/head`, this.options())
+      .catch((e) => {
+        // The API returns 404 for no head
+        if (IsAxiosError(e) && e.response?.status === 404) {
+          return null
+        }
+
+        throw e
+      })
+
+    return response?.data.hash
+  }
+
+  async setBridgeHead(head: string): Promise<void> {
+    this.requireToken()
+
+    const options = this.options({ 'Content-Type': 'application/json' })
+
+    await axios.post(`${this.host}/bridge/head`, { head }, options)
+  }
+
   options(headers: Record<string, string> = {}): AxiosRequestConfig {
     return {
       headers: {