aws-sdk-for-zig/src/aws.zig
2021-07-24 00:25:53 -07:00

290 lines
12 KiB
Zig

const std = @import("std");
const awshttp = @import("awshttp.zig");
const json = @import("json.zig");
const url = @import("url.zig");
const case = @import("case.zig");
const servicemodel = @import("servicemodel.zig");
const log = std.log.scoped(.aws);
pub const Options = struct {
region: []const u8 = "aws-global",
dualstack: bool = false,
};
/// Using this constant may blow up build times. Recommed using Services()
/// function directly, e.g. const services = Services(.{.sts, .ec2, .s3, .ddb}){};
pub const services = servicemodel.services;
/// Get a service model by importing specific services only. As an example:
/// const services = Services(.{.sts, .ec2, .s3, .ddb}){};
///
/// This will give you a constant with service data for sts, ec2, s3 and ddb only
pub const Services = servicemodel.Services;
pub const Aws = struct {
allocator: *std.mem.Allocator,
aws_http: awshttp.AwsHttp,
const Self = @This();
pub fn init(allocator: *std.mem.Allocator) Self {
return .{
.allocator = allocator,
.aws_http = awshttp.AwsHttp.init(allocator),
};
}
pub fn deinit(self: *Aws) void {
self.aws_http.deinit();
}
pub fn call(self: Self, comptime request: anytype, options: Options) !FullResponse(request) {
// every codegenned request object includes a metaInfo function to get
// pointers to service and action
const meta_info = request.metaInfo();
const service_meta = meta_info.service_metadata;
const action = meta_info.action;
log.debug("call: prefix {s}, sigv4 {s}, version {s}, action {s}", .{
service_meta.endpoint_prefix,
service_meta.sigv4_name,
service_meta.version,
action.action_name,
});
log.debug("proto: {s}", .{service_meta.aws_protocol});
// It seems as though there are 3 major branches of the 6 protocols.
// 1. query/ec2_query, which are identical until you get to complex
// structures. TBD if the shortcut we're taking for query to make
// it return json will work on EC2, but my guess is yes.
// 2. *json*: These three appear identical for input (possible difference
// for empty body serialization), but differ in error handling.
// We're not doing a lot of error handling here, though.
// 3. rest_xml: This is a one-off for S3, never used since
switch (service_meta.aws_protocol) {
.query, .ec2_query => return self.callQuery(request, service_meta, action, options),
.rest_json_1, .json_1_0, .json_1_1 => @compileError("REST Json, Json 1.0/1.1 protocol not yet supported"),
.rest_xml => @compileError("REST XML protocol not yet supported"),
}
}
// Call using query protocol. This is documented as an XML protocol, but
// throwing a JSON accept header seems to work. EC2Query is very simliar to
// Query, so we'll handle both here. Realistically we probably don't effectively
// handle lists and maps properly anyway yet, so we'll go for it and see
// where it breaks. PRs and/or failing test cases appreciated.
fn callQuery(self: Self, comptime request: anytype, service_meta: anytype, action: anytype, options: Options) !FullResponse(request) {
var buffer = std.ArrayList(u8).init(self.allocator);
defer buffer.deinit();
const writer = buffer.writer();
try url.encode(request, writer, .{
.field_name_transformer = &queryFieldTransformer,
.allocator = self.allocator,
});
const continuation = if (buffer.items.len > 0) "&" else "";
const query = if (service_meta.aws_protocol == .query)
try std.fmt.allocPrint(self.allocator, "", .{})
else // EC2
try std.fmt.allocPrint(self.allocator, "?Action={s}&Version={s}", .{
action.action_name,
service_meta.version,
});
defer self.allocator.free(query);
const body = if (service_meta.aws_protocol == .query)
try std.fmt.allocPrint(self.allocator, "Action={s}&Version={s}{s}{s}", .{
action.action_name,
service_meta.version,
continuation,
buffer.items,
})
else // EC2
try std.fmt.allocPrint(self.allocator, "{s}", .{buffer.items});
defer self.allocator.free(body);
const FullR = FullResponse(request);
const response = try self.aws_http.callApi(
service_meta.endpoint_prefix,
.{
.body = body,
.query = query,
},
.{
.region = options.region,
.dualstack = options.dualstack,
.sigv4_service_name = service_meta.sigv4_name,
},
);
// TODO: Can response handling be reused?
defer response.deinit();
if (response.response_code != 200) {
log.err("call failed! return status: {d}", .{response.response_code});
log.err("Request Query:\n |{s}\n", .{query});
log.err("Request Body:\n |{s}\n", .{body});
log.err("Response Headers:\n", .{});
for (response.headers) |h|
log.err("\t{s}:{s}\n", .{ h.name, h.value });
log.err("Response Body:\n |{s}", .{response.body});
return error.HttpFailure;
}
// EC2 ignores our accept type, but technically query protocol only
// returns XML as well. So, we'll ignore the protocol here and just
// look at the return type
var isJson: bool = undefined;
for (response.headers) |h| {
if (std.mem.eql(u8, "Content-Type", h.name)) {
if (std.mem.startsWith(u8, h.value, "application/json")) {
isJson = true;
} else if (std.mem.startsWith(u8, h.value, "text/xml")) {
isJson = false;
} else {
log.err("Unexpected content type: {s}", .{h.value});
return error.UnexpectedContentType;
}
break;
}
}
// TODO: Handle XML
if (!isJson) return error.XmlUnimplemented;
var stream = json.TokenStream.init(response.body);
const parser_options = json.ParseOptions{
.allocator = self.allocator,
.allow_camel_case_conversion = true, // new option
.allow_snake_case_conversion = true, // new option
.allow_unknown_fields = true, // new option. Cannot yet handle non-struct fields though
.allow_missing_fields = false, // new option. Cannot yet handle non-struct fields though
};
const SResponse = ServerResponse(request);
const parsed_response = json.parse(SResponse, &stream, parser_options) catch |e| {
log.err(
\\Call successful, but unexpected response from service.
\\This could be the result of a bug or a stale set of code generated
\\service models. Response from server:
\\
\\{s}
\\
, .{response.body});
return e;
};
// Grab the first (and only) object from the server. Server shape expected to be:
// { ActionResponse: {ActionResult: {...}, ResponseMetadata: {...} } }
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
// Next line of code pulls this portion
//
//
// And the response property below will pull whatever is the ActionResult object
// We can grab index [0] as structs are guaranteed by zig to be returned in the order
// declared, and we're declaring in that order in ServerResponse().
const real_response = @field(parsed_response, @typeInfo(SResponse).Struct.fields[0].name);
return FullR{
.response = @field(real_response, @typeInfo(@TypeOf(real_response)).Struct.fields[0].name),
.response_metadata = .{
.request_id = real_response.ResponseMetadata.RequestId,
},
.parser_options = parser_options,
.raw_parsed = parsed_response,
};
}
};
fn ServerResponse(comptime request: anytype) type {
const T = Response(request);
const action = request.metaInfo().action;
// NOTE: The non-standard capitalization here is used as a performance
// enhancement and to reduce allocations in json.zig. These fields are
// not (nor are they ever intended to be) exposed outside this codebase
const ResponseMetadata = struct {
RequestId: []u8,
};
const Result = @Type(.{
.Struct = .{
.layout = .Auto,
.fields = &[_]std.builtin.TypeInfo.StructField{
.{
.name = action.action_name ++ "Result",
.field_type = T,
.default_value = null,
.is_comptime = false,
.alignment = 0,
},
.{
.name = "ResponseMetadata",
.field_type = ResponseMetadata,
.default_value = null,
.is_comptime = false,
.alignment = 0,
},
},
.decls = &[_]std.builtin.TypeInfo.Declaration{},
.is_tuple = false,
},
});
return @Type(.{
.Struct = .{
.layout = .Auto,
.fields = &[_]std.builtin.TypeInfo.StructField{
.{
.name = action.action_name ++ "Response",
.field_type = Result,
.default_value = null,
.is_comptime = false,
.alignment = 0,
},
},
.decls = &[_]std.builtin.TypeInfo.Declaration{},
.is_tuple = false,
},
});
}
fn FullResponse(comptime request: anytype) type {
return struct {
response: Response(request),
response_metadata: struct {
request_id: []u8,
},
parser_options: json.ParseOptions,
raw_parsed: ServerResponse(request),
const Self = @This();
pub fn deinit(self: Self) void {
json.parseFree(ServerResponse(request), self.raw_parsed, self.parser_options);
}
};
}
fn Response(comptime request: anytype) type {
return request.metaInfo().action.Response;
}
fn queryFieldTransformer(field_name: []const u8, encoding_options: url.EncodingOptions) anyerror![]const u8 {
return try case.snakeToPascal(encoding_options.allocator.?, field_name);
}
// Use for debugging json responses of specific requests
// test "dummy request" {
// const allocator = std.testing.allocator;
// const svs = Services(.{.sts}){};
// const request = svs.sts.get_session_token.Request{
// .duration_seconds = 900,
// };
// const FullR = FullResponse(request);
// const response =
// var stream = json.TokenStream.init(response);
//
// const parser_options = json.ParseOptions{
// .allocator = allocator,
// .allow_camel_case_conversion = true, // new option
// .allow_snake_case_conversion = true, // new option
// .allow_unknown_fields = true, // new option. Cannot yet handle non-struct fields though
// .allow_missing_fields = false, // new option. Cannot yet handle non-struct fields though
// };
// const SResponse = ServerResponse(request);
// const r = try json.parse(SResponse, &stream, parser_options);
// json.parseFree(SResponse, r, parser_options);
// }