From 4296eba6143fd58477ddd077ca9efa714c9403af Mon Sep 17 00:00:00 2001
From: "Michael Barney, Jr" <mbarneyme@gmail.com>
Date: Tue, 14 May 2024 15:36:17 -0400
Subject: [PATCH] feat(cfn): use exponential backoff with jitter for cfn api
 calls

---
 CHANGELOG.md |  6 ++++++
 flake.lock   | 27 +++++++++++++++++++++++++++
 flake.nix    | 28 ++++++++++++++++++++++++++++
 index.mjs    | 27 ++++++++++++++++++++-------
 package.json |  2 +-
 5 files changed, 82 insertions(+), 8 deletions(-)
 create mode 100644 flake.lock
 create mode 100644 flake.nix

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c9b6cdd..7065627 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # cfn-changeset-viewer
 
+## 0.0.5
+
+### Patch Changes
+
+- add exponential backoff to cfn api call
+
 ## 0.0.4
 
 ### Patch Changes
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..501f0a7
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1715691446,
+        "narHash": "sha256-4UUvzMzEKkyhmj+iu5wD4RiZz6hjOJyqbHea3y3HyKs=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "6c7da9d305628d92202eb475048129cb86a89e9d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-23.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..ec91bf8
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,28 @@
+{
+  description = "cfn-changeset-viewer";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/release-23.11";
+  };
+  outputs = { nixpkgs, ... }:
+    let
+      shell = { system }:
+        let
+          pkgs = import nixpkgs {
+            system = system;
+          };
+        in
+        pkgs.mkShell {
+          buildInputs = [
+            pkgs.awscli2
+            pkgs.nodejs_20
+          ];
+        };
+    in
+    {
+      devShells.aarch64-darwin.default = shell { system = "aarch64-darwin"; };
+      devShells.x86_64-darwin.default = shell { system = "x86_64-darwin"; };
+      devShells.aarch64-linux.default = shell { system = "aarch64-linux"; };
+      devShells.x86_64-linux.default = shell { system = "x86_64-linux"; };
+    };
+}
diff --git a/index.mjs b/index.mjs
index bcaa705..76cafc8 100755
--- a/index.mjs
+++ b/index.mjs
@@ -41,13 +41,26 @@ async function printChangeSet(changeSetId, stackName, path, showUnchangedPropert
     Dynamic: 0,
   };
   if (!path) path = "";
-  const response = await cfn.send(
-    new DescribeChangeSetCommand({
-      ChangeSetName: changeSetId,
-      StackName: stackName,
-      IncludePropertyValues: true,
-    }),
-  );
+  let response;
+  let attempts = 0;
+
+  while (!response) {
+    try {
+      response = await cfn.send(
+        new DescribeChangeSetCommand({
+          ChangeSetName: changeSetId,
+          StackName: stackName,
+          IncludePropertyValues: true,
+        }),
+      );
+    } catch (err) {
+      if (!(err instanceof Error)) throw err;
+      if (err.name !== "Throttling") throw err;
+      if (attempts++ > 5) throw err;
+      // exponential backoff sleep with jitter
+      await new Promise((resolve) => setTimeout(resolve, 2 ** attempts * 1000 + Math.random() * 1000));
+    }
+  }
 
   for (let change of response.Changes ?? []) {
     const resourceChange = change.ResourceChange;
diff --git a/package.json b/package.json
index ae4bb97..c47431b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "cfn-changeset-viewer",
-  "version": "0.0.4",
+  "version": "0.0.5",
   "description": "View the details of a CloudFormation ChangeSet (including nested ones!) in a human-friendly way",
   "main": "index.mjs",
   "type": "module",