terracost

TerraCost

Go library for estimating Terraform costs using ingested cloud vendor prices. It is meant to be imported and used by programs (API's or standalone) with access to a MySQL-compatible database and the Internet.

Installation

go get github.com/cycloidio/terracost

Requirements

• Go 1.15 or newer (older may work but are not supported)
• MySQL database

Provider support

Currently, Terracost supports only a few resources of the AWS provider, however we're actively working on adding more support. See the full list of supported resources on this wiki page.

Usage

Migrating the database

db, err := sql.Open("mysql", "...")

// Can be called on every start of your program, it does nothing if the migrations
// have been executed already.
err := mysql.Migrate(ctx, db, "pricing_migrations")

Ingesting pricing data

db, err := sql.Open("mysql", "...")
backend := mysql.NewBackend(db)

// service can be "AmazonEC2" or "AmazonRDS"
// region is any AWS region, e.g. "us-east-1" or "eu-west-3"
ingester, err := aws.NewIngester(service, region)
err = terracost.IngestPricing(ctx, backend, ingester)

Tracking ingestion progress

We're using the github.com/machinebox/progress library for tracking ingestion progress.

1. Create a channel that will receive progress updates and set up a goroutine (it will print the bytes ingested out of bytes total and remaining time each time progress update is sent on the channel):

progressCh := make(chan progress.Progress, 0)

go func() {
	for p := range progressCh {
		// Check the docs for all available methods: https://pkg.go.dev/github.com/machinebox/progress#Progress
		fmt.Printf("%d / %d (%s remaining)\n", p.N(), p.Size(), p.Remaining().String())
	}
}()

1. Initialize an ingester capable of tracking progress (in this example the channel will receive an update every 5 seconds):

ingester, err := aws.NewIngester(service, region, aws.WithProgress(progressCh, 5*time.Second))

1. Use the ingester as in the previous section.

Estimating a Terraform plan

Plan estimation is possible after all the relevant pricing data have been ingested and stored in the database.

1. Generate a plan using terraform and convert it to JSON:

terraform plan -out update.tfplan
terraform show -json update.tfplan > tfplan.json

1. Read the plan file, estimate it and show the resource differences:

db, err := db.Open("mysql", "...")
backend := mysql.NewBackend(db)

file, err := os.Open("path/to/tfplan.json")
plan, err := terracost.EstimateTerraformPlan(ctx, backend, file)

for _, res := range plan.ResourceDifferences() {
    fmt.Printf("%s: %s -> %s\n", res.Address, res.PriorCost().String(), res.PlannedCost().String())
}

Check the documentation for all available fields.

Contributing

For Contributing Guide, please read CONTIBUTING.md.

License

This project is licensed under the MIT license. Please see LICENSE for more details.