github.com/ticketmaster/terraform@v0.10.0-beta2.0.20170711045249-a12daf5aba4f/backend/init/init.go (about)

     1  // Package init contains the list of backends that can be initialized and
     2  // basic helper functions for initializing those backends.
     3  package init
     4  
     5  import (
     6  	"sync"
     7  
     8  	"github.com/hashicorp/terraform/backend"
     9  
    10  	backendatlas "github.com/hashicorp/terraform/backend/atlas"
    11  	backendlegacy "github.com/hashicorp/terraform/backend/legacy"
    12  	backendlocal "github.com/hashicorp/terraform/backend/local"
    13  	backendconsul "github.com/hashicorp/terraform/backend/remote-state/consul"
    14  	backendinmem "github.com/hashicorp/terraform/backend/remote-state/inmem"
    15  	backendS3 "github.com/hashicorp/terraform/backend/remote-state/s3"
    16  	backendSwift "github.com/hashicorp/terraform/backend/remote-state/swift"
    17  )
    18  
    19  // backends is the list of available backends. This is a global variable
    20  // because backends are currently hardcoded into Terraform and can't be
    21  // modified without recompilation.
    22  //
    23  // To read an available backend, use the Backend function. This ensures
    24  // safe concurrent read access to the list of built-in backends.
    25  //
    26  // Backends are hardcoded into Terraform because the API for backends uses
    27  // complex structures and supporting that over the plugin system is currently
    28  // prohibitively difficult. For those wanting to implement a custom backend,
    29  // they can do so with recompilation.
    30  var backends map[string]func() backend.Backend
    31  var backendsLock sync.Mutex
    32  
    33  func init() {
    34  	// Our hardcoded backends. We don't need to acquire a lock here
    35  	// since init() code is serial and can't spawn goroutines.
    36  	backends = map[string]func() backend.Backend{
    37  		"atlas":  func() backend.Backend { return &backendatlas.Backend{} },
    38  		"local":  func() backend.Backend { return &backendlocal.Local{} },
    39  		"consul": func() backend.Backend { return backendconsul.New() },
    40  		"inmem":  func() backend.Backend { return backendinmem.New() },
    41  		"swift":  func() backend.Backend { return backendSwift.New() },
    42  		"s3":     func() backend.Backend { return backendS3.New() },
    43  	}
    44  
    45  	// Add the legacy remote backends that haven't yet been convertd to
    46  	// the new backend API.
    47  	backendlegacy.Init(backends)
    48  }
    49  
    50  // Backend returns the initialization factory for the given backend, or
    51  // nil if none exists.
    52  func Backend(name string) func() backend.Backend {
    53  	backendsLock.Lock()
    54  	defer backendsLock.Unlock()
    55  	return backends[name]
    56  }
    57  
    58  // Set sets a new backend in the list of backends. If f is nil then the
    59  // backend will be removed from the map. If this backend already exists
    60  // then it will be overwritten.
    61  //
    62  // This method sets this backend globally and care should be taken to do
    63  // this only before Terraform is executing to prevent odd behavior of backends
    64  // changing mid-execution.
    65  func Set(name string, f func() backend.Backend) {
    66  	backendsLock.Lock()
    67  	defer backendsLock.Unlock()
    68  
    69  	if f == nil {
    70  		delete(backends, name)
    71  		return
    72  	}
    73  
    74  	backends[name] = f
    75  }