Merge pull request #3063 from nkomonen-amazon/samPythonError

feat(sam): collect sam cli errors

Author: nkomonen-amazon

src/shared/sam/cli/samCliInvokerUtils.ts

@@ -55,6 +55,47 @@ export function logAndThrowIfUnexpectedExitCode(processResult: ChildProcessResul
             message = processResult.error.message
         }
     }
+    const usefulErrors = collectAcceptedErrorMessages(processResult.stderr).join('\n')
+    throw makeUnexpectedExitCodeError(message ?? usefulErrors)
+}
+
+/**
+ * Collect known errors messages from a sam error message
+ * that may have multiple errors in one message.
+ * @param errors A string that can have multiple error messages
+ */
+export function collectAcceptedErrorMessages(errorMessage: string): string[] {
+    const errors = errorMessage.split('\n')
+    const shouldCollectFuncs = [startsWithEscapeSequence, startsWithError]
+    return errors.filter(error => {
+        return shouldCollectFuncs.some(shouldCollect => {
+            return shouldCollect(error)
+        })
+    })
+}
+
+/**
+ * All accepted escape sequences.
+ */
+const yellowForeground = '[33m'
+const acceptedSequences = [yellowForeground]
+
+/**
+ * Returns true if text starts with an escape
+ * sequence with one of the accepted sequences.
+ */
+function startsWithEscapeSequence(text: string, sequences = acceptedSequences): boolean {
+    const escapeInDecimal = 27
+    if (text.charCodeAt(0) !== escapeInDecimal) {
+        return false
+    }
+
+    const remainingText = text.substring(1)
+    return sequences.some(code => {
+        return remainingText.startsWith(code)
+    })
+}
 
-    throw makeUnexpectedExitCodeError(message ?? 'no message available')
+function startsWithError(text: string): boolean {
+    return text.startsWith('Error:')
 }

src/test/shared/sam/cli/samCliInvokerUtils.test.ts

@@ -5,6 +5,7 @@
 
 import * as assert from 'assert'
 import {
+    collectAcceptedErrorMessages,
     logAndThrowIfUnexpectedExitCode,
     makeUnexpectedExitCodeError,
 } from '../../../../shared/sam/cli/samCliInvokerUtils'
@@ -42,3 +43,41 @@ describe('logAndThrowIfUnexpectedExitCode', async function () {
         await assertLogContainsBadExitInformation(getTestLogger(), childProcessResult, 456)
     })
 })
+
+/**
+ * Returns a string with the 'Escape' character
+ * prepended to the given text.
+ *
+ * This exists because using '\e' does not
+ * work.
+ */
+function prependEscapeCode(text: string): string {
+    return String.fromCharCode(27) + text
+}
+
+describe('collectAcceptedErrorMessages()', async () => {
+    let result: string[]
+
+    before(async () => {
+        const input = [
+            prependEscapeCode('[33m This is an accepted escape sequence'),
+            prependEscapeCode('[100m This is not an accepted escape sequence'),
+            'This will be ignored',
+            'Error: This is accepted due to the prefix',
+        ].join('\n')
+        result = collectAcceptedErrorMessages(input)
+    })
+
+    it('has the expected amount of messages', async () => {
+        assert.strictEqual(result.length, 2)
+    })
+    it('collects the "Error:" prefix', async () => {
+        assert(result.includes('Error: This is accepted due to the prefix'))
+    })
+    it('collects accepted escape sequence prefixes', async () => {
+        assert(result.includes(prependEscapeCode('[33m This is an accepted escape sequence')))
+    })
+    it('ignores non-accepted escape sequence prefixes', async () => {
+        assert(!result.includes(prependEscapeCode('[100m This is not an accepted escape sequence')))
+    })
+})