working sample

src/main.zig

@@ -1,15 +1,67 @@
 const std = @import("std");
 const requestz = @import("requestz");
 
+// zig build -Drelease-safe && strip zig-out/bin/bootstrap && zip -j9 function.zip zig-out/bin/bootstrap && aws lambda update-function-code --function-name zig-test --zip-file fileb://function.zip
 pub fn main() anyerror!void {
+    try run(handler);
+}
+
+fn handler(allocator: *std.mem.Allocator, event_data: []const u8) ![]const u8 {
+    _ = allocator;
+    return event_data;
+}
+
+pub fn run(event_handler: fn (*std.mem.Allocator, []const u8) anyerror![]const u8) !void { // TODO: remove inferred error set?
+    const prefix = "http://";
+    const postfix = "/2018-06-01/runtime/invocation";
+    const lambda_runtime_uri = std.os.getenv("AWS_LAMBDA_RUNTIME_API");
+
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer _ = gpa.deinit();
     const allocator = &gpa.allocator;
 
-    var client = try requestz.Client.init(allocator);
-    defer client.deinit();
+    const url = try std.fmt.allocPrint(allocator, "{s}{s}{s}/next", .{ prefix, lambda_runtime_uri, postfix });
+    defer allocator.free(url);
 
-    var response = try client.get("http://captive.lerch.org/", .{});
-    std.log.info("{s}", .{response.body});
-    defer response.deinit();
+    std.log.info("Event Url: {s}", .{url});
+
+    while (true) {
+        var req_alloc = std.heap.ArenaAllocator.init(allocator);
+        defer req_alloc.deinit();
+        const req_allocator = &req_alloc.allocator;
+        var client = try requestz.Client.init(req_allocator);
+        // defer client.deinit();
+        var response = client.get(url, .{}) catch |err| {
+            // TODO: report error
+            std.log.err("Get fail: {}", .{err});
+            continue;
+        };
+        defer response.deinit();
+
+        var request_id: ?[]const u8 = null;
+        for (response.headers.items()) |h| {
+            if (std.mem.indexOf(u8, h.name.value, "Lambda-Runtime-Aws-Request-Id")) |_|
+                request_id = h.value;
+        }
+        if (request_id == null) {
+            // TODO: report error
+            std.log.err("Could not find request id: skipping request", .{});
+            continue;
+        }
+        const req_id = request_id.?;
+
+        const event_response = event_handler(req_allocator, response.body) catch |err| {
+            // TODO: report error
+            std.log.err("Error posting response for request id {s}: {}", .{ req_id, err });
+            continue;
+        };
+        const response_url = try std.fmt.allocPrint(req_allocator, "{s}{s}{s}/{s}/response", .{ prefix, lambda_runtime_uri, postfix, req_id });
+        // defer req_allocator.free(response_url);
+        var resp_resp = client.post(response_url, .{ .content = event_response }) catch |err| {
+            // TODO: report error
+            std.log.err("Error posting response for request id {s}: {}", .{ req_id, err });
+            continue;
+        };
+        defer resp_resp.deinit();
+    }
 }