Workspace #

# List all workspaces and the active one (marked with *)
terraform workspace list
# Output:
#   default
# * dev          ← the currently active workspace

# Create a new workspace
terraform workspace new staging
terraform workspace new production

# Switch to another workspace
terraform workspace select production

# Show the active workspace
terraform workspace show
# Output: production

# Delete a workspace (must be empty / no resources)
terraform workspace delete dev

# Using terraform.workspace directly
resource "aws_instance" "web" {
  # Different instance sizes per workspace
  instance_type = terraform.workspace == "production" ? "t3.medium" : "t3.micro"

  tags = {
    Name        = "web-${terraform.workspace}"
    Environment = terraform.workspace
  }
}

# A cleaner pattern: a map lookup based on the workspace
locals {
  # Per-workspace configuration in one place
  workspace_config = {
    dev = {
      instance_type        = "t3.micro"
      instance_count       = 1
      db_instance_class    = "db.t3.micro"
      db_multi_az          = false
      db_backup_retention  = 0
      deletion_protection  = false
    }
    staging = {
      instance_type        = "t3.small"
      instance_count       = 2
      db_instance_class    = "db.t3.small"
      db_multi_az          = false
      db_backup_retention  = 7
      deletion_protection  = false
    }
    production = {
      instance_type        = "t3.medium"
      instance_count       = 3
      db_instance_class    = "db.r5.large"
      db_multi_az          = true
      db_backup_retention  = 30
      deletion_protection  = true
    }
  }

  # Get the configuration for the active workspace
  config = local.workspace_config[terraform.workspace]
}

resource "aws_instance" "web" {
  count         = local.config.instance_count
  instance_type = local.config.instance_type

  tags = {
    Name        = "web-${terraform.workspace}-${count.index + 1}"
    Environment = terraform.workspace
  }
}

resource "aws_db_instance" "main" {
  instance_class    = local.config.db_instance_class
  multi_az          = local.config.db_multi_az
  backup_retention_period = local.config.db_backup_retention
  deletion_protection     = local.config.deletion_protection
}

# GOOD HABIT: Always check the workspace before applying

# Show the active workspace in the shell prompt (add to .bashrc/.zshrc)
# Example for zsh with oh-my-zsh — add the workspace to the prompt
parse_tf_workspace() {
  if [ -d .terraform ]; then
    workspace=$(terraform workspace show 2>/dev/null)
    echo " [tf:$workspace]"
  fi
}
RPROMPT='$(parse_tf_workspace)'

# Or: use aliases that always show the workspace first
alias tfplan='echo "Workspace: $(terraform workspace show)" && terraform plan'
alias tfapply='echo "Workspace: $(terraform workspace show)" && read -p "Continue? [yes/no]: " confirm && [ "$confirm" = "yes" ] && terraform apply'

# Example per-PR environment workflow with workspaces:

# Create a workspace for PR #123
terraform workspace new pr-123
terraform workspace select pr-123

# Deploy the environment for this PR
terraform apply -var="environment=pr-123" -auto-approve

# After the PR is merged, remove the environment
terraform destroy -auto-approve
terraform workspace select default
terraform workspace delete pr-123

SELECTION CRITERIA:

                          Workspace    Directory
Number of environments    < 4          >= 4
Configuration differences Small        Large
Different teams           Same         Different
Different IAM             No           Yes
CI/CD pipelines           Same         Different
Blast radius isolation    Low          High

RECOMMENDATIONS:
- Small projects, 1-2 developers → Workspaces
- Large projects, many teams → Directory-based
- Strict compliance → Directory-based

# Script to manage workspaces
#!/bin/bash
WORKSPACE=$1

# Create the workspace if it doesn't exist
terraform workspace select $WORKSPACE 2>/dev/null ||   terraform workspace new $WORKSPACE

# Apply with workspace-specific variables
terraform apply -var-file="environments/$WORKSPACE.tfvars" -auto-approve

# BEST PRACTICE: Consistent naming conventions

# Format: {project}-{environment}-{component}
terraform workspace new myapp-dev-networking
terraform workspace new myapp-dev-compute
terraform workspace new myapp-staging-networking
terraform workspace new myapp-production-networking

# List all workspaces
terraform workspace list

# Select a workspace
terraform workspace select myapp-production-networking

# Show the current workspace
terraform workspace show

# Delete a workspace (careful!)
terraform workspace delete myapp-old-feature

# Use the workspace name in the configuration
locals {
  # Parse the workspace name
  parts       = split("-", terraform.workspace)
  environment = element(local.parts, 1)  # dev, staging, production
  
  name_prefix = "${local.parts[0]}-${local.environment}"
}

resource "aws_instance" "web" {
  tags = {
    Name        = "${local.name_prefix}-web"
    Environment = local.environment
  }
}

WORKSPACE PROS:
+ Simpler setup
+ Same code, different state
+ Quick switching

WORKSPACE CONS:
- Easy to accidentally apply the wrong env
- Same code = no env-specific customization
- No code review per environment

DIRECTORY PROS:
+ Clear separation
+ Per-environment customization
+ Independent code review
+ Easy to understand

DIRECTORY CONS:
+ More files to maintain
+ Code duplication risk
+ Need shared modules

RECOMMENDATION: Use directory-based
for production, workspaces for dev/testing

# Workspace management commands
terraform workspace list          # List all workspaces
terraform workspace show          # Show the current workspace
terraform workspace select dev    # Switch to the dev workspace
terraform workspace new staging   # Create a new workspace

# Use the workspace in the configuration
resource "aws_instance" "web" {
  instance_type = terraform.workspace == "production" ? "t3.large" : "t3.micro"
  
  tags = {
    Environment = terraform.workspace
  }
}

# Script: switch and apply
#!/bin/bash
ENV=${1:-dev}
terraform workspace select "$ENV"
terraform apply -var-file="environments/$ENV.tfvars"