chore: add logging for CredentialsProviderError

.changeset/two-weeks-provide.md

@@ -0,0 +1,6 @@
+---
+"@smithy/node-config-provider": patch
+"@smithy/property-provider": patch
+---
+
+add logging capability for CredentialsProviderError

packages/node-config-provider/src/fromEnv.ts

@@ -1,6 +1,8 @@
 import { CredentialsProviderError } from "@smithy/property-provider";
 import { Provider } from "@smithy/types";
 
+import { getSelectorName } from "./getSelectorName";
+
 // Using Record<string, string | undefined> instead of NodeJS.ProcessEnv, in order to not get type errors in non node environments
 export type GetterFromEnv<T> = (env: Record<string, string | undefined>) => T | undefined;
 
@@ -19,7 +21,7 @@ export const fromEnv =
       return config as T;
     } catch (e) {
       throw new CredentialsProviderError(
-        e.message || `Cannot load config from environment variables with getter: ${envVarSelector}`
+        e.message || `Not found in ENV: ${getSelectorName(envVarSelector.toString())}`
       );
     }
   };

packages/node-config-provider/src/fromSharedConfigFiles.ts

@@ -2,6 +2,8 @@ import { CredentialsProviderError } from "@smithy/property-provider";
 import { getProfileName, loadSharedConfigFiles, SourceProfileInit } from "@smithy/shared-ini-file-loader";
 import { ParsedIniData, Profile, Provider } from "@smithy/types";
 
+import { getSelectorName } from "./getSelectorName";
+
 export interface SharedConfigInit extends SourceProfileInit {
   /**
    * The preferred shared ini file to load the config. "config" option refers to
@@ -41,8 +43,7 @@ export const fromSharedConfigFiles =
       return configValue;
     } catch (e) {
       throw new CredentialsProviderError(
-        e.message ||
-          `Cannot load config for profile ${profile} in SDK configuration files with getter: ${configSelector}`
+        e.message || `Not found in config files w/ profile [${profile}]: ${getSelectorName(configSelector.toString())}`
       );
     }
   };

packages/node-config-provider/src/getSelectorName.ts

@@ -0,0 +1,15 @@
+/**
+ * Attempts to extract the name of the variable that the functional selector is looking for.
+ * Improves readability over the raw Function.toString() value.
+ *
+ * @param functionString - function's string representation.
+ *
+ * @returns constant value used within the function.
+ */
+export function getSelectorName(functionString: string): string {
+  const constants = new Set(Array.from(functionString.match(/([A-Z_]){3,}/g) ?? []));
+  constants.delete("CONFIG");
+  constants.delete("CONFIG_PREFIX_SEPARATOR");
+  constants.delete("ENV");
+  return [...constants].join(", ");
+}

packages/property-provider/src/CredentialsProviderError.spec.ts

@@ -2,10 +2,24 @@ import { CredentialsProviderError } from "./CredentialsProviderError";
 import { ProviderError } from "./ProviderError";
 
 describe(CredentialsProviderError.name, () => {
+  afterAll(() => {
+    CredentialsProviderError.logLimit = 100;
+  });
+
   it("should be named as CredentialsProviderError", () => {
     expect(new CredentialsProviderError("PANIC").name).toBe("CredentialsProviderError");
   });
 
+  it("should log up to its logLimit", () => {
+    CredentialsProviderError.logLimit = 5;
+
+    Array.from({ length: CredentialsProviderError.logLimit + 2 }).forEach(() => {
+      new CredentialsProviderError("PANIC");
+    });
+
+    expect(CredentialsProviderError.log.length).toEqual(CredentialsProviderError.logLimit);
+  });
+
   describe.each([Error, ProviderError, CredentialsProviderError])("should be instanceof %p", (classConstructor) => {
     it("when created using constructor", () => {
       expect(new CredentialsProviderError("PANIC")).toBeInstanceOf(classConstructor);

packages/property-provider/src/CredentialsProviderError.ts

@@ -12,13 +12,18 @@ import { ProviderError } from "./ProviderError";
  * ensures the chain will stop if an entirely unexpected error is encountered.
  */
 export class CredentialsProviderError extends ProviderError {
-  name = "CredentialsProviderError";
-  constructor(
+  public static log: string[] = [];
+  public static logLimit = 100;
+  public name = "CredentialsProviderError";
+  public constructor(
     message: string,
     public readonly tryNextLink: boolean = true
   ) {
     super(message, tryNextLink);
-    // Remove once we stop targetting ES5.
     Object.setPrototypeOf(this, CredentialsProviderError.prototype);
+    CredentialsProviderError.log.push(`${new Date().toISOString()} ${tryNextLink ? "->" : "(!)"} ${message}`);
+    while (CredentialsProviderError.log.length > CredentialsProviderError.logLimit) {
+      CredentialsProviderError.log.shift();
+    }
   }
 }