Fix: [AEA-4175] - use axios-retry to retry failures (#124)

package.json

@@ -42,6 +42,7 @@
     "@aws-lambda-powertools/logger": "^2.2.0",
     "aws-lambda": "^1.0.7",
     "axios": "^1.7.2",
+    "axios-retry": "^4.4.0",
     "conventional-changelog-eslint": "^6.0.0"
   },
   "bugs": {

src/live-spine-client.ts

@@ -3,12 +3,13 @@ import {serviceHealthCheck} from "./status"
 import {SpineClient, SpineStatus} from "./spine-client"
 import {Agent} from "https"
 import axios, {
-  Axios,
   AxiosError,
+  AxiosInstance,
   AxiosRequestConfig,
   AxiosResponse
 } from "axios"
 import {APIGatewayProxyEventHeaders} from "aws-lambda"
+import axiosRetry from "axios-retry"
 
 // timeout in ms to wait for response from spine to avoid lambda timeout
 const SPINE_TIMEOUT = 45000
@@ -19,7 +20,7 @@ export class LiveSpineClient implements SpineClient {
   private readonly spineASID: string | undefined
   private readonly httpsAgent: Agent
   private readonly spinePartyKey: string | undefined
-  private readonly axiosInstance: Axios
+  private readonly axiosInstance: AxiosInstance
   private readonly logger: Logger
 
   constructor(logger: Logger) {
@@ -34,6 +35,10 @@ export class LiveSpineClient implements SpineClient {
     })
     this.logger = logger
     this.axiosInstance = axios.create()
+    axiosRetry(this.axiosInstance, {
+      retries: 3,
+      onRetry: this.onAxiosRetry
+    })
     this.axiosInstance.interceptors.request.use((config) => {
       config.headers["request-startTime"] = new Date().getTime()
       return config
@@ -164,4 +169,9 @@ export class LiveSpineClient implements SpineClient {
       process.env.SpineCAChain !== "ChangeMe"
     )
   }
+
+  onAxiosRetry = (retryCount, error) => {
+    this.logger.warn(error)
+    this.logger.warn(`Call to spine failed - retrying. Retry count ${retryCount}`)
+  }
 }

tests/live-spine-client.test.ts

@@ -104,4 +104,39 @@ describe("live spine client", () => {
     }
     await expect(spineClient.getPrescriptions(headers)).rejects.toThrow("timeout of 45000ms exceeded")
   })
+
+  test("should not throw error when one unsuccessful and one successful http request", async () => {
+    mock
+      .onGet("https://spine/mm/patientfacingprescriptions").networkErrorOnce()
+      .onGet("https://spine/mm/patientfacingprescriptions").reply(200, {resourceType: "Bundle"})
+
+    const mockLoggerWarn = jest.spyOn(Logger.prototype, "warn")
+
+    const spineClient = new LiveSpineClient(logger)
+    const headers: APIGatewayProxyEventHeaders = {
+      "nhsd-nhslogin-user": "P9:9912003071"
+    }
+    const spineResponse = await spineClient.getPrescriptions(headers)
+
+    expect(spineResponse.status).toBe(200)
+    expect(spineResponse.data).toStrictEqual({resourceType: "Bundle"})
+    expect(mockLoggerWarn).toHaveBeenCalledWith("Call to spine failed - retrying. Retry count 1")
+  })
+
+  test("should retry only 3 times when http request errors", async () => {
+    mock.onGet("https://spine/mm/patientfacingprescriptions").networkError()
+    const mockLoggerWarn = jest.spyOn(Logger.prototype, "warn")
+
+    const spineClient = new LiveSpineClient(logger)
+    const headers: APIGatewayProxyEventHeaders = {
+      "nhsd-nhslogin-user": "P9:9912003071"
+    }
+    await expect(spineClient.getPrescriptions(headers)).rejects.toThrow("Network Error")
+    expect(mockLoggerWarn).toHaveBeenCalledWith("Call to spine failed - retrying. Retry count 1")
+    expect(mockLoggerWarn).toHaveBeenCalledWith("Call to spine failed - retrying. Retry count 2")
+    expect(mockLoggerWarn).toHaveBeenCalledWith("Call to spine failed - retrying. Retry count 3")
+    expect(mockLoggerWarn).not.toHaveBeenCalledWith("Call to spine failed - retrying. Retry count 4")
+  })
+
+
 })