forked from etc/pineapple-src
59 lines
2.3 KiB
Markdown
59 lines
2.3 KiB
Markdown
|
# Asset Caching
|
||
|
|
|
||
|
|
**The latest version of this documentation is available on [GitHub](https://github.com/Microsoft/vcpkg/tree/master/docs/users/assetcaching.md).**
|
||
|
|
|
||
|
|
**Experimental feature: this may change or be removed at any time**
|
||
|
|
|
||
|
|
Vcpkg can utilize mirrors to cache downloaded assets, ensuring continued operation even if the original source changes
|
||
|
|
or disappears.
|
||
|
|
|
||
|
|
In-tool help is available via `vcpkg help assetcaching`.
|
||
|
|
|
||
|
|
## Configuration
|
||
|
|
|
||
|
|
Asset caching can be configured by setting the environment variable `X_VCPKG_ASSET_SOURCES` to a semicolon-delimited
|
||
|
|
list of source strings. Characters can be escaped using backtick (\`).
|
||
|
|
|
||
|
|
### Valid source strings
|
||
|
|
|
||
|
|
The `<rw>` optional parameter for certain strings controls how they will be accessed. It can be specified as `read`,
|
||
|
|
`write`, or `readwrite` and defaults to `read`.
|
||
|
|
|
||
|
|
#### `clear`
|
||
|
|
|
||
|
|
Syntax: `clear`
|
||
|
|
|
||
|
|
Removes all previous sources
|
||
|
|
|
||
|
|
#### `x-azurl`
|
||
|
|
|
||
|
|
Syntax: `x-azurl,<url>[,<sas>[,<rw>]]`
|
||
|
|
|
||
|
|
Adds an Azure Blob Storage source, optionally using Shared Access Signature validation. URL should include the container
|
||
|
|
path and be terminated with a trailing `/`. SAS, if defined, should be prefixed with a `?`. Non-Azure servers will also
|
||
|
|
work if they respond to GET and PUT requests of the form: `<url><sha512><sas>`. As an example, if you set
|
||
|
|
`X_VCPKG_ASSET_SOURCES` to `x-azurl,https://mydomain.com/vcpkg/,token=abc123,readwrite` your server should respond to
|
||
|
|
`GET` and `PUT` requests of the form `https://mydomain.com/vcpkg/<sha512>?token=abc123`.
|
||
|
|
|
||
|
|
You can also use the filesystem (e.g. a network drive) via `file://` as asset cache. For example you then set
|
||
|
|
`X_VCPKG_ASSET_SOURCES` to `x-azurl,file:///Z:/vcpkg/assetcache/,,readwrite` when you have a network folder mounted at
|
||
|
|
`Z:/`.
|
||
|
|
|
||
|
|
The workflow of this asset source is:
|
||
|
|
|
||
|
|
1. Attemp to read from the mirror
|
||
|
|
2. (If step 1 failed) Read from the original url
|
||
|
|
3. (If step 2 succeeded) Write back to the mirror
|
||
|
|
|
||
|
|
You can enable/disable steps 1 and 3 via the [`<rw>`](#valid-source-strings) specifier and you can disable step 2 via
|
||
|
|
`x-block-origin` below.
|
||
|
|
|
||
|
|
See also the [binary caching documentation for Azure Blob Storage](binarycaching.md#azure-blob-storage-experimental) for
|
||
|
|
more information on how to set up an `x-azurl` source.
|
||
|
|
|
||
|
|
#### `x-block-origin`
|
||
|
|
|
||
|
|
Syntax: `x-block-origin`
|
||
|
|
|
||
|
|
Disables use of the original URLs in case the mirror does not have the file available.
|