Terraform
filesha1 function reference
This topic provides reference information about the filesha1 function, which calculates the SHA-1 hash of a file's contents.
Introduction
The filesha1 is a variant of sha1 that hashes the contents of a given file rather than a literal string.
Use the filesha1 function instead of wrapping the file function in a sha1 function, for example sha1(file(filename)), because file accepts only UTF-8 text. As a result, you cannot use sha1(file(filename)) to create hashes for binary files.
Security warning: This hashing function is susceptible to collision attacks. Before using this function for anything security-sensitive, review relevant literature to understand the security implications.
Syntax
Use the filesha1 function with the following syntax:
filesha1(path)
The path is the relative or absolute file path to the file whose SHA-1 hash you want to compute.
In the following example, the function returns the SHA-1 value.
$ filesha1("example.txt")
d3486ae9136e7856bc42212385ea797094475802
Example use case
In the following example the filesha1 function computes the SHA-1 hash of the file example.txt located in the current module's directory. The result is a 40-character hexadecimal string representing the SHA-1 hash.
output "file_hash" {
value = filesha1("${path.module}/example.txt")
}
Related functions
sha1computes the SHA-1 hash of a given string and encodes it with hexadecimal digits.filesha256computes the SHA-256 hash of a given file and encodes it with hexadecimal digits.filesha512computes the SHA-512 hash of a given file and encodes it with hexadecimal digits.