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cleanup and refactoring. Addressed TODO related to comptime eval

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This commit is contained in:
Emil Lerch 2022-05-29 12:49:02 -07:00
parent 03f7228662
commit c531164cfa
Signed by: lobo
GPG Key ID: A7B62D657EF764F8
1 changed files with 183 additions and 99 deletions
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src/aws.zig
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@ -239,21 +239,11 @@ pub fn Request(comptime action: anytype) type {
}
const isJson = try isJsonResponse(response.headers);
if (!isJson) return try xmlReturn(options, response);
return try jsonReturn(aws_request, options, response);
}
const SResponse = if (Self.service_meta.aws_protocol != .query)
action.Response
else
ServerResponse(action);
const NullType: type = u0; // This is a small hack, yes...
const SRawResponse = if (Self.service_meta.aws_protocol != .query and
std.meta.fields(SResponse).len == 1)
std.meta.fields(SResponse)[0].field_type
else
NullType;
fn jsonReturn(aws_request: awshttp.HttpRequest, options: Options, response: awshttp.HttpResult) !FullResponseType {
const parser_options = json.ParseOptions{
.allocator = options.client.allocator,
.allow_camel_case_conversion = true, // new option
@ -261,7 +251,10 @@ pub fn Request(comptime action: anytype) type {
.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
};
if (std.meta.fields(SResponse).len == 0) // We don't care about the body if there are no fields
// If the expected result has no fields, there's no sense in
// doing any more work. Let's bail early
if (std.meta.fields(action.Response).len == 0) // We don't care about the body if there are no fields
// Do we care if an unexpected body comes in?
return FullResponseType{
.response = .{},
@ -272,76 +265,45 @@ pub fn Request(comptime action: anytype) type {
.raw_parsed = .{ .raw = .{} },
};
var stream = json.TokenStream.init(response.body);
// Get our possible response types. There are 3:
//
// 1. A result wrapped with metadata like request ID. This is ServerResponse(action)
// 2. A "Normal" result, which starts with { "MyActionResponse": {...} }
// 3. A "Raw" result, which is simply {...} without decoration
const response_types = jsonResponseTypesForAction();
const start = std.mem.indexOf(u8, response.body, "\"") orelse 0; // Should never be 0
if (start == 0) log.warn("Response body missing json key?!", .{});
var end = std.mem.indexOf(u8, response.body[start + 1 ..], "\"") orelse 0;
if (end == 0) log.warn("Response body only has one double quote?!", .{});
end = end + start + 1;
// Parse the server data. Function will determine which of the three
// responses we have, and do the right thing
const parsed_data = try parseJsonData(response_types, response.body, options, parser_options);
defer parsed_data.deinit();
const key = response.body[start + 1 .. end];
log.debug("First json key: {s}", .{key});
const foundNormalJsonResponse = std.mem.eql(u8, key, action.action_name ++ "Response");
const parsed_response_ptr = blk: {
if (SRawResponse == NullType or foundNormalJsonResponse)
break :blk &(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.
\\
\\Model Type: {s}
\\
\\Response from server:
\\
\\{s}
\\
, .{ SResponse, response.body });
return e;
});
const parsed_response = parsed_data.parsed_response_ptr.*;
log.debug("Appears server has provided a raw response", .{});
const ptr = try options.client.allocator.create(SResponse);
@field(ptr.*, std.meta.fields(SResponse)[0].name) =
json.parse(SRawResponse, &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.
\\
\\Model Type: {s}
\\
\\Response from server:
\\
\\{s}
\\
, .{ SResponse, response.body });
return e;
if (response_types.NormalResponse == ServerResponse(action)) {
// This should only apply to query results, but we're in comptime
// type land, so the only thing that matters is whether our
// response is a ServerResponse
//
// Grab the first (and only) object from the data. 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(response_types.NormalResponse).Struct.fields[0].name);
return FullResponseType{
.response = @field(real_response, @typeInfo(@TypeOf(real_response)).Struct.fields[0].name),
.response_metadata = .{
.request_id = try options.client.allocator.dupe(u8, real_response.ResponseMetadata.RequestId),
},
.parser_options = .{ .json = parser_options },
.raw_parsed = .{ .server = parsed_response },
};
break :blk ptr;
};
// This feels like it should result in a use after free, but it
// seems to be working?
defer if (!(SRawResponse == NullType or foundNormalJsonResponse))
options.client.allocator.destroy(parsed_response_ptr);
const parsed_response = parsed_response_ptr.*;
// TODO: Figure out this hack
// the code setting the response about 10 lines down will trigger
// an error because the first field may not be a struct when
// XML processing is happening above, which we only know at runtime.
//
// We could simply force .ec2_query and .rest_xml above rather than
// isJson, but it would be nice to automatically support json if
// these services start returning that like we'd like them to.
//
// Otherwise, the compiler gets down here thinking this will be
// processed. If it is, then we have a problem when the field name
// may not be a struct.
if (Self.service_meta.aws_protocol != .query or Self.service_meta.aws_protocol == .ec2_query) {
} else {
// Conditions 2 or 3 (no wrapping)
return FullResponseType{
.response = parsed_response,
.response_metadata = .{
@ -351,25 +313,6 @@ pub fn Request(comptime action: anytype) type {
.raw_parsed = .{ .raw = parsed_response },
};
}
// 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 FullResponseType{
.response = @field(real_response, @typeInfo(@TypeOf(real_response)).Struct.fields[0].name),
.response_metadata = .{
.request_id = try options.client.allocator.dupe(u8, real_response.ResponseMetadata.RequestId),
},
.parser_options = .{ .json = parser_options },
.raw_parsed = .{ .server = parsed_response },
};
}
fn xmlReturn(options: Options, result: awshttp.HttpResult) !FullResponseType {
@ -456,9 +399,150 @@ pub fn Request(comptime action: anytype) type {
.raw_parsed = .{ .xml = parsed },
};
}
const ServerResponseTypes = struct {
NormalResponse: type,
RawResponse: type,
isRawPossible: bool,
};
fn jsonResponseTypesForAction() ServerResponseTypes {
// The shape of the data coming back from the server will
// vary quite a bit based on the exact protocol being used,
// age of the service, etc. Before we parse the data, we need
// to understand what we're expecting. Because types are handled
// at comptime, we are restricted in how we handle them. They must
// be constants, so first we'll set up an unreasonable "NullType"
// we can use in our conditionals below
const NullType: type = u0;
// Next, we'll provide a "SResponse", or Server Response, for a
// "normal" return that modern AWS services provide, that includes
// meta information and a result inside it. This could be the
// response as described in our models, or it could be a wrapped
// response that's only applicable to aws_query smithy protocol
// services
const SResponse = if (Self.service_meta.aws_protocol != .query)
action.Response
else
ServerResponse(action);
// Now, we want to also establish a "SRawResponse", or a raw
// response. Some older services (like CloudFront) respect
// that we desire application/json data even though they're
// considered "rest_xml" protocol. However, they don't wrap
// anything, so we actually want to parse the only field in
// the response structure. In this case we have to manually
// create the type, parse, then set the field. For example:
//
// Response: type = struct {
// key_group_list: ?struct {...
//
// Normal responses would start parsing on the Response type,
// but raw responses need to create an instance of the response
// type, and parse "key_group_list" directly before attaching.
//
// Because we cannot change types at runtime, we need to create
// both a SResponse and SRawResponse type in anticipation of either
// scenario, then parse as appropriate later
const SRawResponse = if (Self.service_meta.aws_protocol != .query and
std.meta.fields(action.Response).len == 1)
std.meta.fields(action.Response)[0].field_type
else
NullType;
return .{
.NormalResponse = SResponse,
.RawResponse = SRawResponse,
.isRawPossible = SRawResponse != NullType,
};
}
fn ParsedJsonData(comptime T: type) type {
return struct {
raw_response_parsed: bool,
parsed_response_ptr: *T,
allocator: std.mem.Allocator,
const MySelf = @This();
pub fn deinit(self: MySelf) void {
// This feels like it should result in a use after free, but it
// seems to be working?
if (self.raw_response_parsed)
self.allocator.destroy(self.parsed_response_ptr);
}
};
}
fn parseJsonData(comptime response_types: ServerResponseTypes, data: []const u8, options: Options, parser_options: json.ParseOptions) !ParsedJsonData(response_types.NormalResponse) {
// Now it's time to start looking at the actual data. Job 1 will
// be to figure out if this is a raw response or wrapped
// Extract the first json key
const key = firstJsonKey(data);
const found_normal_json_response = std.mem.eql(u8, key, action.action_name ++ "Response") or
std.mem.eql(u8, key, action.action_name ++ "Result");
var raw_response_parsed = false;
var stream = json.TokenStream.init(data);
const parsed_response_ptr = blk: {
if (!response_types.isRawPossible or found_normal_json_response)
break :blk &(json.parse(response_types.NormalResponse, &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.
\\
\\Model Type: {s}
\\
\\Response from server:
\\
\\{s}
\\
, .{ action.Response, data });
return e;
});
log.debug("Appears server has provided a raw response", .{});
raw_response_parsed = true;
const ptr = try options.client.allocator.create(response_types.NormalResponse);
@field(ptr.*, std.meta.fields(action.Response)[0].name) =
json.parse(response_types.RawResponse, &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.
\\
\\Model Type: {s}
\\
\\Response from server:
\\
\\{s}
\\
, .{ action.Response, data });
return e;
};
break :blk ptr;
};
return ParsedJsonData(response_types.NormalResponse){
.raw_response_parsed = raw_response_parsed,
.parsed_response_ptr = parsed_response_ptr,
.allocator = options.client.allocator,
};
}
};
}
fn firstJsonKey(data: []const u8) []const u8 {
const start = std.mem.indexOf(u8, data, "\"") orelse 0; // Should never be 0
if (start == 0) log.warn("Response body missing json key?!", .{});
var end = std.mem.indexOf(u8, data[start + 1 ..], "\"") orelse 0;
if (end == 0) log.warn("Response body only has one double quote?!", .{});
end = end + start + 1;
const key = data[start + 1 .. end];
log.debug("First json key: {s}", .{key});
return key;
}
fn isJsonResponse(headers: []awshttp.Header) !bool {
// EC2 ignores our accept type, but technically query protocol only
// returns XML as well. So, we'll ignore the protocol here and just