Allow supplying a retry handler to generated API clients

oxidecomputer · Sep 20, 2024 · b582c0a · b582c0a
1 parent 7890e4d
commit b582c0a
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Showing 3 changed files with 87 additions and 4 deletions.
diff --git a/oxide-api/src/http-client.ts b/oxide-api/src/http-client.ts
@@ -117,6 +117,12 @@ export interface FullParams extends FetchParams {
   method?: string;
 }
 
+export type RetryHandler = (
+  url: RequestInfo | URL,
+  init: RequestInit,
+  err: any,
+) => boolean;
+
 export interface ApiConfig {
   /**
    * No host means requests will be sent to the current host. This is used in
@@ -125,14 +131,21 @@ export interface ApiConfig {
   host?: string;
   token?: string;
   baseParams?: FetchParams;
+  retryHandler?: RetryHandler;
 }
 
 export class HttpClient {
   host: string;
   token?: string;
   baseParams: FetchParams;
-
-  constructor({ host = "", baseParams = {}, token }: ApiConfig = {}) {
+  retryHandler: RetryHandler;
+
+  constructor({
+    host = "",
+    baseParams = {},
+    token,
+    retryHandler,
+  }: ApiConfig = {}) {
     this.host = host;
     this.token = token;
 
@@ -141,6 +154,7 @@ export class HttpClient {
       headers.append("Authorization", `Bearer ${token}`);
     }
     this.baseParams = mergeParams({ headers }, baseParams);
+    this.retryHandler = retryHandler ? retryHandler : () => false;
   }
 
   public async request<Data>({
@@ -155,7 +169,24 @@ export class HttpClient {
       ...mergeParams(this.baseParams, fetchParams),
       body: JSON.stringify(snakeify(body), replacer),
     };
+    return fetchWithRetry(fetch, url, init, this.retryHandler);
+  }
+}
+
+export async function fetchWithRetry<Data>(
+  fetch: any,
+  url: string,
+  init: RequestInit,
+  retry: RetryHandler,
+): Promise<ApiResult<Data>> {
+  try {
     return handleResponse(await fetch(url, init));
+  } catch (err) {
+    if (retry(url, init, err)) {
+      return await fetchWithRetry(fetch, url, init, retry);
+    }
+
+    throw err;
   }
 }
 

diff --git a/oxide-openapi-gen-ts/src/client/static/http-client.test.ts b/oxide-openapi-gen-ts/src/client/static/http-client.test.ts
@@ -8,7 +8,7 @@
  * Copyright Oxide Computer Company
  */
 
-import { handleResponse, mergeParams } from "./http-client";
+import { fetchWithRetry, handleResponse, mergeParams } from "./http-client";
 import { describe, expect, it } from "vitest";
 
 const headers = { "Content-Type": "application/json" };
@@ -17,6 +17,41 @@ const headers = { "Content-Type": "application/json" };
 const json = (body: any, status = 200) =>
   new Response(JSON.stringify(body), { status, headers });
 
+describe("fetchWithRetry", () => {
+  it("retries request when handler returns true", async () => {
+    const retryLimit = 1
+    let retries = 0
+    const retryHandler = () => {
+      if (retries >= retryLimit) {
+        return false
+      } else {
+        retries += 1
+        return true
+      }
+    }
+
+    try {
+      await fetchWithRetry(() => { throw new Error("unimplemented") }, "empty_url", {}, retryHandler)
+    } catch {
+      // Throw away any errors we receive, we are only interested in ensuring the retry handler
+      // gets called and that retries terminate
+    }
+
+    expect(retries).toEqual(1)
+  });
+
+  it("rethrows error when handler returns false", async () => {
+    const retryHandler = () => false
+
+    try {
+      await fetchWithRetry(() => { throw new Error("unimplemented") }, "empty_url", {}, retryHandler)
+      throw new Error("Unreachable. This is a bug")
+    } catch (err: any) {
+      expect(err.message).toEqual("unimplemented")
+    }
+  });
+});
+
 describe("handleResponse", () => {
   it("handles success", async () => {
     const { response, ...rest } = await handleResponse(json({ abc: 123 }));

diff --git a/oxide-openapi-gen-ts/src/client/static/http-client.ts b/oxide-openapi-gen-ts/src/client/static/http-client.ts
@@ -117,6 +117,8 @@ export interface FullParams extends FetchParams {
   method?: string;
 }
 
+export type RetryHandler = (url: RequestInfo | URL, init: RequestInit, err: any) => boolean;
+
 export interface ApiConfig {
   /**
    * No host means requests will be sent to the current host. This is used in
@@ -125,14 +127,16 @@ export interface ApiConfig {
   host?: string;
   token?: string;
   baseParams?: FetchParams;
+  retryHandler?: RetryHandler;
 }
 
 export class HttpClient {
   host: string;
   token?: string;
   baseParams: FetchParams;
+  retryHandler: RetryHandler;
 
-  constructor({ host = "", baseParams = {}, token }: ApiConfig = {}) {
+  constructor({ host = "", baseParams = {}, token, retryHandler }: ApiConfig = {}) {
     this.host = host;
     this.token = token;
 
@@ -141,6 +145,7 @@ export class HttpClient {
       headers.append("Authorization", `Bearer ${token}`);
     }
     this.baseParams = mergeParams({ headers }, baseParams);
+    this.retryHandler = retryHandler ? retryHandler : () => false;
   }
 
   public async request<Data>({
@@ -155,7 +160,19 @@ export class HttpClient {
       ...mergeParams(this.baseParams, fetchParams),
       body: JSON.stringify(snakeify(body), replacer),
     };
+    return fetchWithRetry(fetch, url, init, this.retryHandler)
+  }
+}
+
+export async function fetchWithRetry<Data>(fetch: any, url: string, init: RequestInit, retry: RetryHandler): Promise<ApiResult<Data>> {
+  try {
     return handleResponse(await fetch(url, init));
+  } catch (err) {
+    if (retry(url, init, err)) {
+      return await fetchWithRetry(fetch, url, init, retry)
+    }
+
+    throw err
   }
 }