pulumi-troubleshooting

Pulumi Infrastructure Troubleshooting Skill

Common Pulumi TypeScript Errors and Solutions

1. "This expression is not callable. Type 'never' has no call signatures"

Cause: TypeScript infers a type as never when working with Pulumi Outputs, especially with arrays.

Solution: Wrap the value in pulumi.output() and properly type the callback:

// ❌ Bad - TypeScript can't infer the type
value: pulumi.all(config.vpc.publicSubnets.map((s: any) => s.id))

// ✅ Good - Explicitly wrap and type
value: pulumi.output(config.vpc.publicSubnets).apply((subnets: any[]) =>
  pulumi.all(subnets.map((s: any) => s.id)).apply(ids => ids.join(","))
)

2. "Modifiers cannot appear here" (export in conditional blocks)

Cause: TypeScript doesn't allow export statements inside if blocks.

Solution: Use optional chaining for conditional exports:

// ❌ Bad
if (opensearch) {
  export const opensearchEndpoint = opensearch.endpoint;
}

// ✅ Good
export const opensearchEndpoint = opensearch?.endpoint;

3. "Configuration key 'aws:region' is not namespaced by the project"

Cause: Pulumi.yaml config with namespaced keys (e.g., aws:region) cannot use default attribute.

Solution: Remove the config section or don't set defaults for provider configs:

# ❌ Bad
config:
  aws:region:
    description: AWS region
    default: us-east-1

# ✅ Good - set via workflow/CLI instead
config:
  app:domainName:
    description: Domain name

4. Stack Not Found Errors

Cause: Pulumi stack doesn't exist yet in new environments.

Solution: Use || operator to create if not exists:

pulumi stack select $STACK || pulumi stack init $STACK

5. Working with Pulumi Outputs

Key Concepts:

• pulumi.Output<T> is a promise-like wrapper for async values
• Use .apply() to transform Output values
• Use pulumi.all([...]) to combine multiple Outputs
• Use pulumi.output(value) to wrap plain values as Outputs