How to fix Error: Invalid value for input variable - value is not compatible with the variable's type constraint in Terraform

variable "environment" {
  type = string  # String type expected
}

variable "instance_count" {
  type = number  # Number type expected
}

variable "tags" {
  type = map(string)  # Map with string values
}

# WRONG - providing a number when string is expected
variable "environment" {
  type = string
}
environment = 123  # Error! Should be a string

# CORRECT - provide a string
environment = "production"

# WRONG - mixing types in a list
variable "allowed_ports" {
  type = list(number)
}
allowed_ports = [80, "443", 8080]  # Error! "443" is a string

# CORRECT - all numbers
allowed_ports = [80, 443, 8080]

# WRONG - mixing types in a map
variable "settings" {
  type = map(string)
}
settings = {
  name = "MyApp"
  count = 5  # Error! 5 is a number, not a string
}

# CORRECT - all values are strings
settings = {
  name = "MyApp"
  count = "5"
}

# Strings must be quoted
environment = "dev"
region = "us-east-1"

# Numbers are unquoted
replicas = 3
port = 8080

# Lists use square brackets with commas
availability_zones = ["us-east-1a", "us-east-1b", "us-east-1c"]

# Maps use curly braces with key = value pairs
labels = {
  team = "platform"
  env = "staging"
}

# Boolean values are lowercase
enable_monitoring = true

variable "environment" {
  type = string
  validation {
    condition     = contains(["dev", "staging", "prod"], var.environment)
    error_message = "Environment must be dev, staging, or prod."
  }
}

# Valid values: "dev", "staging", "prod"
# Invalid: "production", "test", "development"
environment = "prod"  # OK
environment = "development"  # ERROR - not in allowed list

# String
terraform apply -var="name=MyApp"

# Number
terraform apply -var="count=5"

# Boolean
terraform apply -var="enabled=true"

# List (use JSON syntax)
terraform apply -var='ports=[80,443,8080]'

# Map (use JSON syntax)
terraform apply -var='labels={"team":"platform","env":"prod"}'

# Object (use JSON syntax)
terraform apply -var='config={"name":"app","replicas":3}'

terraform validate

# Create a test file
cat > test.tfvars <<EOF
environment = "dev"
instance_count = 3
enabled = true
tags = {
  team = "platform"
  managed = "true"
}
EOF

# Test with terraform plan
terraform plan -var-file="test.tfvars"