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remote_file Resource

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To suggest a change, edit the remote_file.rb file and submit a pull request to the Chef Infra Client repository.

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Use the remote_file resource to transfer a file from a remote location using file specificity. This resource is similar to the file resource.

Note

Fetching files from the files/ directory in a cookbook should be done with the cookbook_file resource.

Syntax

A remote_file resource block manages files by using files that exist remotely. For example, to write the home page for an Apache website:

remote_file '/var/www/customers/public_html/index.html' do
  source 'http://somesite.com/index.html'
  owner 'web_admin'
  group 'web_admin'
  mode '0755'
  action :create
end

where:

  • '/var/www/customers/public_html/index.html' is path to the file to be created
  • 'http://somesite.com/index.html' specifies the location of the remote file, the file is downloaded from there
  • owner, group, and mode define the permissions

The full syntax for all of the properties that are available to the remote_file resource is:

remote_file 'name' do
  atomic_update              true, false
  authentication             Symbol # default value: :remote
  backup                     Integer, false # default value: 5
  checksum                   String
  content                    String
  deny_rights
  force_unlink               true, false # default value: false
  ftp_active_mode            true, false # default value: false
  headers                    Hash # default value: {}
  http_options               Hash # default value: {}
  manage_symlink_source      true, false
  path                       String # default value: 'name' unless specified
  remote_domain              String
  remote_password            String
  remote_user                String
  rights
  show_progress              true, false # default value: false
  ssl_verify_mode            Symbol
  use_conditional_get        true, false # default value: true
  use_etag                   true, false # default value: true
  use_last_modified          true, false # default value: true
  action                     Symbol # defaults to :create if not specified
end

where:

  • remote_file is the resource.
  • name is the name given to the resource block.
  • action identifies which steps Chef Infra Client will take to bring the node into the desired state.
  • atomic_update, authentication, backup, checksum, content, deny_rights, force_unlink, ftp_active_mode, headers, http_options, manage_symlink_source, path, remote_domain, remote_password, remote_user, rights, show_progress, ssl_verify_mode, use_conditional_get, use_etag, and use_last_modified are the properties available to this resource.

Actions

The remote_file resource has the following actions:

:create
(default) Create a file. If a file already exists (but does not match), update that file to match.
:create_if_missing
Create a file only if the file does not exist. When the file exists, nothing happens.
:delete
Delete a file.
:nothing
This resource block does not act unless notified by another resource to take action. Once notified, this resource block either runs immediately or is queued up to run at the end of a Chef Infra Client run.
:touch
Touch a file. This updates the access (atime) and file modification (mtime) times for a file. (This action may be used with this resource, but is typically only used with the file resource.)

Properties

The remote_file resource has the following properties:

atomic_update
Ruby Type: true, false | Default Value: False if modifying /etc/hosts, /etc/hostname, or /etc/resolv.conf within Docker containers. Otherwise default to the client.rb 'file_atomic_update' config value.

Perform atomic file updates on a per-resource basis. Set to true for atomic file updates. Set to false for non-atomic file updates. This setting overrides file_atomic_update, which is a global setting found in the client.rb file.

authentication
Ruby Type: Symbol | Default Value: :remote
Allowed Values: :local, :remote

backup
Ruby Type: Integer, false | Default Value: 5

The number of backups to be kept in /var/chef/backup (for UNIX- and Linux-based platforms) or C:/chef/backup (for the Microsoft Windows platform). Set to false to prevent backups from being kept.

checksum
Ruby Type: String

Optional, see use_conditional_get. The SHA-256 checksum of the file. Use to prevent a file from being re-downloaded. When the local file matches the checksum, Chef Infra Client does not download it.

content
Ruby Type: String

A string that is written to the file. The contents of this property replace any previous content when this property has something other than the default value. The default behavior will not modify content.

force_unlink
Ruby Type: true, false | Default Value: false

How Chef Infra Client handles certain situations when the target file turns out not to be a file. For example, when a target file is actually a symlink. Set to true for Chef Infra Client to delete the non-file target and replace it with the specified file. Set to false for Chef Infra Client to raise an error.

ftp_active_mode
Ruby Type: true, false | Default Value: false

Whether Chef Infra Client uses active or passive FTP. Set to true to use active FTP.

group
Ruby Type: Integer, String

A string or ID that identifies the group owner by group name or SID, including fully qualified group names such as domain\group or group@domain. If this value is not specified, existing groups remain unchanged and new group assignments use the default POSIX group (if available).

headers
Ruby Type: Hash | Default Value: {}

A Hash of custom headers. For example:

headers({ "Cookie" => "user=some_user; pass=p@ssw0rd!" })

or:

headers({ "Referer" => "#{header}" })

or:

headers( "Authorization"=>"Basic #{ Base64.encode64("#{username}:#{password}").gsub("\n", "") }" )

http_options
Ruby Type: Hash | Default Value: {}

A Hash of custom HTTP options. For example: http_options({ http_retry_count: 0, http_retry_delay: 2 })

New in Chef Infra Client 17.5

manage_symlink_source
Ruby Type: true, false | Default Value: true

Change the behavior of the file resource if it is pointed at a symlink. When this value is set to true, Chef Infra Client will manage the symlink’s permissions or will replace the symlink with a normal file if the resource has content. When this value is set to false, Chef Infra Client will follow the symlink and will manage the permissions and content of symlink’s target file. The default behavior is true but emits a warning that the default value will be changed to false in a future version; setting this explicitly to true or false suppresses this warning.

mode
Ruby Type: Integer, String

A quoted 3-5 character string that defines the octal mode. For example: '755', '0755', or 00755. If mode is not specified and if the file already exists, the existing mode on the file is used. If mode is not specified, the file does not exist, and the :create action is specified, Chef Infra Client assumes a mask value of '0777' and then applies the umask for the system on which the file is to be created to the mask value. For example, if the umask on a system is '022', Chef Infra Client uses the default value of '0755'. The behavior is different depending on the platform. UNIX- and Linux-based systems: A quoted 3-5 character string that defines the octal mode that is passed to chmod. For example: '755', '0755', or 00755. If the value is specified as a quoted string, it works exactly as if the chmod command was passed. If the value is specified as an integer, prepend a zero (0) to the value to ensure that it is interpreted as an octal number. For example, to assign read, write, and execute rights for all users, use '0777' or '777'; for the same rights, plus the sticky bit, use 01777 or '1777'. Microsoft Windows: A quoted 3-5 character string that defines the octal mode that is translated into rights for Microsoft Windows security. For example: '755', '0755', or 00755. Values up to '0777' are allowed (no sticky bits) and mean the same in Microsoft Windows as they do in UNIX, where 4 equals GENERIC_READ, 2 equals GENERIC_WRITE, and 1 equals GENERIC_EXECUTE. This property cannot be used to set :full_control. This property has no effect if not specified, but when it and rights are both specified, the effects are cumulative.

owner
Ruby Type: Integer, String

A string or ID that identifies the group owner by user name or SID, including fully qualified user names such as domain\user or user@domain. If this value is not specified, existing owners remain unchanged and new owner assignments use the current user (when necessary).

path
Ruby Type: String | Default Value: The resource block's name

The full path to the file, including the file name and its extension. Default value: the name of the resource block. See “Syntax” section above for more information.

remote_domain
Ruby Type: String

Windows only The domain of the user specified by the remote_user property. By default the resource will authenticate against the domain of the remote system, or as a local account if the remote system is not joined to a domain. If the remote system is not part of a domain, it is necessary to authenticate as a local user on the remote system by setting the domain to ., for example: remote_domain ‘.’. The domain may also be specified as part of the remote_user property.

New in Chef Client 13.4

remote_password
Ruby Type: String

Windows only The password of the user specified by the remote_user property. This property is required if remote_user is specified and may only be specified if remote_user is specified. The sensitive property for this resource will automatically be set to true if remote_password is specified.

New in Chef Client 13.4

remote_user
Ruby Type: String

Windows only The name of a user with access to the remote file specified by the source property. The user name may optionally be specified with a domain, such as: domain\user or user@my.dns.domain.com via Universal Principal Name (UPN) format. The domain may also be set using the remote_domain property. Note that this property is ignored if source is not a UNC path. If this property is specified, the remote_password property is required.

New in Chef Client 13.4

rights
Ruby Type: Integer, String

Microsoft Windows only. The permissions for users and groups in a Microsoft Windows environment. For example: rights <permissions>, <principal>, <options> where <permissions> specifies the rights granted to the principal, <principal> is the group or user name, and <options> is a Hash with one (or more) advanced rights options.

source
Ruby Type: String, Array

Required. The location of the source file. The location of the source file may be HTTP (http://), FTP (ftp://), SFTP (sftp://), local (file:///), or UNC (\\host\share\file.tar.gz). There are many ways to define the location of a source file. By using a path: ruby source 'http://couchdb.apache.org/img/sketch.png' By using FTP: ruby source 'ftp://remote_host/path/to/img/sketch.png' By using SFTP: ruby source 'sftp://username:password@remote_host:22/path/to/img/sketch.png' By using a local path: ruby source 'file:///path/to/img/sketch.png' By using a Microsoft Windows UNC: ruby source '\\\\path\\to\\img\\sketch.png' By using a node attribute: ruby source node['nginx']['foo123']['url'] By using attributes to define paths: ruby source "#{node['python']['url']}/#{version}/Python-#{version}.tar.bz2" By defining multiple paths for multiple locations: ruby source 'http://seapower/spring.png', 'http://seapower/has_sprung.png' By defining those same multiple paths as an array: ruby source ['http://seapower/spring.png', 'http://seapower/has_sprung.png'] When multiple paths are specified, Chef Infra Client will attempt to download the files in the order listed, stopping after the first successful download.

show_progress
Ruby Type: true, false | Default Value: false

Displays the progress of the file download.

ssl_verify_mode
Ruby Type: Symbol
Allowed Values: :verify_none, :verify_peer

Optional property to override SSL policy. If not specified, uses the SSL policy from config.rb.

New in Chef Infra Client 16.2

use_conditional_get
Ruby Type: true, false | Default Value: true

Enable conditional HTTP requests by using a conditional GET (with the If-Modified-Since header) or an opaque identifier (ETag). To use If-Modified-Since headers, use_last_modified must also be set to true. To use ETag headers, use_etag must also be set to true.

use_etag
Ruby Type: true, false | Default Value: true

Enable ETag headers. Set to false to disable ETag headers. To use this setting, use_conditional_get must also be set to true.

use_last_modified
Ruby Type: true, false | Default Value: true

Enable If-Modified-Since headers. Set to false to disable If-Modified-Since headers. To use this setting, use_conditional_get must also be set to true.

verify
Ruby Type: String, Block

A block or a string that returns true or false. A string, when true is executed as a system command.

A block is arbitrary Ruby defined within the resource block by using the verify property. When a block is true, Chef Infra Client will continue to update the file as appropriate.

For example, this should return true:

remote_file '/tmp/baz' do
  verify { 1 == 1 }
end

This should return true:

remote_file '/etc/nginx.conf' do
  verify 'nginx -t -c %{path}'
end

This should return true:

remote_file '/tmp/bar' do
  verify { 1 == 1}
end

And this should return true:

remote_file '/tmp/foo' do
  verify do |path|
    true
  end
end

Whereas, this should return false:

remote_file '/tmp/turtle' do
  verify '/usr/bin/false'
end

If a string or a block return false, the Chef Infra Client run will stop and an error is returned.

Atomic File Updates

Atomic updates are used with file-based resources to help ensure that file updates can be made when updating a binary or if disk space runs out.

Atomic updates are enabled by default. They can be managed globally using the file_atomic_update setting in the client.rb file. They can be managed for each resource using the atomic_update property that is available with the cookbook_file, file, remote_file, and template resources.

Note

On certain platforms, and after a file has been moved into place, Chef Infra Client may modify file permissions to support features specific to those platforms. On platforms with SELinux enabled, Chef Infra Client will fix up the security contexts after a file has been moved into the correct location by running the restorecon command. On the Microsoft Windows platform, Chef Infra Client will create files so that ACL inheritance works as expected.

Windows File Security

To support Windows security, the template, file, remote_file, cookbook_file, directory, and remote_directory resources support the use of inheritance and access control lists (ACLs) within recipes. Access Control Lists (ACLs)

The rights property can be used in a recipe to manage access control lists (ACLs), which allow permissions to be given to multiple users and groups. Use the rights property can be used as many times as necessary; Chef Infra Client will apply them to the file or directory as required. The syntax for the rights property is as follows:

rights permission, principal, option_type => value

where

permission

Use to specify which rights are granted to the principal. The possible values are: :read, :write, read_execute, :modify, :full_control, or an integer.

Integers used for permissions must match the following list FileSystemRights Enum fields.

These permissions are cumulative. If :write is specified, then it includes :read. If :full_control is specified, then it includes both :write and :read.

(For those who know the Windows API: :read corresponds to GENERIC_READ; :write corresponds to GENERIC_WRITE; :read_execute corresponds to GENERIC_READ and GENERIC_EXECUTE; :modify corresponds to GENERIC_WRITE, GENERIC_READ, GENERIC_EXECUTE, and DELETE; :full_control corresponds to GENERIC_ALL, which allows a user to change the owner and other metadata about a file.)

principal

Use to specify a group or user. The principal can be specified by either name or SID. When using name, this is identical to what is entered in the login box for Windows, such as user_name, domain\user_name, or user_name@fully_qualified_domain_name. When using a SID, you may use either the standard string representation of a SID (S-R-I-S-S) or one of the SDDL string constants. Chef Infra Client does not need to know if a principal is a user or a group.

option_type

A hash that contains advanced rights options. For example, the rights to a directory that only applies to the first level of children might look something like: rights :write, 'domain\group_name', :one_level_deep => true.

Possible option types:

:applies_to_children

Specify how permissions are applied to children. Possible values: true to inherit both child directories and files; false to not inherit any child directories or files; :containers_only to inherit only child directories (and not files); :objects_only to recursively inherit files (and not child directories).

:applies_to_self

Indicates whether a permission is applied to the parent directory. Possible values: true to apply to the parent directory or file and its children; false to not apply only to child directories and files.

:one_level_deep

Indicates the depth to which permissions will be applied. Possible values: true to apply only to the first level of children; false to apply to all children.

For example:

resource 'x.txt' do
  rights :read, 'S-1-1-0'
  rights :write, 'domain\group'
  rights :full_control, 'group_name_or_user_name'
  rights :full_control, 'user_name', applies_to_children: true
end

or:

rights :read, %w(Administrators Everyone)
rights :full_control, 'Users', applies_to_children: true
rights :write, 'Sally', applies_to_children: :containers_only, applies_to_self: false, one_level_deep: true

Some other important things to know when using the rights attribute:

  • Only inherited rights remain. All existing explicit rights on the object are removed and replaced.
  • If rights are not specified, nothing will be changed. Chef Infra Client does not clear out the rights on a file or directory if rights are not specified.
  • Changing inherited rights can be expensive. Windows will propagate rights to all children recursively due to inheritance. This is a normal aspect of Windows, so consider the frequency with which this type of action is necessary and take steps to control this type of action if performance is the primary consideration.

Use the deny_rights property to deny specific rights to specific users. The ordering is independent of using the rights property. For example, it doesn’t matter if rights are granted to everyone is placed before or after deny_rights :read, ['Julian', 'Lewis'], both Julian and Lewis will be unable to read the document. For example:

resource 'x.txt' do
  rights :read, 'Everyone'
  rights :write, 'domain\group'
  rights :full_control, 'group_name_or_user_name'
  rights :full_control, 'user_name', applies_to_children: true
  deny_rights :read, %w(Julian Lewis)
end

or:

deny_rights :full_control, ['Sally']
Inheritance

By default, a file or directory inherits rights from its parent directory. Most of the time this is the preferred behavior, but sometimes it may be necessary to take steps to more specifically control rights. The inherits property can be used to specifically tell Chef Infra Client to apply (or not apply) inherited rights from its parent directory.

For example, the following example specifies the rights for a directory:

directory 'C:\mordor' do
  rights :read, 'MORDOR\Minions'
  rights :full_control, 'MORDOR\Sauron'
end

and then the following example specifies how to use inheritance to deny access to the child directory:

directory 'C:\mordor\mount_doom' do
  rights :full_control, 'MORDOR\Sauron'
  inherits false # Sauron is the only person who should have any sort of access
end

If the deny_rights permission were to be used instead, something could slip through unless all users and groups were denied.

Another example also shows how to specify rights for a directory:

directory 'C:\mordor' do
  rights :read, 'MORDOR\Minions'
  rights :full_control, 'MORDOR\Sauron'
  rights :write, 'SHIRE\Frodo' # Who put that there I didn't put that there
end

but then not use the inherits property to deny those rights on a child directory:

directory 'C:\mordor\mount_doom' do
  deny_rights :read, 'MORDOR\Minions' # Oops, not specific enough
end

Because the inherits property is not specified, Chef Infra Client will default it to true, which will ensure that security settings for existing files remain unchanged.

Prevent Re-downloads

To prevent Chef Infra Client from re-downloading files that are already present on a node, use one of the following attributes in a recipe: use_conditional_get (default) or checksum.

  • The use_conditional_get attribute is the default behavior of Chef Infra Client. If the remote file is located on a server that supports ETag and/or If-Modified-Since headers, Chef Infra Client will use a conditional GET to determine if the file has been updated. If the file has been updated, Chef Infra Client will re-download the file.
  • The checksum attribute will ask Chef Infra Client to compare the checksum for the local file to the one at the remote location. If they match, Chef Infra Client will not re-download the file. Using a local checksum for comparison requires that the local checksum be the correct checksum.

The desired approach just depends on the desired workflow. For example, if a node requires a new file every day, using the checksum approach would require that the local checksum be updated and/or verified every day as well, to ensure that the local checksum was the correct one. Using a conditional GET in this scenario will greatly simplify the management required to ensure files are being updated accurately.

Access a remote UNC path on Windows

The remote_file resource on Windows supports accessing files from a remote SMB/CIFS share. The file name should be specified in the source property as a UNC path e.g. \myserver\myshare\mydirectory\myfile.txt. This allows access to the file at that path location even if the Chef Infra Client process identity does not have permission to access the file. Credentials for authenticating to the remote system can be specified using the remote_user, remote_domain, and remote_password properties when the user that Chef Infra Client is running does not have access to the remote file. See the “Properties” section for more details on these options.

Note: This is primarily for accessing remote files when the user that Chef Infra Client is running as does not have sufficient access, and alternative credentials need to be specified. If the user already has access, the credentials do not need to be specified. In a case where the local system and remote system are in the same domain, the remote_user and remote_password properties often do not need to be specified, as the user may already have access to the remote file share.

Examples:

Access a file from a different domain account:

remote_file 'E:/domain_test.txt' do
  source '\\myserver\myshare\mydirectory\myfile.txt'
  remote_domain 'domain'
  remote_user 'username'
  remote_password 'password'
end

OR

remote_file 'E:/domain_test.txt' do
  source '\\myserver\myshare\mydirectory\myfile.txt'
  remote_user 'domain\username'
  remote_password 'password'
end

Access a file using a local account on the remote machine:

remote_file 'E:/domain_test.txt' do
  source '\\myserver\myshare\mydirectory\myfile.txt'
  remote_domain '.'
  remote_user 'username'
  remote_password 'password'
end

OR

remote_file 'E:/domain_test.txt' do
  source '\\myserver\myshare\mydirectory\myfile.txt'
  remote_user '.\username'
  remote_password 'password'
end

Examples

The following examples demonstrate various approaches for using the remote_file resource in recipes:

Download a file without checking the checksum:

  remote_file '/tmp/remote.txt' do
    source 'https://example.org/remote.txt'
  end

Download a file with a checksum to validate:

  remote_file '/tmp/test_file' do
    source 'http://www.example.com/tempfiles/test_file'
    mode '0755'
    checksum '3a7dac00b1' # A SHA256 (or portion thereof) of the file.
  end

Download a file only if it’s not already present:

  remote_file '/tmp/remote.txt' do
    source 'https://example.org/remote.txt'
    checksum '3a7dac00b1' # A SHA256 (or portion thereof) of the file.
    action :create_if_missing
  end

Using HTTP Basic Authentication in Headers:

  remote_file '/tmp/remote.txt' do
    source 'https://example.org/remote.txt'
    headers('Authorization' => "Basic #{Base64.encode64("USERNAME_VALUE:PASSWORD_VALUE").delete("\n")}")
    checksum '3a7dac00b1' # A SHA256 (or portion thereof) of the file.
    action :create_if_missing
  end

Downloading a file to the Chef file cache dir for execution:

  remote_file '#{Chef::Config['file_cache_path']}/install.sh' do
    source 'https://example.org/install.sh'
    action :create_if_missing
  end

  execute '#{Chef::Config['file_cache_path']}/install.sh'

Specify advanced HTTP connection options including Net::HTTP (nethttp) options:

  remote_file '/tmp/remote.txt' do
    source 'https://example.org/remote.txt'
    http_options({
      http_retry_delay: 0,
      http_retry_count: 0,
      keepalives: false,
      nethttp: {
        continue_timeout: 5,
        max_retries: 5,
        read_timeout: 5,
        write_timeout: 5,
        ssl_timeout: 5,
      },
    })
  end
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