feat(coder/modules/agent-helper): add agent-helper module to help run scripts (#704)

## Description
The Agent Helper module is a building block for modules that need to run
multiple scripts in a specific order. It uses `coder exp sync` for
dependency management and is designed for orchestrating pre-install,
install, post-install, and start scripts.

## Type of Change

- [x] New module
- [ ] New template
- [ ] Bug fix
- [ ] Feature/enhancement
- [ ] Documentation
- [ ] Other

## Module Information

<!-- Delete this section if not applicable -->

**Path:** `registry/coder/modules/agent-helper`  
**New version:** `v1.0.0`  
**Breaking change:** [x] Yes [ ] No

## Testing & Validation

- [x] Tests pass (`bun test`)
- [x] Code formatted (`bun fmt`)
- [x] Changes tested locally

## Related Issues

Closes: https://github.com/coder/registry/issues/696
Closes: https://github.com/coder/registry/issues/698

---------

Co-authored-by: DevCats <christofer@coder.com>

registry/coder/modules/agent-helper/README.md

@@ -0,0 +1,65 @@
+---
+display_name: Agent Helper
+description: Building block for modules that need orchestrated script execution
+icon: ../../../../.icons/coder.svg
+verified: false
+tags: [internal, library]
+---
+
+# Agent Helper
+
+> [!CAUTION]
+> We do not recommend using this module directly. It is intended primarily for internal use by Coder to create modules with orchestrated script execution.
+
+The Agent Helper module is a building block for modules that need to run multiple scripts in a specific order. It uses `coder exp sync` for dependency management and is designed for orchestrating pre-install, install, post-install, and start scripts.
+
+> [!NOTE]
+>
+> - The `agent_name` should be the same as that of the agentapi module's `agent_name` if used together.
+
+```tf
+module "agent_helper" {
+  source  = "registry.coder.com/coder/agent-helper/coder"
+  version = "1.0.0"
+
+  agent_id        = coder_agent.main.id
+  agent_name      = "myagent"
+  module_dir_name = ".my-module"
+
+  pre_install_script = <<-EOT
+    #!/bin/bash
+    echo "Running pre-install tasks..."
+    # Your pre-install logic here
+  EOT
+
+  install_script = <<-EOT
+    #!/bin/bash
+    echo "Installing dependencies..."
+    # Your install logic here
+  EOT
+
+  post_install_script = <<-EOT
+    #!/bin/bash
+    echo "Running post-install configuration..."
+    # Your post-install logic here
+  EOT
+
+  start_script = <<-EOT
+    #!/bin/bash
+    echo "Starting the application..."
+    # Your start logic here
+  EOT
+}
+```
+
+## Execution Order
+
+The module orchestrates scripts in the following order:
+
+1. **Log File Creation** - Creates module directory and log files
+2. **Pre-Install Script** (optional) - Runs before installation
+3. **Install Script** - Main installation
+4. **Post-Install Script** (optional) - Runs after installation
+5. **Start Script** - Starts the application
+
+Each script waits for its prerequisites to complete before running using `coder exp sync` dependency management.

registry/coder/modules/agent-helper/main.test.ts

@@ -0,0 +1,13 @@
+import { describe } from "bun:test";
+import { runTerraformInit, testRequiredVariables } from "~test";
+
+describe("agent-helper", async () => {
+  await runTerraformInit(import.meta.dir);
+
+  testRequiredVariables(import.meta.dir, {
+    agent_id: "test-agent-id",
+    agent_name: "test-agent",
+    module_dir_name: ".test-module",
+    start_script: "echo 'start'",
+  });
+});

registry/coder/modules/agent-helper/main.tf

@@ -0,0 +1,190 @@
+terraform {
+  required_version = ">= 1.0"
+
+  required_providers {
+    coder = {
+      source  = "coder/coder"
+      version = ">= 2.13"
+    }
+  }
+}
+
+variable "agent_id" {
+  type        = string
+  description = "The ID of a Coder agent."
+}
+
+data "coder_workspace" "me" {}
+
+data "coder_workspace_owner" "me" {}
+
+data "coder_task" "me" {}
+
+variable "pre_install_script" {
+  type        = string
+  description = "Custom script to run before installing the agent used by AgentAPI."
+  default     = null
+}
+
+variable "install_script" {
+  type        = string
+  description = "Script to install the agent used by AgentAPI."
+  default     = null
+}
+
+variable "post_install_script" {
+  type        = string
+  description = "Custom script to run after installing the agent used by AgentAPI."
+  default     = null
+}
+
+variable "start_script" {
+  type        = string
+  description = "Script that starts AgentAPI."
+}
+
+variable "agent_name" {
+  type        = string
+  description = "The name of the agent. This is used to construct unique script names for the experiment sync."
+
+}
+
+variable "module_dir_name" {
+  type        = string
+  description = "The name of the module directory."
+}
+
+locals {
+  encoded_pre_install_script  = var.pre_install_script != null ? base64encode(var.pre_install_script) : ""
+  encoded_install_script      = var.install_script != null ? base64encode(var.install_script) : ""
+  encoded_post_install_script = var.post_install_script != null ? base64encode(var.post_install_script) : ""
+  encoded_start_script        = base64encode(var.start_script)
+
+  pre_install_script_name  = "${var.agent_name}-pre_install_script"
+  install_script_name      = "${var.agent_name}-install_script"
+  post_install_script_name = "${var.agent_name}-post_install_script"
+  start_script_name        = "${var.agent_name}-start_script"
+
+  module_dir_path = "$HOME/${var.module_dir_name}"
+
+  pre_install_path  = "${local.module_dir_path}/pre_install.sh"
+  install_path      = "${local.module_dir_path}/install.sh"
+  post_install_path = "${local.module_dir_path}/post_install.sh"
+  start_path        = "${local.module_dir_path}/start.sh"
+
+  pre_install_log_path  = "${local.module_dir_path}/pre_install.log"
+  install_log_path      = "${local.module_dir_path}/install.log"
+  post_install_log_path = "${local.module_dir_path}/post_install.log"
+  start_log_path        = "${local.module_dir_path}/start.log"
+}
+
+resource "coder_script" "pre_install_script" {
+  count        = var.pre_install_script == null ? 0 : 1
+  agent_id     = var.agent_id
+  display_name = "Pre-Install Script"
+  run_on_start = true
+  script       = <<-EOT
+    #!/bin/bash
+    set -o errexit
+    set -o pipefail
+
+    mkdir -p ${local.module_dir_path}
+
+    trap 'coder exp sync complete ${local.pre_install_script_name}' EXIT
+    coder exp sync start ${local.pre_install_script_name}
+
+    echo -n '${local.encoded_pre_install_script}' | base64 -d > ${local.pre_install_path}
+    chmod +x ${local.pre_install_path}
+
+    ${local.pre_install_path} > ${local.pre_install_log_path} 2>&1
+  EOT
+}
+
+resource "coder_script" "install_script" {
+  agent_id     = var.agent_id
+  display_name = "Install Script"
+  run_on_start = true
+  script       = <<-EOT
+    #!/bin/bash
+    set -o errexit
+    set -o pipefail
+
+    mkdir -p ${local.module_dir_path}
+
+    trap 'coder exp sync complete ${local.install_script_name}' EXIT
+    %{if var.pre_install_script != null~}
+      coder exp sync want ${local.install_script_name} ${local.pre_install_script_name}
+    %{endif~}
+    coder exp sync start ${local.install_script_name}
+    echo -n '${local.encoded_install_script}' | base64 -d > ${local.install_path}
+    chmod +x ${local.install_path}
+
+    ${local.install_path} > ${local.install_log_path} 2>&1
+  EOT
+}
+
+resource "coder_script" "post_install_script" {
+  count        = var.post_install_script != null ? 1 : 0
+  agent_id     = var.agent_id
+  display_name = "Post-Install Script"
+  run_on_start = true
+  script       = <<-EOT
+    #!/bin/bash
+    set -o errexit
+    set -o pipefail
+
+    trap 'coder exp sync complete ${local.post_install_script_name}' EXIT
+    coder exp sync want ${local.post_install_script_name} ${local.install_script_name}
+    coder exp sync start ${local.post_install_script_name}
+
+    echo -n '${local.encoded_post_install_script}' | base64 -d > ${local.post_install_path}
+    chmod +x ${local.post_install_path}
+
+    ${local.post_install_path} > ${local.post_install_log_path} 2>&1
+  EOT
+}
+
+resource "coder_script" "start_script" {
+  agent_id     = var.agent_id
+  display_name = "Start Script"
+  run_on_start = true
+  script       = <<-EOT
+    #!/bin/bash
+    set -o errexit
+    set -o pipefail
+
+    trap 'coder exp sync complete ${local.start_script_name}' EXIT
+
+    %{if var.post_install_script != null~}
+    coder exp sync want ${local.start_script_name} ${local.install_script_name} ${local.post_install_script_name}
+    %{else~}
+    coder exp sync want ${local.start_script_name} ${local.install_script_name}
+    %{endif~}
+    coder exp sync start ${local.start_script_name}
+
+    echo -n '${local.encoded_start_script}' | base64 -d > ${local.start_path}
+    chmod +x ${local.start_path}
+
+    ${local.start_path} > ${local.start_log_path} 2>&1
+  EOT
+}
+
+output "pre_install_script_name" {
+  description = "The name of the pre-install script for sync."
+  value       = local.pre_install_script_name
+}
+
+output "install_script_name" {
+  description = "The name of the install script for sync."
+  value       = local.install_script_name
+}
+
+output "post_install_script_name" {
+  description = "The name of the post-install script for sync."
+  value       = local.post_install_script_name
+}
+
+output "start_script_name" {
+  description = "The name of the start script for sync."
+  value       = local.start_script_name
+}

registry/coder/modules/agent-helper/main.tftest.hcl

@@ -0,0 +1,271 @@
+# Test for agent-helper module
+
+# Test with all scripts provided
+run "test_with_all_scripts" {
+  command = plan
+
+  variables {
+    agent_id            = "test-agent-id"
+    agent_name          = "test-agent"
+    module_dir_name     = ".test-module"
+    pre_install_script  = "echo 'pre-install'"
+    install_script      = "echo 'install'"
+    post_install_script = "echo 'post-install'"
+    start_script        = "echo 'start'"
+  }
+
+  # Verify pre_install_script is created when provided
+  assert {
+    condition     = length(coder_script.pre_install_script) == 1
+    error_message = "Pre-install script should be created when pre_install_script is provided"
+  }
+
+  assert {
+    condition     = coder_script.pre_install_script[0].agent_id == "test-agent-id"
+    error_message = "Pre-install script agent ID should match input"
+  }
+
+  assert {
+    condition     = coder_script.pre_install_script[0].display_name == "Pre-Install Script"
+    error_message = "Pre-install script should have correct display name"
+  }
+
+  assert {
+    condition     = coder_script.pre_install_script[0].run_on_start == true
+    error_message = "Pre-install script should run on start"
+  }
+
+  # Verify install_script is created
+  assert {
+    condition     = coder_script.install_script.agent_id == "test-agent-id"
+    error_message = "Install script agent ID should match input"
+  }
+
+  assert {
+    condition     = coder_script.install_script.display_name == "Install Script"
+    error_message = "Install script should have correct display name"
+  }
+
+  assert {
+    condition     = coder_script.install_script.run_on_start == true
+    error_message = "Install script should run on start"
+  }
+
+  # Verify post_install_script is created when provided
+  assert {
+    condition     = length(coder_script.post_install_script) == 1
+    error_message = "Post-install script should be created when post_install_script is provided"
+  }
+
+  assert {
+    condition     = coder_script.post_install_script[0].agent_id == "test-agent-id"
+    error_message = "Post-install script agent ID should match input"
+  }
+
+  assert {
+    condition     = coder_script.post_install_script[0].display_name == "Post-Install Script"
+    error_message = "Post-install script should have correct display name"
+  }
+
+  assert {
+    condition     = coder_script.post_install_script[0].run_on_start == true
+    error_message = "Post-install script should run on start"
+  }
+
+  # Verify start_script is created
+  assert {
+    condition     = coder_script.start_script.agent_id == "test-agent-id"
+    error_message = "Start script agent ID should match input"
+  }
+
+  assert {
+    condition     = coder_script.start_script.display_name == "Start Script"
+    error_message = "Start script should have correct display name"
+  }
+
+  assert {
+    condition     = coder_script.start_script.run_on_start == true
+    error_message = "Start script should run on start"
+  }
+
+  # Verify outputs for script names
+  assert {
+    condition     = output.pre_install_script_name == "test-agent-pre_install_script"
+    error_message = "Pre-install script name output should be correctly formatted"
+  }
+
+  assert {
+    condition     = output.install_script_name == "test-agent-install_script"
+    error_message = "Install script name output should be correctly formatted"
+  }
+
+  assert {
+    condition     = output.post_install_script_name == "test-agent-post_install_script"
+    error_message = "Post-install script name output should be correctly formatted"
+  }
+
+  assert {
+    condition     = output.start_script_name == "test-agent-start_script"
+    error_message = "Start script name output should be correctly formatted"
+  }
+}
+
+# Test with only required scripts (no pre/post install)
+run "test_without_optional_scripts" {
+  command = plan
+
+  variables {
+    agent_id        = "test-agent-id"
+    agent_name      = "test-agent"
+    module_dir_name = ".test-module"
+    install_script  = "echo 'install'"
+    start_script    = "echo 'start'"
+  }
+
+  # Verify pre_install_script is NOT created when not provided
+  assert {
+    condition     = length(coder_script.pre_install_script) == 0
+    error_message = "Pre-install script should not be created when pre_install_script is null"
+  }
+
+  # Verify post_install_script is NOT created when not provided
+  assert {
+    condition     = length(coder_script.post_install_script) == 0
+    error_message = "Post-install script should not be created when post_install_script is null"
+  }
+
+  # Verify required scripts are still created
+  assert {
+    condition     = coder_script.install_script.agent_id == "test-agent-id"
+    error_message = "Install script should be created"
+  }
+
+  assert {
+    condition     = coder_script.start_script.agent_id == "test-agent-id"
+    error_message = "Start script should be created"
+  }
+
+  # Verify outputs
+  assert {
+    condition     = output.pre_install_script_name == "test-agent-pre_install_script"
+    error_message = "Pre-install script name output should be generated even when script is not created"
+  }
+
+  assert {
+    condition     = output.install_script_name == "test-agent-install_script"
+    error_message = "Install script name output should be correctly formatted"
+  }
+
+  assert {
+    condition     = output.post_install_script_name == "test-agent-post_install_script"
+    error_message = "Post-install script name output should be generated even when script is not created"
+  }
+
+  assert {
+    condition     = output.start_script_name == "test-agent-start_script"
+    error_message = "Start script name output should be correctly formatted"
+  }
+}
+
+# Test with mock data sources
+run "test_with_mock_data" {
+  command = plan
+
+  variables {
+    agent_id        = "mock-agent"
+    agent_name      = "mock-agent"
+    module_dir_name = ".mock-module"
+    install_script  = "echo 'install'"
+    start_script    = "echo 'start'"
+  }
+
+  # Mock the data sources for testing
+  override_data {
+    target = data.coder_workspace.me
+    values = {
+      id            = "test-workspace-id"
+      name          = "test-workspace"
+      owner         = "test-owner"
+      owner_id      = "test-owner-id"
+      template_id   = "test-template-id"
+      template_name = "test-template"
+      access_url    = "https://coder.example.com"
+      start_count   = 1
+      transition    = "start"
+    }
+  }
+
+  override_data {
+    target = data.coder_workspace_owner.me
+    values = {
+      id            = "test-owner-id"
+      email         = "test@example.com"
+      name          = "Test User"
+      session_token = "mock-token"
+    }
+  }
+
+  override_data {
+    target = data.coder_task.me
+    values = {
+      id = "test-task-id"
+    }
+  }
+
+  # Verify scripts are created with mocked data
+  assert {
+    condition     = coder_script.install_script.agent_id == "mock-agent"
+    error_message = "Install script should use the mocked agent ID"
+  }
+
+  assert {
+    condition     = coder_script.start_script.agent_id == "mock-agent"
+    error_message = "Start script should use the mocked agent ID"
+  }
+}
+
+# Test script naming with custom agent_name
+run "test_script_naming" {
+  command = plan
+
+  variables {
+    agent_id        = "test-agent"
+    agent_name      = "custom-name"
+    module_dir_name = ".test-module"
+    install_script  = "echo 'install'"
+    start_script    = "echo 'start'"
+  }
+
+  # Verify script names are constructed correctly
+  # The script should contain references to custom-name-* in the sync commands
+  assert {
+    condition     = can(regex("custom-name-install_script", coder_script.install_script.script))
+    error_message = "Install script should use custom agent_name in sync commands"
+  }
+
+  assert {
+    condition     = can(regex("custom-name-start_script", coder_script.start_script.script))
+    error_message = "Start script should use custom agent_name in sync commands"
+  }
+
+  # Verify outputs use custom agent_name
+  assert {
+    condition     = output.pre_install_script_name == "custom-name-pre_install_script"
+    error_message = "Pre-install script name output should use custom agent_name"
+  }
+
+  assert {
+    condition     = output.install_script_name == "custom-name-install_script"
+    error_message = "Install script name output should use custom agent_name"
+  }
+
+  assert {
+    condition     = output.post_install_script_name == "custom-name-post_install_script"
+    error_message = "Post-install script name output should use custom agent_name"
+  }
+
+  assert {
+    condition     = output.start_script_name == "custom-name-start_script"
+    error_message = "Start script name output should use custom agent_name"
+  }
+}