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digest.md5

The digest.md5 function returns the MD5 digest of a string as lowercase hexadecimal. MD5 is not collision resistant, so use it only where another system already expects it, such as comparing against a compatible S3 ETag. For fingerprints you control, use digest.sha256.

Usage​

digest.md5(data)

Arguments​

data
Required. The string to hash, as bytes.

Returns​

The digest as a 32-character lowercase hexadecimal string.

Example​

Compare a local file with an S3 ETag​

This comparison applies to single-part S3 uploads that are unencrypted or use SSE-S3. SSE-KMS, SSE-C, and multipart uploads do not have MD5 ETags; use an explicit S3 checksum for those objects.

local = digest.md5(fs.read_file(".build/handler.zip"))
etag = exec.run(["aws", "s3api", "head-object", "--bucket", bucket, "--key", key], output = "capture").data["ETag"].strip('"')
if local != etag:
    fail("the published object differs from the local build")

Errors​

  • A missing argument, or an argument that is not a string, fails with an argument error.

Related​