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digest.sha256

The digest.sha256 function returns the SHA-256 digest of a string as lowercase hexadecimal. Pair it with fs.read_file to fingerprint an artifact, compare a build against a published copy, or derive a cache key from file contents.

Usage​

digest.sha256(data)

Arguments​

data

Required. The string to hash. Strings are byte strings, so the contents of a binary file returned by fs.read_file hash exactly as the bytes on disk, and text hashes as its UTF-8 encoding.

Returns​

The digest as a 64-character lowercase hexadecimal string.

Examples​

Fingerprint a build artifact​

artifact_sha256 = digest.sha256(fs.read_file(".build/handler.zip"))
ci.output("artifact_sha256", artifact_sha256)

Confirm two builds are byte-identical​

first = digest.sha256(fs.read_file("dist/v1/app.zip"))
again = digest.sha256(fs.read_file("dist/v1-rebuild/app.zip"))
if first != again:
    fail("the rebuild is not reproducible")

Derive a cache key from inputs​

key = "deps-" + digest.sha256(fs.read_file("go.sum"))[:16]

Errors​

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

Related​