tfsource

Documentation

Index

• func IsLocalSource(sourceUrl *url.URL) bool
• type TerraformSource
  • func NewTerraformSource(source string, downloadDir string, workingDir string, logger *logrus.Entry) (*TerraformSource, error)
  • func (terraformSource TerraformSource) EncodeSourceVersion() (string, error)
  • func (src *TerraformSource) String() string
  • func (terraformSource TerraformSource) WriteVersionFile() error

Functions

func IsLocalSource

func IsLocalSource(sourceUrl *url.URL) bool

Returns true if the given URL refers to a path on the local file system

Types

type TerraformSource

type TerraformSource struct {
	// A canonical version of RawSource, in URL format
	CanonicalSourceURL *url.URL

	// The folder where we should download the source to
	DownloadDir string

	// The folder in DownloadDir that should be used as the working directory for Terraform
	WorkingDir string

	// The path to a file in DownloadDir that stores the version number of the code
	VersionFile string

	Logger logrus.FieldLogger
}

This struct represents information about Terraform source code that needs to be downloaded

func NewTerraformSource

func NewTerraformSource(source string, downloadDir string, workingDir string, logger *logrus.Entry) (*TerraformSource, error)

Take the given source path and create a TerraformSource struct from it, including the folder where the source should be downloaded to. Our goal is to reuse the download folder for the same source URL between Terragrunt runs. Otherwise, for every Terragrunt command, you'd have to wait for Terragrunt to download your Terraform code, download that code's dependencies (terraform get), and configure remote state (terraform remote config), which is very slow.

To maximize reuse, given a working directory w and a source URL s, we download code from S into the folder /T/W/H where:

1. S is the part of s before the double-slash (//). This typically represents the root of the repo (e.g. github.com/foo/infrastructure-modules). We download the entire repo so that relative paths to other files in that repo resolve correctly. If no double-slash is specified, all of s is used.
1. T is the OS temp dir (e.g. /tmp).
2. W is the base 64 encoded sha1 hash of w. This ensures that if you are running Terragrunt concurrently in multiple folders (e.g. during automated tests), then even if those folders are using the same source URL s, they do not overwrite each other.
3. H is the base 64 encoded sha1 of S without its query string. For remote source URLs (e.g. Git URLs), this is based on the assumption that the scheme/host/path of the URL (e.g. git::github.com/foo/bar) identifies the repo, and we always want to download the same repo into the same folder (see the encodeSourceName method). We also assume the version of the module is stored in the query string (e.g. ref=v0.0.3), so we store the base 64 encoded sha1 of the query string in a file called .terragrunt-source-version within /T/W/H.

The downloadTerraformSourceIfNecessary decides when we should download the Terraform code and when not to. It uses the following rules:

1. Always download source URLs pointing to local file paths.
2. Only download source URLs pointing to remote paths if /T/W/H doesn't already exist or, if it does exist, if the version number in /T/W/H/.terragrunt-source-version doesn't match the current version.

func (TerraformSource) EncodeSourceVersion

func (terraformSource TerraformSource) EncodeSourceVersion() (string, error)

Encode a version number for the given source. When calculating a version number, we take the query string of the source URL, calculate its sha1, and base 64 encode it. For remote URLs (e.g. Git URLs), this is based on the assumption that the scheme/host/path of the URL (e.g. git::github.com/foo/bar) identifies the module name and the query string (e.g. ?ref=v0.0.3) identifies the version. For local file paths, there is no query string, so the same file path (/foo/bar) is always considered the same version. To detect changes the file path will be hashed and returned as version. In case of hash error the default encoded source version will be returned. See also the encodeSourceName and ProcessTerraformSource methods.

func (*TerraformSource) String

func (src *TerraformSource) String() string

func (TerraformSource) WriteVersionFile

func (terraformSource TerraformSource) WriteVersionFile() error

Write a file into the DownloadDir that contains the version number of this source code. The version number is calculated using the EncodeSourceVersion method.