Enables specifying channels in the build configuration to automatically update existing HCP Packer registry channels to point to the new build version upon completion. Improves workflow automation and reduces manual channel management for users.
This update adds a new section explaining conditional expressions in HCL, including syntax, usage examples, and best practices for clarity and maintainability. The documentation covers how to use conditionals for default values, dynamic argument omission, and recommends using locals for complex logic.
Ref: #12806
Signed-off-by: Ryan Johnson <[email protected]>
This commit adds 3 new HCL2 functions:
* `sum`: computes the sum of a collection of numerical values
* `startswith`: checks if a string has another as prefix
* `endswith`: checks if a string has another as suffix
# Description
The output of the example on [uuidv4 Function](https://developer.hashicorp.com/packer/docs/templates/hcl_templates/functions/uuid/uuidv4) is not a valid RFC compliant UUIDv4. It indicates the usage of the `uuidv4()` function and outputs `b5ee72a3-54dd-c4b8-551c-4bdc0204cedb` which is not a valid UUIDv4.
I've corrected the example to output a UUIDv4 conforming to the RFC as such `xxxxxxxx-xxxx-4xxx-Nxxx-xxxxxxxxxxxx`, where:
- The 13th character is always `4` (indicating version 4).
- The 17th character must be either `8`, `9`, `a`, or `b` (indicating the first character of the variant).
# Changes
```diff
- b5ee72a3-54dd-c4b8-551c-4bdc0204cedb
+ 9fc99a70-7cd5-482d-bb2b-03af016e4e94
```
Replaces the old UUID output with a valid RFC compliant UUIDv4.
# References
- [RFC 4122](https://datatracker.ietf.org/doc/html/rfc4122)
- [RFC 9562](https://datatracker.ietf.org/doc/html/rfc9562)
# Misc.
To make sure this wasn't an issue with the `uuidv4()` function within Hashicorp's [packer](https://github.com/hashicorp/packer) I tested the function in the following way:
### Command executed:
```ps
> .\packer.exe inspect .\uuid.pkr.hcl
```
### Contents of the _uuid.pkr.hcl_ file:
```hcl
locals {
uuid_0 = uuidv4()
uuid_1 = uuidv4()
uuid_2 = uuidv4()
uuid_3 = uuidv4()
uuid_4 = uuidv4()
uuid_5 = uuidv4()
uuid_6 = uuidv4()
uuid_7 = uuidv4()
uuid_8 = uuidv4()
uuid_9 = uuidv4()
}
```
### Output:
```ps
Packer Inspect: HCL2 mode
> input-variables:
> local-variables:
local.uuid_0: "90877db8-5519-46ea-ae15-7dfb92594064"
local.uuid_1: "fe6a4649-97d9-4686-b981-3295175f941a"
local.uuid_2: "9944d83d-dab2-4cfb-a1db-572d19271e7a"
local.uuid_3: "547cddb7-c979-4b87-90d0-2bd9b68858b5"
local.uuid_4: "c13dc47a-552c-4dfb-a75d-2f63bb248b41"
local.uuid_5: "3db1ce29-bdde-4642-b010-1a41d47c22a3"
local.uuid_6: "4a020460-edd1-471d-b8a2-5956c0c68257"
local.uuid_7: "1845bf87-6908-4fc0-8f11-b5b4f36c60a7"
local.uuid_8: "f5c7e552-b799-45f3-8172-46162eadfd89"
local.uuid_9: "057c2eaf-6769-4a8d-90c8-775aec80496a"
> builds:
```
Adds an example of a string template being used.
The example demonstrates how a template sequence can be used to embed the value of a variable into a string that can be used as script content.
Ref: #12651
Signed-off-by: Ryan Johnson <[email protected]>
Compared to Terraform, Packer was lacking a capability to encode/decode
strings to/from base64-encoded text encoded with another encoding.
This could be problematic in some cases, mainly when working with
Windows, as most of the OS uses UTF-16LE as its standard encoding for
many operations.
Therefore, we take a page from Terraform here, and add those functions
to what Packer supports in an HCL2 context.
The HCL2 docs on built-in functions contains a link to a non-existent
section of the expressions page, so we update it to link to the general
page, and to the string interpolation section, since it is a common use
case.
Tanmay Jain
Leah Bush
Ryan Johnson
Nick Philbrook
karthik P
trujillo-adam
Joban
Martin Grogan
Gregory Bonk
Wenfeng Pan
Ryan Johnson
Wilken Rivera
pavedroad
Devashish
ygXXII
Kévin Dunglas