azure

package
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 Go to latest Published: Apr 24, 2024 License: MIT Imports: 20 Imported by: 2

Documentation

Overview

Package azure Microsoft Azure Blob Storage VFS Implementation

Usage

Rely on github.com/c2fo/vfs/backend 

import(
    "github.com/c2fo/vfs/v6/backend"
    "github.com/c2fo/vfs/v6/backend/azure"
)

func UseFs() error {
    fs := backend.Backend(azure.Scheme)
    ...
}

Or call directly: 

import "github.com/c2fo/vfs/v6/backend/azure"

func DoSomething() {
    fs := azure.NewFilesystem()
    ...
}

azure can be augmented with the following implementation-specific methods. Backend returns vfs.Filesystem interface so it would have to be cast as azure.Filesystem to use the following: 

func DoSomething() {

    ...

    // cast if fs was created using backend.Backend().  Not necessary if created directly from azure.NewFilesystem().
    fs = fs.(azure.Filesystem)

    // to pass in client options
    fs = fs.WithOptions(
        azure.Options{
            AccountName: "...",
            AccountKey: "...
        },
    )

    // to pass specific client, for instance mock client
    client, _ := azure.NewClient(MockAzureClient{...})
    fs = fs.WithClient(client)
}

Authentication

Authentication, by default, occurs automatically when Client() is called. It looks for credentials in the following places, preferring the first location found:

  1. When the ENV vars VFS_AZURE_ENV_NAME, VFS_AZURE_STORAGE_ACCOUNT, VFS_AZURE_TENANT_ID, VFS_AZURE_CLIENT_ID, and VFS_AZURE_CLIENT_SECRET, authentication is performed using an OAuth Token Authenticator. This will allow access to containers from multiple storage accounts.
  2. The ENV vars VFS_AZURE_STORAGE_ACCOUNT and VFS_AZURE_STORAGE_KEY, a shared key authenticator is used. This will allow access to any containers owned by the designated storage account.
  3. If none of the above are present, then an anonymous authenticator is created and only publicly accessible blobs will be available

Index

Constants

View Source 
const Name = "azure"

Name defines the name for the azure implementation

View Source 
const Scheme = "https"

Scheme defines the scheme for the azure implementation

Variables

This section is empty.

Functions

func IsValidURI 

func IsValidURI(u *url.URL) bool

IsValidURI us a utility function used by vfssimple to determine if the given URI is a valid Azure URI

func ParsePath 

func ParsePath(p string) (host, pth string, err error)

ParsePath is a utility function used by vfssimple to separate the host from the path. The first parameter returned is the host and the second parameter is the path.

Types

type BlobProperties 

type BlobProperties struct {
	// Size holds the size of the blob.
	Size uint64

	// LastModified holds the last modified time.Time
	LastModified *time.Time

	// Metadata holds the Azure metadata
	Metadata map[string]string
}

BlobProperties holds a subset of information returned by Blob.GetProperties(..)

func NewBlobProperties 

func NewBlobProperties(azureProps *azblob.BlobGetPropertiesResponse) *BlobProperties

NewBlobProperties creates a new BlobProperties from an azblob.BlobGetPropertiesResponse

type Client 

type Client interface {
	// Properties should return a BlobProperties struct for the blob specified by locationURI, and filePath.  If the
	// blob is not found an error should be returned.
	Properties(locationURI, filePath string) (*BlobProperties, error)

	// SetMetadata should add the metadata specified by the parameter metadata for the blob specified by the parameter
	// file.
	SetMetadata(file vfs.File, metadata map[string]string) error

	// Upload should create or update the blob specified by the file parameter with the contents of the content
	// parameter
	Upload(file vfs.File, content io.ReadSeeker) error

	// Download should return a reader for the blob specified by the file parameter
	Download(file vfs.File) (io.ReadCloser, error)

	// Copy should copy the file specified by srcFile to the file specified by tgtFile
	Copy(srcFile vfs.File, tgtFile vfs.File) error

	// List should return a listing for the specified location. Listings should include the full path for the file.
	List(l vfs.Location) ([]string, error)

	// Delete should delete the file specified by the parameter file.
	Delete(file vfs.File) error

	// DeleteAllVersions should delete all versions of the file specified by the parameter file.
	DeleteAllVersions(file vfs.File) error
}

The Client interface contains methods that perform specific operations to Azure Blob Storage. This interface is here so we can write mocks over the actual functionality.

type DefaultClient 

type DefaultClient struct {
	// contains filtered or unexported fields
}

DefaultClient is the main implementation that actually makes the calls to Azure Blob Storage

func NewClient 

func NewClient(options *Options) (*DefaultClient, error)

NewClient initializes a new DefaultClient

func (*DefaultClient) Copy 

func (a *DefaultClient) Copy(srcFile, tgtFile vfs.File) error

Copy copies srcFile to the destination tgtFile within Azure Blob Storage. Note that in the case where we get encoded spaces in the file name (i.e. %20) the '%' must be encoded or the copy command will return a not found error.

func (*DefaultClient) Delete 

func (a *DefaultClient) Delete(file vfs.File) error

Delete deletes the given file from Azure Blob Storage.

func (*DefaultClient) DeleteAllVersions added in v6.5.0 

func (a *DefaultClient) DeleteAllVersions(file vfs.File) error

DeleteAllVersions deletes all the versions of the given file from Azure Blob Storage. First the file blob is deleted, then each version of the blob is deleted. If soft deletion is enabled for blobs in the storage account, each version will be marked for deletion and will be permanently deleted by Azure as per the soft deletion policy.

func (*DefaultClient) Download 

func (a *DefaultClient) Download(file vfs.File) (io.ReadCloser, error)

Download returns an io.ReadCloser for the given vfs.File

func (*DefaultClient) List 

func (a *DefaultClient) List(l vfs.Location) ([]string, error)

List will return a listing of the contents of the given location. Each item in the list will contain the full key as specified by the azure blob (incliding the virtual 'path').

func (*DefaultClient) Properties 

func (a *DefaultClient) Properties(containerURI, filePath string) (*BlobProperties, error)

Properties fetches the properties for the blob specified by the parameters containerURI and filePath

func (*DefaultClient) SetMetadata 

func (a *DefaultClient) SetMetadata(file vfs.File, metadata map[string]string) error

SetMetadata sets the given metadata for the blob

func (*DefaultClient) Upload 

func (a *DefaultClient) Upload(file vfs.File, content io.ReadSeeker) error

Upload uploads a new file to Azure Blob Storage

type DefaultTokenCredentialFactory 

type DefaultTokenCredentialFactory struct{}

DefaultTokenCredentialFactory knows how to make azblob.TokenCredential structs for OAuth authentication

func (*DefaultTokenCredentialFactory) New 

func (f *DefaultTokenCredentialFactory) New(tenantID, clientID, clientSecret, azureEnvName string) (azblob.TokenCredential, error)

New creates a new azblob.TokenCredntial struct

type File 

type File struct {
	// contains filtered or unexported fields
}

File implements the vfs.File interface for Azure Blob Storage

func (*File) Close 

func (f *File) Close() error

Close cleans up all of the backing data structures used for reading/writing files. This includes, closing the temp file, uploading the contents of the temp file to Azure Blob Storage (if necessary), and calling Seek(0, 0).

func (*File) CopyToFile 

func (f *File) CopyToFile(file vfs.File) (err error)

CopyToFile puts the contents of the receiver (f *File) into the passed vfs.File parameter.

func (*File) CopyToLocation 

func (f *File) CopyToLocation(location vfs.Location) (vfs.File, error)

CopyToLocation creates a copy of *File, using the file's current name as the new file's name at the given location. If the given location is also azure, the azure API for copying files will be utilized, otherwise, standard io.Copy will be done to the new file.

func (*File) Delete 

func (f *File) Delete(opts ...options.DeleteOption) error

Delete deletes the file. If DeleteAllVersions option is provided, each version of the file is deleted. NOTE: if soft deletion is enabled, it will mark all versions as soft deleted, and they will be removed by Azure as per soft deletion policy. Returns any error returned by the API.

func (*File) Exists 

func (f *File) Exists() (bool, error)

Exists returns true/false if the file exists/does not exist on Azure

func (*File) LastModified 

func (f *File) LastModified() (*time.Time, error)

LastModified returns the last modified time as a time.Time

func (*File) Location 

func (f *File) Location() vfs.Location

Location returns a Location instance for the files current location

func (*File) MoveToFile 

func (f *File) MoveToFile(file vfs.File) error

MoveToFile copies the receiver to the specified file and deletes the original file.

func (*File) MoveToLocation 

func (f *File) MoveToLocation(location vfs.Location) (vfs.File, error)

MoveToLocation copies the receiver to the passed location. After the copy succeeds, the original is deleted.

func (*File) Name 

func (f *File) Name() string

Name returns the name of the file

func (*File) Path 

func (f *File) Path() string

Path returns full path with leading slash.

func (*File) Read 

func (f *File) Read(p []byte) (n int, err error)

Read implements the io.Reader interface. For this to work with Azure Blob Storage, a temporary local copy of the file is created and read operations are performed against that. The temp file is closed and flushed to Azure when f.Close() is called.

func (*File) Seek 

func (f *File) Seek(offset int64, whence int) (int64, error)

Seek implements the io.Seeker interface. For this to work with Azure Blob Storage, a temporary local copy of the file is created and operations are performed against that. The temp file is closed and flushed to Azure when f.Close() is called.

func (*File) Size 

func (f *File) Size() (uint64, error)

Size returns the size of the blob

func (*File) String 

func (f *File) String() string

String returns the file URI

func (*File) Touch 

func (f *File) Touch() error

Touch creates a zero-length file on the vfs.File if no File exists. If the file exists, Touch updates the file's last modified parameter.

func (*File) URI 

func (f *File) URI() string

URI returns a full Azure URI for the file

func (*File) Write 

func (f *File) Write(p []byte) (int, error)

Write implements the io.Writer interface. Writes are performed against a temporary local file. The temp file is closed and flushed to Azure with f.Close() is called.

type FileSystem 

type FileSystem struct {
	// contains filtered or unexported fields
}

FileSystem implements the vfs.FileSystem interface for Azure Blob Storage

func NewFileSystem 

func NewFileSystem() *FileSystem

NewFileSystem creates a new default FileSystem. This will set the options options.AccountName and options.AccountKey with the env variables AZURE_STORAGE_ACCOUNT and AZURE_STORAGE_ACCESS_KEY respectively.

func (*FileSystem) Client 

func (fs *FileSystem) Client() (Client, error)

Client returns a Client to perform operations against Azure Blob Storage

func (*FileSystem) Host 

func (fs *FileSystem) Host() string

Host returns the host portion of the URI. For azure this consists of <account_name>.blob.core.windows.net.

func (*FileSystem) Name 

func (fs *FileSystem) Name() string

Name returns "azure"

func (*FileSystem) NewFile 

func (fs *FileSystem) NewFile(volume, absFilePath string) (vfs.File, error)

NewFile returns the azure implementation of vfs.File

func (*FileSystem) NewLocation 

func (fs *FileSystem) NewLocation(volume, absLocPath string) (vfs.Location, error)

NewLocation returns the azure implementation of vfs.Location

func (*FileSystem) Retry 

func (fs *FileSystem) Retry() vfs.Retry

Retry returns the default retry function. This is overridable via the WithOptions function.

func (*FileSystem) Scheme 

func (fs *FileSystem) Scheme() string

Scheme returns "https" as the initial part of the URI i.e. https://..

func (*FileSystem) WithClient 

func (fs *FileSystem) WithClient(client Client) *FileSystem

WithClient allows the caller to specify a specific client to be used

func (*FileSystem) WithOptions 

func (fs *FileSystem) WithOptions(opts vfs.Options) *FileSystem

WithOptions allows the caller to override the default options

type Location 

type Location struct {
	// contains filtered or unexported fields
}

Location is the azure implementation of vfs.Location

func (*Location) ChangeDir 

func (l *Location) ChangeDir(relLocPath string) error

ChangeDir changes the current location's path to the new, relative path.

func (*Location) ContainerURL 

func (l *Location) ContainerURL() string

ContainerURL returns the URL for the Azure Blob Storage container.

func (*Location) DeleteFile 

func (l *Location) DeleteFile(relFilePath string, opts ...options.DeleteOption) error

DeleteFile deletes the file at the given path, relative to the current location.

func (*Location) Exists 

func (l *Location) Exists() (bool, error)

Exists returns true if the file exists and false. In the case of errors false is always returned along with the error

func (*Location) FileSystem 

func (l *Location) FileSystem() vfs.FileSystem

FileSystem returns the azure FileSystem instance

func (*Location) List 

func (l *Location) List() ([]string, error)

List returns a list of base names for the given location.

func (*Location) ListByPrefix 

func (l *Location) ListByPrefix(prefix string) ([]string, error)

ListByPrefix returns a list of base names that contain the given prefix

func (*Location) ListByRegex 

func (l *Location) ListByRegex(regex *regexp.Regexp) ([]string, error)

ListByRegex returns a list of base names that match the given regular expression

func (*Location) NewFile 

func (l *Location) NewFile(relFilePath string) (vfs.File, error)

NewFile returns a new file instance at the given path, relative to the current location.

func (*Location) NewLocation 

func (l *Location) NewLocation(relLocPath string) (vfs.Location, error)

NewLocation creates a new location instance relative to the current location's path.

func (*Location) Path 

func (l *Location) Path() string

Path returns the absolute path for the Location

func (*Location) String 

func (l *Location) String() string

String returns the URI

func (*Location) URI 

func (l *Location) URI() string

URI returns a URI string for the azure location.

func (*Location) Volume 

func (l *Location) Volume() string

Volume returns the azure container. Azure containers are equivalent to AWS Buckets

type MockAzureClient 

type MockAzureClient struct {
	PropertiesError  error
	PropertiesResult *BlobProperties
	ExpectedError    error
	ExpectedResult   interface{}
}

MockAzureClient is a mock implementation of azure.Client.

func (*MockAzureClient) Copy 

func (a *MockAzureClient) Copy(srcFile, tgtFile vfs.File) error

Copy returns the value of ExpectedError

func (*MockAzureClient) Delete 

func (a *MockAzureClient) Delete(file vfs.File) error

Delete returns the value of ExpectedError

func (*MockAzureClient) DeleteAllVersions added in v6.5.0 

func (a *MockAzureClient) DeleteAllVersions(file vfs.File) error

DeleteAllVersions returns the value of ExpectedError

func (*MockAzureClient) Download 

func (a *MockAzureClient) Download(file vfs.File) (io.ReadCloser, error)

Download returns ExpectedResult if it exists, otherwise it returns ExpectedError

func (*MockAzureClient) List 

func (a *MockAzureClient) List(l vfs.Location) ([]string, error)

List returns the value of ExpectedResult if it exists, otherwise it returns ExpectedError.

func (*MockAzureClient) Properties 

func (a *MockAzureClient) Properties(locationURI, filePath string) (*BlobProperties, error)

Properties returns a PropertiesResult if it exists, otherwise it will return the value of PropertiesError

func (*MockAzureClient) SetMetadata 

func (a *MockAzureClient) SetMetadata(file vfs.File, metadata map[string]string) error

SetMetadata returns the value of ExpectedError

func (*MockAzureClient) Upload 

func (a *MockAzureClient) Upload(file vfs.File, content io.ReadSeeker) error

Upload returns the value of ExpectedError

type MockStorageError 

type MockStorageError struct {
	azblob.ResponseError
}

MockStorageError is a mock for the azblob.StorageError interface

func (MockStorageError) Error 

func (mse MockStorageError) Error() string

Error returns empty string

func (MockStorageError) Response 

func (mse MockStorageError) Response() *http.Response

Response returns nil

func (MockStorageError) ServiceCode 

func (mse MockStorageError) ServiceCode() azblob.ServiceCodeType

ServiceCode always returns "BlobNotFound" to simulate the not found condition

func (MockStorageError) Temporary 

func (mse MockStorageError) Temporary() bool

Temporary returns nil

func (MockStorageError) Timeout 

func (mse MockStorageError) Timeout() bool

Timeout returns nil

type MockTokenCredentialFactory 

type MockTokenCredentialFactory struct{}

MockTokenCredentialFactory knows how to create a "do-nothing" credential used for unit testing

func (*MockTokenCredentialFactory) New 

func (f *MockTokenCredentialFactory) New(tenantID, clientID, clientSecret, azureEnvName string) (azblob.TokenCredential, error)

New creates a new azblob.TokenCredntial struct

type Options 

type Options struct {
	// AccountName holds the Azure Blob Storage account name for authentication.  This field is required for all
	// authentication types.
	AccountName string

	// AccountKey holds the Azure Blob Storage account key for authentication.  This field is used for shared key
	// authentication.
	AccountKey string

	// TenantID holds the Azure Service Account tenant id for authentication.  This field is used for OAuth token
	// based authentication.
	TenantID string

	// ClientID holds the Azure Service Account client id for authentication.  This field is used for OAuth token
	// based authentication.
	ClientID string

	// ClientSecret holds the Azure Service Account client secret for authentication.  This field is used for OAuth token
	// based authentication.
	ClientSecret string

	// AzureEnvName holds the name for the Azure environment.  This field is used for OAuth token
	// based authentication.
	AzureEnvName string

	// RetryFunc holds the retry function
	RetryFunc vfs.Retry

	// Buffer Size In Bytes Used with utils.TouchCopyBuffered
	FileBufferSize int
	// contains filtered or unexported fields
}

Options contains options necessary for the azure vfs implementation

func NewOptions 

func NewOptions() *Options

NewOptions creates a new Options struct by populating values from environment variables. 

Env Vars:
  *VFS_AZURE_STORAGE_ACCOUNT
  *VFS_AZURE_STORAGE_ACCESS_KEY
  *VFS_AZURE_TENANT_ID
  *VFS_AZURE_CLIENT_ID
  *VFS_AZURE_CLIENT_SECRET
  *VFS_AZURE_ENV_NAME

func (*Options) Credential 

func (o *Options) Credential() (azblob.Credential, error)

Credential returns an azblob.Credential struct based on how options are configured. Options are checked and evaluated in the following order:

  1. If TenantID, ClientID, and ClientSecret are non-empty, return azblob.TokenCredential. This form of authentication is used with service accounts and can be used to access containers across multiple storage accounts.
  2. If AccountName, and AccountKey are non-empty, return azblob.SharedKeyCredential. This form or authentication is used with storage accounts and only provides access to a single storage account.
  3. Returns an anonymous credential. This allows access only to public blobs.

type TokenCredentialFactory 

type TokenCredentialFactory interface {
	// New creates a new azblob.TokenCredntial struct
	New(tenantID, clientID, clientSecret, azureEnvName string) (azblob.TokenCredential, error)
}

TokenCredentialFactory is an interface that provides a single factory method to create azure.TokenCredentials. This interface is provided to allow for mocking in unit tests.

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