// Copyright 2020 The Bazel Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

syntax = "proto3";

package build.bazel.remote.asset.v1;

import "build/bazel/remote/execution/v2/remote_execution.proto";
import "google/api/annotations.proto";
import "google/protobuf/duration.proto";
import "google/protobuf/timestamp.proto";
import "google/rpc/status.proto";

option csharp_namespace = "Build.Bazel.Remote.Asset.v1";
option go_package = "remoteasset";
option java_multiple_files = true;
option java_outer_classname = "RemoteAssetProto";
option java_package = "build.bazel.remote.asset.v1";
option objc_class_prefix = "RA";

// The Remote Asset API provides a mapping from a URI and Qualifiers to
// Digests.  
//
// Multiple URIs may be used to refer to the same content.  For example, the
// same tarball may exist at multiple mirrors and thus be retrievable from
// multiple URLs.  When URLs are used, these should refer to actual content as
// Fetch service implementations may choose to fetch the content directly
// from the origin.  For example, the HEAD of a git repository's active branch
// can be referred to as:
//
//     uri: https://github.com/bazelbuild/remote-apis.git
//
// URNs may be used to strongly identify content, for instance by using the
// uuid namespace identifier: urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6.
// This is most applicable to named content that is Push'd, where the URN
// serves as an agreed-upon key, but carries no other inherent meaning.
//
// Service implementations may choose to support only URLs, only URNs for
// Push'd content, only other URIs for which the server and client agree upon
// semantics of, or any mixture of the above.

// Qualifiers are used to disambiguate or sub-select content that shares a URI.
// This may include specifying a particular commit or branch, in the case of
// URIs referencing a repository; they could also be used to specify a
// particular subdirectory of a repository or tarball. Qualifiers may also be
// used to ensure content matches what the client expects, even when there is
// no ambiguity to be had - for example, a qualifier specifying a checksum
// value.
//
// In cases where the semantics of the request are not immediately clear from
// the URL and/or qualifiers - e.g. dictated by URL scheme - it is recommended
// to use an additional qualifier to remove the ambiguity. The `resource_type`
// qualifier is recommended for this purpose.
//
// Qualifiers may be supplied in any order.
message Qualifier {
  // The "name" of the qualifier, for example "resource_type".
  // No separation is made between 'standard' and 'nonstandard'
  // qualifiers, in accordance with https://tools.ietf.org/html/rfc6648,
  // however implementers *SHOULD* take care to avoid ambiguity.
  string name = 1;

  // The "value" of the qualifier. Semantics will be dictated by the name.
  string value = 2;
}

// The Fetch service resolves or fetches assets referenced by URI and
// Qualifiers, returning a Digest for the content in 
// [ContentAddressableStorage][build.bazel.remote.execution.v2.ContentAddressableStorage].
//
// As with other services in the Remote Execution API, any call may return an
// error with a [RetryInfo][google.rpc.RetryInfo] error detail providing
// information about when the client should retry the request; clients SHOULD
// respect the information provided.
service Fetch {
  // Resolve or fetch referenced assets, making them available to the caller and
  // other consumers in the [ContentAddressableStorage][build.bazel.remote.execution.v2.ContentAddressableStorage].
  //
  // Servers *MAY* fetch content that they do not already have cached, for any
  // URLs they support.
  //
  // Servers *SHOULD* ensure that referenced files are present in the CAS at the
  // time of the response, and (if supported) that they will remain available
  // for a reasonable period of time. The lifetimes of the referenced blobs *SHOULD*
  // be increased if necessary and applicable.
  // In the event that a client receives a reference to content that is no
  // longer present, it *MAY* re-issue the request with
  // `oldest_content_accepted` set to a more recent timestamp than the original
  // attempt, to induce a re-fetch from origin.
  //
  // Servers *MAY* cache fetched content and reuse it for subsequent requests,
  // subject to `oldest_content_accepted`.
  //
  // Servers *MAY* support the complementary [Push][build.bazel.remote.asset.v1.Push]
  // API and allow content to be directly inserted for use in future fetch
  // responses.
  //
  // Servers *MUST* ensure Fetch'd content matches all the specified
  // qualifiers except in the case of previously Push'd resources, for which
  // the server *MAY* trust the pushing client to have set the qualifiers
  // correctly, without validation.
  //
  // Servers not implementing the complementary [Push][build.bazel.remote.asset.v1.Push]
  // API *MUST* reject requests containing qualifiers it does not support.
  //
  // Servers *MAY* transform assets as part of the fetch. For example a
  // tarball fetched by [FetchDirectory][build.bazel.remote.asset.v1.Fetch.FetchDirectory]
  // might be unpacked, or a Git repository
  // fetched by [FetchBlob][build.bazel.remote.asset.v1.Fetch.FetchBlob]
  // might be passed through `git-archive`.
  //
  // Errors handling the requested assets will be returned as gRPC Status errors
  // here; errors outside the server's control will be returned inline in the
  // `status` field of the response (see comment there for details).
  // The possible RPC errors include:
  // * `INVALID_ARGUMENT`: One or more arguments were invalid, such as a
  //   qualifier that is not supported by the server.
  // * `RESOURCE_EXHAUSTED`: There is insufficient quota of some resource to
  //   perform the requested operation. The client may retry after a delay.
  // * `UNAVAILABLE`: Due to a transient condition the operation could not be
  //   completed. The client should retry.
  // * `INTERNAL`: An internal error occurred while performing the operation.
  //   The client should retry.
  // * `DEADLINE_EXCEEDED`: The fetch could not be completed within the given
  //   RPC deadline. The client should retry for at least as long as the value
  //   provided in `timeout` field of the request.
  //
  // In the case of unsupported qualifiers, the server *SHOULD* additionally
  // send a [BadRequest][google.rpc.BadRequest] error detail where, for each
  // unsupported qualifier, there is a `FieldViolation` with a `field` of
  // `qualifiers.name` and a `description` of `"{qualifier}" not supported`
  // indicating the name of the unsupported qualifier.
  rpc FetchBlob(FetchBlobRequest) returns (FetchBlobResponse) {
    option (google.api.http) = { post: "/v1/{instance_name=**}/assets:fetchBlob" body: "*" };
  }
  rpc FetchDirectory(FetchDirectoryRequest) returns (FetchDirectoryResponse) {
    option (google.api.http) = { post: "/v1/{instance_name=**}/assets:fetchDirectory" body: "*" };
  }
}

// A request message for
// [Fetch.FetchBlob][build.bazel.remote.asset.v1.Fetch.FetchBlob].
message FetchBlobRequest {
  // The instance of the execution system to operate against. A server may
  // support multiple instances of the execution system (with their own workers,
  // storage, caches, etc.). The server MAY require use of this field to select
  // between them in an implementation-defined fashion, otherwise it can be
  // omitted.
  string instance_name = 1;

  // The timeout for the underlying fetch, if content needs to be retrieved from
  // origin.
  //
  // If unset, the server *MAY* apply an implementation-defined timeout.
  //
  // If set, and the user-provided timeout exceeds the RPC deadline, the server
  // *SHOULD* keep the fetch going after the RPC completes, to be made
  // available for future Fetch calls. The server may also enforce (via clamping
  // and/or an INVALID_ARGUMENT error) implementation-defined minimum and
  // maximum timeout values.
  //
  // If this timeout is exceeded on an attempt to retrieve content from origin
  // the client will receive DEADLINE_EXCEEDED in [FetchBlobResponse.status].
  google.protobuf.Duration timeout = 2;

  // The oldest content the client is willing to accept, as measured from the
  // time it was Push'd or when the underlying retrieval from origin was 
  // started.
  // Upon retries of Fetch requests that cannot be completed within a single
  // RPC, clients *SHOULD* provide the same value for subsequent requests as the
  // original, to simplify combining the request with the previous attempt.
  //
  // If unset, the client *SHOULD* accept content of any age.
  google.protobuf.Timestamp oldest_content_accepted = 3;

  // The URI(s) of the content to fetch. These may be resources that the server
  // can directly fetch from origin, in which case multiple URIs *SHOULD*
  // represent the same content available at different locations (such as an
  // origin and secondary mirrors). These may also be URIs for content known to
  // the server through other mechanisms, e.g. pushed via the [Push][build.bazel.remote.asset.v1.Push]
  // service.
  //
  // Clients *MUST* supply at least one URI. Servers *MAY* match any one of the
  // supplied URIs.
  repeated string uris = 4;

  // Qualifiers sub-specifying the content to fetch - see comments on
  // [Qualifier][build.bazel.remote.asset.v1.Qualifier].
  // The same qualifiers apply to all URIs.
  //
  // Specified qualifier names *MUST* be unique.
  repeated Qualifier qualifiers = 5;
}

// A response message for
// [Fetch.FetchBlob][build.bazel.remote.asset.v1.Fetch.FetchBlob].
message FetchBlobResponse {
  // If the status has a code other than `OK`, it indicates that the operation
  // was unable to be completed for reasons outside the servers' control.
  // The possible fetch errors include:
  // * `DEADLINE_EXCEEDED`: The operation could not be completed within the
  //   specified timeout.
  // * `NOT_FOUND`: The requested asset was not found at the specified location.
  // * `PERMISSION_DENIED`: The request was rejected by a remote server, or
  //   requested an asset from a disallowed origin.
  // * `ABORTED`: The operation could not be completed, typically due to a
  //   failed consistency check.
  google.rpc.Status status = 1;

  // The uri from the request that resulted in a successful retrieval, or from
  // which the error indicated in `status` was obtained.
  string uri = 2;

  // Any qualifiers known to the server and of interest to clients.
  repeated Qualifier qualifiers = 3;

  // A minimum timestamp the content is expected to be available through.
  // Servers *MAY* omit this field, if not known with confidence.
  google.protobuf.Timestamp expires_at = 4;

  // The result of the fetch, if the status had code `OK`.
  // The digest of the file's contents, available for download through the CAS.
  build.bazel.remote.execution.v2.Digest blob_digest = 5;
}

// A request message for
// [Fetch.FetchDirectory][build.bazel.remote.asset.v1.Fetch.FetchDirectory].
message FetchDirectoryRequest {
  // The instance of the execution system to operate against. A server may
  // support multiple instances of the execution system (with their own workers,
  // storage, caches, etc.). The server MAY require use of this field to select
  // between them in an implementation-defined fashion, otherwise it can be
  // omitted.
  string instance_name = 1;

  // The timeout for the underlying fetch, if content needs to be retrieved from
  // origin. This value is allowed to exceed the RPC deadline, in which case the
  // server *SHOULD* keep the fetch going after the RPC completes, to be made
  // available for future Fetch calls.
  //
  // If this timeout is exceeded on an attempt to retrieve content from origin
  // the client will receive DEADLINE_EXCEEDED in [FetchDirectoryResponse.status].
  google.protobuf.Duration timeout = 2;

  // The oldest content the client is willing to accept, as measured from the
  // time it was Push'd or when the underlying retrieval from origin was
  // started.
  // Upon retries of Fetch requests that cannot be completed within a single
  // RPC, clients *SHOULD* provide the same value for subsequent requests as the
  // original, to simplify combining the request with the previous attempt.
  //
  // If unset, the client *SHOULD* accept content of any age.
  google.protobuf.Timestamp oldest_content_accepted = 3;

  // The URI(s) of the content to fetch. These may be resources that the server
  // can directly fetch from origin, in which case multiple URIs *SHOULD*
  // represent the same content available at different locations (such as an
  // origin and secondary mirrors). These may also be URIs for content known to
  // the server through other mechanisms, e.g. pushed via the [Push][build.bazel.remote.asset.v1.Push]
  // service.
  //
  // Clients *MUST* supply at least one URI. Servers *MAY* match any one of the
  // supplied URIs.
  repeated string uris = 4;

  // Qualifiers sub-specifying the content to fetch - see comments on
  // [Qualifier][build.bazel.remote.asset.v1.Qualifier].
  // The same qualifiers apply to all URIs.
  //
  // Specified qualifier names *MUST* be unique.
  repeated Qualifier qualifiers = 5;
}

// A response message for
// [Fetch.FetchDirectory][build.bazel.remote.asset.v1.Fetch.FetchDirectory].
message FetchDirectoryResponse {
  // If the status has a code other than `OK`, it indicates that the operation
  // was unable to be completed for reasons outside the servers' control.
  // The possible fetch errors include:
  // * `DEADLINE_EXCEEDED`: The operation could not be completed within the
  //   specified timeout.
  // * `NOT_FOUND`: The requested asset was not found at the specified location.
  // * `PERMISSION_DENIED`: The request was rejected by a remote server, or
  //   requested an asset from a disallowed origin.
  // * `ABORTED`: The operation could not be completed, typically due to a
  //   failed consistency check.
  google.rpc.Status status = 1;

  // The uri from the request that resulted in a successful retrieval, or from
  // which the error indicated in `status` was obtained.
  string uri = 2;

  // Any qualifiers known to the server and of interest to clients.
  repeated Qualifier qualifiers = 3;

  // A minimum timestamp the content is expected to be available through.
  // Servers *MAY* omit this field, if not known with confidence.
  google.protobuf.Timestamp expires_at = 4;

  // The result of the fetch, if the status had code `OK`.
  // the root digest of a directory tree, suitable for fetching via
  // [ContentAddressableStorage.GetTree].
  build.bazel.remote.execution.v2.Digest root_directory_digest = 5;
}

// The Push service is complementary to the Fetch, and allows for
// associating contents of URLs to be returned in future Fetch API calls.
//
// As with other services in the Remote Execution API, any call may return an
// error with a [RetryInfo][google.rpc.RetryInfo] error detail providing
// information about when the client should retry the request; clients SHOULD
// respect the information provided.
service Push {
  // These APIs associate the identifying information of a resource, as
  // indicated by URI and optionally Qualifiers, with content available in the
  // CAS. For example, associating a repository url and a commit id with a
  // Directory Digest.
  //
  // Servers *SHOULD* only allow trusted clients to associate content, and *MAY*
  // only allow certain URIs to be pushed.
  //
  // Clients *MUST* ensure associated content is available in CAS prior to
  // pushing.
  //
  // Clients *MUST* ensure the Qualifiers listed correctly match the contents,
  // and Servers *MAY* trust these values without validation.
  // Fetch servers *MAY* require exact match of all qualifiers when returning
  // content previously pushed, or allow fetching content with only a subset of
  // the qualifiers specified on Push.
  //
  // Clients can specify expiration information that the server *SHOULD*
  // respect. Subsequent requests can be used to alter the expiration time.
  //
  // A minimal compliant Fetch implementation may support only Push'd content
  // and return `NOT_FOUND` for any resource that was not pushed first.
  // Alternatively, a compliant implementation may choose to not support Push
  // and only return resources that can be Fetch'd from origin.
  //
  // Errors will be returned as gRPC Status errors.
  // The possible RPC errors include:
  // * `INVALID_ARGUMENT`: One or more arguments to the RPC were invalid.
  // * `RESOURCE_EXHAUSTED`: There is insufficient quota of some resource to
  //   perform the requested operation. The client may retry after a delay.
  // * `UNAVAILABLE`: Due to a transient condition the operation could not be
  //   completed. The client should retry.
  // * `INTERNAL`: An internal error occurred while performing the operation.
  //   The client should retry.
  rpc PushBlob(PushBlobRequest) returns (PushBlobResponse) {
    option (google.api.http) = { post: "/v1/{instance_name=**}/assets:pushBlob" body: "*" };
  }

  rpc PushDirectory(PushDirectoryRequest) returns (PushDirectoryResponse) {
    option (google.api.http) = { post: "/v1/{instance_name=**}/assets:pushDirectory" body: "*" };
  }
}

// A request message for
// [Push.PushBlob][build.bazel.remote.asset.v1.Push.PushBlob].
message PushBlobRequest {
  // The instance of the execution system to operate against. A server may
  // support multiple instances of the execution system (with their own workers,
  // storage, caches, etc.). The server MAY require use of this field to select
  // between them in an implementation-defined fashion, otherwise it can be
  // omitted.
  string instance_name = 1;

  // The URI(s) of the content to associate. If multiple URIs are specified, the
  // pushed content will be available to fetch by specifying any of them.
  repeated string uris = 2;

  // Qualifiers sub-specifying the content that is being pushed - see comments
  // on [Qualifier][build.bazel.remote.asset.v1.Qualifier].
  // The same qualifiers apply to all URIs.
  repeated Qualifier qualifiers = 3;

  // A time after which this content should stop being returned via [FetchBlob][build.bazel.remote.asset.v1.Fetch.FetchBlob].
  // Servers *MAY* expire content early, e.g. due to storage pressure.
  google.protobuf.Timestamp expire_at = 4;

  // The blob to associate.
  build.bazel.remote.execution.v2.Digest blob_digest = 5;

  // Referenced blobs or directories that need to not expire before expiration
  // of this association, in addition to `blob_digest` itself.
  // These fields are hints - clients *MAY* omit them, and servers *SHOULD*
  // respect them, at the risk of increased incidents of Fetch responses
  // indirectly referencing unavailable blobs.
  repeated build.bazel.remote.execution.v2.Digest references_blobs = 6;
  repeated build.bazel.remote.execution.v2.Digest references_directories = 7;
}

// A response message for
// [Push.PushBlob][build.bazel.remote.asset.v1.Push.PushBlob].
message PushBlobResponse { /* empty */ }

// A request message for
// [Push.PushDirectory][build.bazel.remote.asset.v1.Push.PushDirectory].
message PushDirectoryRequest {
  // The instance of the execution system to operate against. A server may
  // support multiple instances of the execution system (with their own workers,
  // storage, caches, etc.). The server MAY require use of this field to select
  // between them in an implementation-defined fashion, otherwise it can be
  // omitted.
  string instance_name = 1;

  // The URI(s) of the content to associate. If multiple URIs are specified, the
  // pushed content will be available to fetch by specifying any of them.
  repeated string uris = 2;

  // Qualifiers sub-specifying the content that is being pushed - see comments
  // on [Qualifier][build.bazel.remote.asset.v1.Qualifier].
  // The same qualifiers apply to all URIs.
  repeated Qualifier qualifiers = 3;

  // A time after which this content should stop being returned via
  // [FetchDirectory][build.bazel.remote.asset.v1.Fetch.FetchDirectory].
  // Servers *MAY* expire content early, e.g. due to storage pressure.
  google.protobuf.Timestamp expire_at = 4;

  // Directory to associate
  build.bazel.remote.execution.v2.Digest root_directory_digest = 5;

  // Referenced blobs or directories that need to not expire before expiration
  // of this association, in addition to `root_directory_digest` itself.
  // These fields are hints - clients *MAY* omit them, and servers *SHOULD*
  // respect them, at the risk of increased incidents of Fetch responses
  // indirectly referencing unavailable blobs.
  repeated build.bazel.remote.execution.v2.Digest references_blobs = 6;
  repeated build.bazel.remote.execution.v2.Digest references_directories = 7;
}

// A response message for
// [Push.PushDirectory][build.bazel.remote.asset.v1.Push.PushDirectory].
message PushDirectoryResponse { /* empty */ }