http repository rules

The following functions can be loaded from @bazel_tools//tools/build_defs/repo:http.bzl.

Rules for downloading files and archives over HTTP.

Setup

To use these rules, load them in your WORKSPACE file as follows:

load(
    "@bazel_tools//tools/build_defs/repo:http.bzl",
    "http_archive",
    "http_file",
    "http_jar",
)

These rules are improved versions of the native http rules and will eventually replace the native rules.

http_archive

http_archive(name, add_prefix, auth_patterns, build_file, build_file_content, canonical_id,
             integrity, netrc, patch_args, patch_cmds, patch_cmds_win, patch_tool, patches,
             remote_patch_strip, remote_patches, repo_mapping, sha256, strip_prefix, type, url, urls,
             workspace_file, workspace_file_content)

Downloads a Bazel repository as a compressed archive file, decompresses it, and makes its targets available for binding.

It supports the following file extensions: "zip", "jar", "war", "aar", "tar", "tar.gz", "tgz", "tar.xz", "txz", "tar.zst", "tzst", tar.bz2, "ar", or "deb".

Examples: Suppose the current repository contains the source code for a chat program, rooted at the directory ~/chat-app. It needs to depend on an SSL library which is available from http://example.com/openssl.zip. This .zip file contains the following directory structure:

  WORKSPACE
  src/
    openssl.cc
    openssl.h

In the local repository, the user creates a openssl.BUILD file which contains the following target definition:

  cc_library(
      name = "openssl-lib",
      srcs = ["src/openssl.cc"],
      hdrs = ["src/openssl.h"],
  )

Targets in the ~/chat-app repository can depend on this target if the following lines are added to ~/chat-app/WORKSPACE:

  load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

  http_archive(
      name = "my_ssl",
      url = "http://example.com/openssl.zip",
      sha256 = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
      build_file = "@//:openssl.BUILD",
  )

Then targets would specify @my_ssl//:openssl-lib as a dependency.

Attributes

name Name; required

A unique name for this repository.

add_prefix String; optional

Destination directory relative to the repository directory. The archive will be unpacked into this directory, after applying `strip_prefix` (if any) to the file paths within the archive. For example, file `foo-1.2.3/src/foo.h` will be unpacked to `bar/src/foo.h` if `add_prefix = "bar"` and `strip_prefix = "foo-1.2.3"`.

auth_patterns Dictionary: String -> String; optional

An optional dict mapping host names to custom authorization patterns. If a URL's host name is present in this dict the value will be used as a pattern when generating the authorization header for the http request. This enables the use of custom authorization schemes used in a lot of common cloud storage providers. The pattern currently supports 2 tokens: <login> and <password>, which are replaced with their equivalent value in the netrc file for the same host name. After formatting, the result is set as the value for the Authorization field of the HTTP request. Example attribute and netrc for a http download to an oauth2 enabled API using a bearer token: 

auth_patterns = {
    "storage.cloudprovider.com": "Bearer <password>"
}
netrc: 
machine storage.cloudprovider.com
        password RANDOM-TOKEN
The final HTTP request would have the following header: 
Authorization: Bearer RANDOM-TOKEN

build_file Label; optional

The file to use as the BUILD file for this repository.This attribute is an absolute label (use '@//' for the main repo). The file does not need to be named BUILD, but can be (something like BUILD.new-repo-name may work well for distinguishing it from the repository's actual BUILD files. Either build_file or build_file_content can be specified, but not both.

build_file_content String; optional

The content for the BUILD file for this repository. Either build_file or build_file_content can be specified, but not both.

canonical_id String; optional

A canonical ID of the file downloaded. If specified and non-empty, Bazel will not take the file from cache, unless it was added to the cache by a request with the same canonical ID. If unspecified or empty, Bazel by default uses the URLs of the file as the canonical ID. This helps catch the common mistake of updating the URLs without also updating the hash, resulting in builds that succeed locally but fail on machines without the file in the cache. This behavior can be disabled with --repo_env=BAZEL_HTTP_RULES_URLS_AS_DEFAULT_CANONICAL_ID=0.

integrity String; optional

Expected checksum in Subresource Integrity format of the file downloaded. This must match the checksum of the file downloaded. _It is a security risk to omit the checksum as remote files can change._ At best omitting this field will make your build non-hermetic. It is optional to make development easier but either this attribute or `sha256` should be set before shipping.

netrc String; optional

Location of the .netrc file to use for authentication

patch_args List of strings; optional

The arguments given to the patch tool. Defaults to -p0, however -p1 will usually be needed for patches generated by git. If multiple -p arguments are specified, the last one will take effect.If arguments other than -p are specified, Bazel will fall back to use patch command line tool instead of the Bazel-native patch implementation. When falling back to patch command line tool and patch_tool attribute is not specified, `patch` will be used. This only affects patch files in the `patches` attribute.

patch_cmds List of strings; optional

Sequence of Bash commands to be applied on Linux/Macos after patches are applied.

patch_cmds_win List of strings; optional

Sequence of Powershell commands to be applied on Windows after patches are applied. If this attribute is not set, patch_cmds will be executed on Windows, which requires Bash binary to exist.

patch_tool String; optional

The patch(1) utility to use. If this is specified, Bazel will use the specified patch tool instead of the Bazel-native patch implementation.

patches List of labels; optional

A list of files that are to be applied as patches after extracting the archive. By default, it uses the Bazel-native patch implementation which doesn't support fuzz match and binary patch, but Bazel will fall back to use patch command line tool if `patch_tool` attribute is specified or there are arguments other than `-p` in `patch_args` attribute.

remote_patch_strip Integer; optional

The number of leading slashes to be stripped from the file name in the remote patches.

remote_patches Dictionary: String -> String; optional

A map of patch file URL to its integrity value, they are applied after extracting the archive and before applying patch files from the `patches` attribute. It uses the Bazel-native patch implementation, you can specify the patch strip number with `remote_patch_strip`

repo_mapping Dictionary: String -> String; required

A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.

For example, an entry `"@foo": "@bar"` declares that, for any time this repository depends on `@foo` (such as a dependency on `@foo//some:target`, it should actually resolve that dependency within globally-declared `@bar` (`@bar//some:target`).

sha256 String; optional

The expected SHA-256 of the file downloaded. This must match the SHA-256 of the file downloaded. _It is a security risk to omit the SHA-256 as remote files can change._ At best omitting this field will make your build non-hermetic. It is optional to make development easier but either this attribute or `integrity` should be set before shipping.

strip_prefix String; optional

A directory prefix to strip from the extracted files. Many archives contain a top-level directory that contains all of the useful files in archive. Instead of needing to specify this prefix over and over in the `build_file`, this field can be used to strip it from all of the extracted files. For example, suppose you are using `foo-lib-latest.zip`, which contains the directory `foo-lib-1.2.3/` under which there is a `WORKSPACE` file and are `src/`, `lib/`, and `test/` directories that contain the actual code you wish to build. Specify `strip_prefix = "foo-lib-1.2.3"` to use the `foo-lib-1.2.3` directory as your top-level directory. Note that if there are files outside of this directory, they will be discarded and inaccessible (e.g., a top-level license file). This includes files/directories that start with the prefix but are not in the directory (e.g., `foo-lib-1.2.3.release-notes`). If the specified prefix does not match a directory in the archive, Bazel will return an error.

type String; optional

The archive type of the downloaded file. By default, the archive type is determined from the file extension of the URL. If the file has no extension, you can explicitly specify one of the following: `"zip"`, `"jar"`, `"war"`, `"aar"`, `"tar"`, `"tar.gz"`, `"tgz"`, `"tar.xz"`, `"txz"`, `"tar.zst"`, `"tzst"`, `"tar.bz2"`, `"ar"`, or `"deb"`.

url String; optional

A URL to a file that will be made available to Bazel. This must be a file, http or https URL. Redirections are followed. Authentication is not supported. More flexibility can be achieved by the urls parameter that allows to specify alternative URLs to fetch from.

urls List of strings; optional

A list of URLs to a file that will be made available to Bazel. Each entry must be a file, http or https URL. Redirections are followed. Authentication is not supported. URLs are tried in order until one succeeds, so you should list local mirrors first. If all downloads fail, the rule will fail.

workspace_file Label; optional

The file to use as the `WORKSPACE` file for this repository. Either `workspace_file` or `workspace_file_content` can be specified, or neither, but not both.

workspace_file_content String; optional

The content for the WORKSPACE file for this repository. Either `workspace_file` or `workspace_file_content` can be specified, or neither, but not both.

http_file

http_file(name, auth_patterns, canonical_id, downloaded_file_path, executable, integrity, netrc,
          repo_mapping, sha256, url, urls)

Downloads a file from a URL and makes it available to be used as a file group.

Examples: Suppose you need to have a debian package for your custom rules. This package is available from http://example.com/package.deb. Then you can add to your WORKSPACE file:

  load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_file")

  http_file(
      name = "my_deb",
      url = "http://example.com/package.deb",
      sha256 = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
  )

Targets would specify @my_deb//file as a dependency to depend on this file.

Attributes

name Name; required

A unique name for this repository.

auth_patterns Dictionary: String -> String; optional

An optional dict mapping host names to custom authorization patterns. If a URL's host name is present in this dict the value will be used as a pattern when generating the authorization header for the http request. This enables the use of custom authorization schemes used in a lot of common cloud storage providers. The pattern currently supports 2 tokens: <login> and <password>, which are replaced with their equivalent value in the netrc file for the same host name. After formatting, the result is set as the value for the Authorization field of the HTTP request. Example attribute and netrc for a http download to an oauth2 enabled API using a bearer token: 

auth_patterns = {
    "storage.cloudprovider.com": "Bearer <password>"
}
netrc: 
machine storage.cloudprovider.com
        password RANDOM-TOKEN
The final HTTP request would have the following header: 
Authorization: Bearer RANDOM-TOKEN

canonical_id String; optional

A canonical ID of the file downloaded. If specified and non-empty, Bazel will not take the file from cache, unless it was added to the cache by a request with the same canonical ID. If unspecified or empty, Bazel by default uses the URLs of the file as the canonical ID. This helps catch the common mistake of updating the URLs without also updating the hash, resulting in builds that succeed locally but fail on machines without the file in the cache. This behavior can be disabled with --repo_env=BAZEL_HTTP_RULES_URLS_AS_DEFAULT_CANONICAL_ID=0.

downloaded_file_path String; optional

Path assigned to the file downloaded

executable Boolean; optional

If the downloaded file should be made executable.

integrity String; optional

Expected checksum in Subresource Integrity format of the file downloaded. This must match the checksum of the file downloaded. _It is a security risk to omit the checksum as remote files can change._ At best omitting this field will make your build non-hermetic. It is optional to make development easier but either this attribute or `sha256` should be set before shipping.

netrc String; optional

Location of the .netrc file to use for authentication

repo_mapping Dictionary: String -> String; required

A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.

For example, an entry `"@foo": "@bar"` declares that, for any time this repository depends on `@foo` (such as a dependency on `@foo//some:target`, it should actually resolve that dependency within globally-declared `@bar` (`@bar//some:target`).

sha256 String; optional

The expected SHA-256 of the file downloaded. This must match the SHA-256 of the file downloaded. _It is a security risk to omit the SHA-256 as remote files can change._ At best omitting this field will make your build non-hermetic. It is optional to make development easier but should be set before shipping.

url String; optional

A URL to a file that will be made available to Bazel. This must be a file, http or https URL. Redirections are followed. Authentication is not supported. More flexibility can be achieved by the urls parameter that allows to specify alternative URLs to fetch from.

urls List of strings; optional

A list of URLs to a file that will be made available to Bazel. Each entry must be a file, http or https URL. Redirections are followed. Authentication is not supported. URLs are tried in order until one succeeds, so you should list local mirrors first. If all downloads fail, the rule will fail.

http_jar

http_jar(name, auth_patterns, canonical_id, downloaded_file_name, integrity, netrc, repo_mapping,
         sha256, url, urls)

Downloads a jar from a URL and makes it available as java_import

Downloaded files must have a .jar extension.

Examples: Suppose the current repository contains the source code for a chat program, rooted at the directory ~/chat-app. It needs to depend on an SSL library which is available from http://example.com/openssl-0.2.jar.

Targets in the ~/chat-app repository can depend on this target if the following lines are added to ~/chat-app/WORKSPACE:

  load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_jar")

  http_jar(
      name = "my_ssl",
      url = "http://example.com/openssl-0.2.jar",
      sha256 = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
  )

Targets would specify @my_ssl//jar as a dependency to depend on this jar.

You may also reference files on the current system (localhost) by using "file:///path/to/file" if you are on Unix-based systems. If you're on Windows, use "file:///c:/path/to/file". In both examples, note the three slashes (/) -- the first two slashes belong to file:// and the third one belongs to the absolute path to the file.

Attributes

name Name; required

A unique name for this repository.

auth_patterns Dictionary: String -> String; optional

An optional dict mapping host names to custom authorization patterns. If a URL's host name is present in this dict the value will be used as a pattern when generating the authorization header for the http request. This enables the use of custom authorization schemes used in a lot of common cloud storage providers. The pattern currently supports 2 tokens: <login> and <password>, which are replaced with their equivalent value in the netrc file for the same host name. After formatting, the result is set as the value for the Authorization field of the HTTP request. Example attribute and netrc for a http download to an oauth2 enabled API using a bearer token: 

auth_patterns = {
    "storage.cloudprovider.com": "Bearer <password>"
}
netrc: 
machine storage.cloudprovider.com
        password RANDOM-TOKEN
The final HTTP request would have the following header: 
Authorization: Bearer RANDOM-TOKEN

canonical_id String; optional

A canonical ID of the file downloaded. If specified and non-empty, Bazel will not take the file from cache, unless it was added to the cache by a request with the same canonical ID. If unspecified or empty, Bazel by default uses the URLs of the file as the canonical ID. This helps catch the common mistake of updating the URLs without also updating the hash, resulting in builds that succeed locally but fail on machines without the file in the cache. This behavior can be disabled with --repo_env=BAZEL_HTTP_RULES_URLS_AS_DEFAULT_CANONICAL_ID=0.

downloaded_file_name String; optional

Filename assigned to the jar downloaded

integrity String; optional

Expected checksum in Subresource Integrity format of the file downloaded. This must match the checksum of the file downloaded. _It is a security risk to omit the checksum as remote files can change._ At best omitting this field will make your build non-hermetic. It is optional to make development easier but either this attribute or `sha256` should be set before shipping.

netrc String; optional

Location of the .netrc file to use for authentication

repo_mapping Dictionary: String -> String; required

A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.

For example, an entry `"@foo": "@bar"` declares that, for any time this repository depends on `@foo` (such as a dependency on `@foo//some:target`, it should actually resolve that dependency within globally-declared `@bar` (`@bar//some:target`).

sha256 String; optional

The expected SHA-256 of the file downloaded. This must match the SHA-256 of the file downloaded. _It is a security risk to omit the SHA-256 as remote files can change._ At best omitting this field will make your build non-hermetic. It is optional to make development easier but either this attribute or `integrity` should be set before shipping.

url String; optional

A URL to a file that will be made available to Bazel. This must be a file, http or https URL. Redirections are followed. Authentication is not supported. More flexibility can be achieved by the urls parameter that allows to specify alternative URLs to fetch from. The URL must end in `.jar`.

urls List of strings; optional

A list of URLs to a file that will be made available to Bazel. Each entry must be a file, http or https URL. Redirections are followed. Authentication is not supported. URLs are tried in order until one succeeds, so you should list local mirrors first. If all downloads fail, the rule will fail. All URLs must end in `.jar`.