Rearchitecture Modules

[matifali]

We need a consistent approach to manage shell scripts within Terraform modules. Key challenges include:

1. Common Code Inclusion: Best way to include lib.sh across all modules.
2. shellcheck Validation: Ensure all scripts pass shellcheck for code quality.
3. TF Variable Access: Reliable access to Terraform variables in scripts.
4. Variable Name Conflicts: Avoid ${VAR} misusage between shell and Terraform variables.

Essentially, this is what I've come up with:

resource "coder_script" "vscode-web" {
  script = templatefile("${path.module}/script.tftpl", {
    LOADER: "/usr/bin/env bash",
    LIB: file("${path.module}/lib.sh"),
    RUN: file("${path.module}/run.sh"),
    VARS: templatefile("${path.module}/vars.tftpl", {
      PORT : var.port,
      LOG_PATH : var.log_path,
      INSTALL_PREFIX : var.install_prefix,
      EXTENSIONS : join(",", var.extensions),
      TELEMETRY_LEVEL : var.telemetry_level,
      // This is necessary otherwise the quotes are stripped!
      SETTINGS : replace(jsonencode(var.settings), "\"", "\\\""),
      OFFLINE : var.offline,
      USE_CACHED : var.use_cached,
      EXTENSIONS_DIR : var.extensions_dir,
      FOLDER : var.folder,
      AUTO_INSTALL_EXTENSIONS : var.auto_install_extensions,
    }),
  })
}

Where:

• script.tftpl is generated/based on a template
• lib.sh is copied to all modules (from e.g. .scripts/lib.sh)
• run.sh is a pure editable shell scripts, no TF variables, shellcheck and shfmt works
• vars.tftpl is autogenerated from main.tf

script.tftpl:

#!${LOADER}

# lib.sh
touch "$CODER_SCRIPT_DATA_DIR/lib.sh"
${LIB}

# vars.tftpl
touch "$CODER_SCRIPT_DATA_DIR/vars.tftpl"
${VARS}

# run.sh
${RUN}

(The touches are present here to avoid errors when executing run.sh content and sourcing the files. Alternatively the source lines could be stripped out but puts logic in main.tf.)

lib.sh:

#!/bin/sh

log() { echo "$@" }

run.sh:

#!/usr/bin/env bash

# shellcheck source=vscode-web/lib.sh
. "${CODER_SCRIPT_DATA_DIR}/lib.sh"
# shellcheck source=vscode-web/vars.tftpl
. "${CODER_SCRIPT_DATA_DIR}/vars.tftpl"

run_vscode_web() {
  log running... # log from lib.sh
  # ...

vars.tftpl:

#!/usr/bin/env sh
# Code generated by [insert name]. DO NOT EDIT.

# shellcheck disable=SC2269
PORT="${PORT}" # type: number, default: 13338, description: The port to run VS Code Web on.
LOG_PATH="${LOG_PATH}" # ...
INSTALL_PREFIX="${INSTALL_PREFIX}"
EXTENSIONS="${EXTENSIONS}"
TELEMETRY_LEVEL="${TELEMETRY_LEVEL}"
SETTINGS="${SETTINGS}"
OFFLINE="${OFFLINE}"
USE_CACHED="${USE_CACHED}"
EXTENSIONS_DIR="${EXTENSIONS_DIR}"
FOLDER="${FOLDER}"
AUTO_INSTALL_EXTENSIONS="${AUTO_INSTALL_EXTENSIONS}"

End result (coder script):

#!/usr/bin/env bash

# lib.sh
touch "$CODER_SCRIPT_DATA_DIR/lib.sh"
#!/bin/sh

log() { echo "$@" }

# vars.tftpl
touch "$CODER_SCRIPT_DATA_DIR/vars.tftpl"
#!/usr/bin/env sh
# Code generated by [insert name]. DO NOT EDIT.

# shellcheck disable=SC2269
PORT="${PORT}" # type: number, default: 13338, description: The port to run VS Code Web on.
LOG_PATH="${LOG_PATH}" # ...
INSTALL_PREFIX="${INSTALL_PREFIX}"
EXTENSIONS="${EXTENSIONS}"
TELEMETRY_LEVEL="${TELEMETRY_LEVEL}"
SETTINGS="${SETTINGS}"
OFFLINE="${OFFLINE}"
USE_CACHED="${USE_CACHED}"
EXTENSIONS_DIR="${EXTENSIONS_DIR}"
FOLDER="${FOLDER}"
AUTO_INSTALL_EXTENSIONS="${AUTO_INSTALL_EXTENSIONS}"

# run.sh
#!/usr/bin/env bash

# shellcheck source=vscode-web/lib.sh
. "${CODER_SCRIPT_DATA_DIR}/lib.sh"
# shellcheck source=vscode-web/vars.tftpl
. "${CODER_SCRIPT_DATA_DIR}/vars.tftpl"

run_vscode_web() {
  log running... # log from lib.sh
  # ...

---

Not sure if this will make it hard to understand the project structure and how/where to contribute. I have some other ideas too, but that requires introducing a pre-filter for shellcheck and supporting shfmt would be hard. Also you'd still have to be careful with $${VAR} vs ${VAR} but we could introduce a new linter for that and enforce that all tf is at the top of the file, for instance.

Also, it'd be possible to combine script.tftpl and vars.tftpl if that makes things easier, but at the same time it'd be a bit of inception (run.sh imports script.tftpl and script.tftpl embeds run.sh)

Originally posted by @mafredri in #331