Generate random string in template

[miquecg]

Would it be possible to generate a random string using template functions? So far I didn't find any helper, but I've thought that maybe calling a shell function would do the trick.

$ chezmoi execute-template '{{ run "echo foo" }}'

But run and exec seem to not be available.

[halostatue]

The function you’re looking for is output: https://www.chezmoi.io/reference/templates/functions/output/

[miquecg]

Thanks for the pointer. It looks like it has some limitations though and commands cannot be piped together, or am I missing something? As a workaround I could wrap the whole thing with a script.

For the record I'm trying to achieve something like:

LC_ALL=C tr -dc A-Za-z </dev/urandom | head -c 13

[bradenhilton]

If you want to pipe within the command you need to use output "sh" "-c" "... | ...".

{{ output "sh" "-c" "LC_ALL=C tr -dc A-Za-z </dev/urandom | head -c 13" }}

[miquecg]

That's what I assumed, either everything inline or call a script.

Thanks.

[2-4601]

https://masterminds.github.io/sprig/strings.html#randalphanum-randalpha-randnumeric-and-randascii

These four functions generate cryptographically secure (uses crypto/rand) random strings, but with different base character sets:

randAlphaNum uses 0-9a-zA-Z
randAlpha uses a-zA-Z
randNumeric uses 0-9
randAscii uses all printable ASCII characters
Each of them takes one parameter: the integer length of the string.

randNumeric 3

The above will produce a random string with three digits.

$ chezmoi execute-template '{{ randAlpha 10 }}'
yAcuBuYIpo

---

https://masterminds.github.io/sprig/crypto.html#randbytes

The randBytes function accepts a count N and generates a cryptographically secure (uses crypto/rand) random sequence of N bytes. The sequence is returned as a base64 encoded string.

$ chezmoi execute-template '{{ randBytes 16 }}'
txZKVdlnWbjddmApbBTVvA==

---

https://masterminds.github.io/sprig/uuid.html#uuid-functions

Sprig can generate UUID v4 universally unique IDs.

uuidv4

The above returns a new UUID of the v4 (randomly generated) type.

$ chezmoi execute-template '{{ uuidv4 }}'
a97772b8-d001-4220-847f-36d3a80057d3

[halostatue]

Depending on the type of random value needed, this is a better overall answer.

[miquecg]

Oh, great! Didn't know about those helper functions :)