github.com/profects/terraform@v0.9.0-beta1.0.20170227135739-92d4809db30d/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  	backendlegacy "github.com/hashicorp/terraform/backend/legacy"
    11  	backendlocal "github.com/hashicorp/terraform/backend/local"
    12  	backendconsul "github.com/hashicorp/terraform/backend/remote-state/consul"
    13  	backendinmem "github.com/hashicorp/terraform/backend/remote-state/inmem"
    14  )
    15  
    16  // backends is the list of available backends. This is a global variable
    17  // because backends are currently hardcoded into Terraform and can't be
    18  // modified without recompilation.
    19  //
    20  // To read an available backend, use the Backend function. This ensures
    21  // safe concurrent read access to the list of built-in backends.
    22  //
    23  // Backends are hardcoded into Terraform because the API for backends uses
    24  // complex structures and supporting that over the plugin system is currently
    25  // prohibitively difficult. For those wanting to implement a custom backend,
    26  // they can do so with recompilation.
    27  var backends map[string]func() backend.Backend
    28  var backendsLock sync.Mutex
    29  
    30  func init() {
    31  	// Our hardcoded backends. We don't need to acquire a lock here
    32  	// since init() code is serial and can't spawn goroutines.
    33  	backends = map[string]func() backend.Backend{
    34  		"local":  func() backend.Backend { return &backendlocal.Local{} },
    35  		"consul": func() backend.Backend { return backendconsul.New() },
    36  		"inmem":  func() backend.Backend { return backendinmem.New() },
    37  	}
    38  
    39  	// Add the legacy remote backends that haven't yet been convertd to
    40  	// the new backend API.
    41  	backendlegacy.Init(backends)
    42  }
    43  
    44  // Backend returns the initialization factory for the given backend, or
    45  // nil if none exists.
    46  func Backend(name string) func() backend.Backend {
    47  	backendsLock.Lock()
    48  	defer backendsLock.Unlock()
    49  	return backends[name]
    50  }
    51  
    52  // Set sets a new backend in the list of backends. If f is nil then the
    53  // backend will be removed from the map. If this backend already exists
    54  // then it will be overwritten.
    55  //
    56  // This method sets this backend globally and care should be taken to do
    57  // this only before Terraform is executing to prevent odd behavior of backends
    58  // changing mid-execution.
    59  func Set(name string, f func() backend.Backend) {
    60  	backendsLock.Lock()
    61  	defer backendsLock.Unlock()
    62  
    63  	if f == nil {
    64  		delete(backends, name)
    65  		return
    66  	}
    67  
    68  	backends[name] = f
    69  }