github.com/vtorhonen/terraform@v0.9.0-beta2.0.20170307220345-5d894e4ffda7/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  )
    16  
    17  // backends is the list of available backends. This is a global variable
    18  // because backends are currently hardcoded into Terraform and can't be
    19  // modified without recompilation.
    20  //
    21  // To read an available backend, use the Backend function. This ensures
    22  // safe concurrent read access to the list of built-in backends.
    23  //
    24  // Backends are hardcoded into Terraform because the API for backends uses
    25  // complex structures and supporting that over the plugin system is currently
    26  // prohibitively difficult. For those wanting to implement a custom backend,
    27  // they can do so with recompilation.
    28  var backends map[string]func() backend.Backend
    29  var backendsLock sync.Mutex
    30  
    31  func init() {
    32  	// Our hardcoded backends. We don't need to acquire a lock here
    33  	// since init() code is serial and can't spawn goroutines.
    34  	backends = map[string]func() backend.Backend{
    35  		"atlas":  func() backend.Backend { return &backendatlas.Backend{} },
    36  		"local":  func() backend.Backend { return &backendlocal.Local{} },
    37  		"consul": func() backend.Backend { return backendconsul.New() },
    38  		"inmem":  func() backend.Backend { return backendinmem.New() },
    39  	}
    40  
    41  	// Add the legacy remote backends that haven't yet been convertd to
    42  	// the new backend API.
    43  	backendlegacy.Init(backends)
    44  }
    45  
    46  // Backend returns the initialization factory for the given backend, or
    47  // nil if none exists.
    48  func Backend(name string) func() backend.Backend {
    49  	backendsLock.Lock()
    50  	defer backendsLock.Unlock()
    51  	return backends[name]
    52  }
    53  
    54  // Set sets a new backend in the list of backends. If f is nil then the
    55  // backend will be removed from the map. If this backend already exists
    56  // then it will be overwritten.
    57  //
    58  // This method sets this backend globally and care should be taken to do
    59  // this only before Terraform is executing to prevent odd behavior of backends
    60  // changing mid-execution.
    61  func Set(name string, f func() backend.Backend) {
    62  	backendsLock.Lock()
    63  	defer backendsLock.Unlock()
    64  
    65  	if f == nil {
    66  		delete(backends, name)
    67  		return
    68  	}
    69  
    70  	backends[name] = f
    71  }