move executor config to external file

proxy.ini

@@ -0,0 +1,8 @@
+# This is a simple "path prefix" = dynamic library path mapping
+# no reordering will be done, so you must do things most -> least specific
+# because all paths start with a '/', we may be able to later add the ability
+# for libraries to self-select whether they can handle a request, which opens
+# up additional possibilities
+
+/c = zig-out/lib/libfaas-proxy-sample-lib-in-c.so
+/ = zig-out/lib/libfaas-proxy-sample-lib.so

src/config.zig

@@ -4,18 +4,18 @@ const std = @import("std");
 allocator: std.mem.Allocator,
 
 pub const ParsedConfig = struct {
-    key_value_map: *std.StringArrayHashMap([]u8),
-    value_key_map: *std.StringArrayHashMap(*std.ArrayList([]u8)),
+    key_value_map: *std.StringArrayHashMap([:0]u8),
+    value_key_map: *std.StringArrayHashMap(*std.ArrayList([:0]u8)),
 
     config_allocator: std.mem.Allocator,
     const SelfConfig = @This();
 
-    var by_keys: std.StringArrayHashMap([]u8) = undefined;
-    var by_values: std.StringArrayHashMap(*std.ArrayList([]u8)) = undefined;
+    var by_keys: std.StringArrayHashMap([:0]u8) = undefined;
+    var by_values: std.StringArrayHashMap(*std.ArrayList([:0]u8)) = undefined;
 
     pub fn init(config_allocator: std.mem.Allocator) SelfConfig {
-        by_keys = std.StringArrayHashMap([]u8).init(config_allocator);
-        by_values = std.StringArrayHashMap(*std.ArrayList([]u8)).init(config_allocator);
+        by_keys = std.StringArrayHashMap([:0]u8).init(config_allocator);
+        by_values = std.StringArrayHashMap(*std.ArrayList([:0]u8)).init(config_allocator);
         return SelfConfig{
             .config_allocator = config_allocator,
             .key_value_map = &by_keys,
@@ -25,7 +25,8 @@ pub const ParsedConfig = struct {
 
     pub fn deinit(self: *SelfConfig) void {
         for (self.key_value_map.keys(), self.key_value_map.values()) |k, v| {
-            self.config_allocator.free(k); // this is also the key in value_key_map
+            // StringArrayHashMap assumes []const u8, but what we've allocated is null terminated
+            self.config_allocator.free(@ptrCast([:0]const u8, k)); // this is also the key in value_key_map
             self.config_allocator.free(v);
         }
 
@@ -70,12 +71,12 @@ pub fn parse(self: Self, reader: anytype) !ParsedConfig {
         // keys should be putNoClobber, but values can be put.
         // Because we have to dup the memory here though, we want to
         // manage duplicate values seperately
-        var dup_key = try self.allocator.dupe(u8, key);
-        var dup_value = try self.allocator.dupe(u8, value);
+        var dup_key = try self.allocator.dupeZ(u8, key);
+        var dup_value = try self.allocator.dupeZ(u8, value);
         try rc.key_value_map.putNoClobber(dup_key, dup_value);
         if (!rc.value_key_map.contains(value)) {
-            var keys = try self.allocator.create(std.ArrayList([]u8));
-            keys.* = std.ArrayList([]u8).init(self.allocator);
+            var keys = try self.allocator.create(std.ArrayList([:0]u8));
+            keys.* = std.ArrayList([:0]u8).init(self.allocator);
             try rc.value_key_map.put(dup_value, keys);
         }
         try rc.value_key_map.get(value).?.append(dup_key);

src/main.zig

@@ -16,6 +16,7 @@ const FullReturn = struct {
 
 const Executor = struct {
     // configuration
+    target_prefix: []const u8,
     path: [:0]const u8,
 
     // fields used at runtime to do real work
@@ -30,13 +31,6 @@ const Executor = struct {
     in_request_lock: bool = false,
 };
 
-// TODO: This should be in a file that maybe gets reloaded with SIGHUP
-// rather than a file watch. Touching this config is pretty dangerous
-var executors = [_]Executor{
-    .{ .path = "zig-out/lib/libfaas-proxy-sample-lib.so" },
-    .{ .path = "zig-out/lib/libfaas-proxy-sample-lib2.so" },
-};
-
 var watcher = Watch.init(executorChanged);
 var watcher_thread: ?std.Thread = null;
 var timer: ?std.time.Timer = null; // timer used by processRequest
@@ -52,9 +46,11 @@ pub const std_options = struct {
 const SERVE_FN_NAME = "handle_request";
 const PORT = 8069;
 
+var executors: []Executor = undefined;
+
 fn serve(allocator: *std.mem.Allocator, response: *std.http.Server.Response) !*FullReturn {
     // if (some path routing thing) {
-    const executor = try getExecutor(0);
+    const executor = try getExecutor(response.request.target);
     if (executor.zigInitFn) |f|
         f(allocator);
 
@@ -104,8 +100,16 @@ fn serve(allocator: *std.mem.Allocator, response: *std.http.Server.Response) !*F
     rc.response = slice;
     return rc;
 }
-fn getExecutor(key: usize) !*Executor {
-    var executor = &executors[key];
+fn getExecutor(requested_path: []const u8) !*Executor {
+    var executor = blk: {
+        for (executors) |*exec| {
+            if (std.mem.startsWith(u8, requested_path, exec.target_prefix)) {
+                break :blk exec;
+            }
+        }
+        log.err("Could not find executor for target path '{s}'", .{requested_path});
+        return error.NoApplicableExecutor;
+    };
     if (executor.serveFn != null) return executor;
 
     executor.library = blk: {
@@ -146,7 +150,7 @@ fn loadOptionalSymbols(executor: *Executor) void {
 fn executorChanged(watch: usize) void {
     // NOTE: This will be called off the main thread
     log.debug("executor with watch {d} changed", .{watch});
-    for (&executors) |*executor| {
+    for (executors) |*executor| {
         if (executor.watch) |w| {
             if (w == watch) {
                 if (executor.library) |l| {
@@ -231,9 +235,13 @@ pub fn main() !void {
     var bw = std.io.bufferedWriter(stdout_file);
     const stdout = bw.writer();
 
+    var allocator = std.heap.raw_c_allocator; // raw allocator recommended for use in arenas
+    executors = try loadConfig(allocator);
+    defer allocator.free(executors);
+    defer parsed_config.deinit();
+
     watcher_thread = try std.Thread.spawn(.{}, Watch.startWatch, .{&watcher});
 
-    var allocator = std.heap.raw_c_allocator; // raw allocator recommended for use in arenas
     var server = std.http.Server.init(allocator, .{ .reuse_address = true });
     defer server.deinit();
 
@@ -270,6 +278,23 @@ pub fn main() !void {
         try bw.flush();
     }
 }
+var parsed_config: config.ParsedConfig = undefined;
+fn loadConfig(allocator: std.mem.Allocator) ![]Executor {
+    log.info("loading config", .{});
+    // We will not watch this file - let it reload on SIGHUP
+    var config_file = try std.fs.cwd().openFile("proxy.ini", .{});
+    defer config_file.close();
+    parsed_config = try config.init(allocator).parse(config_file.reader());
+    var al = try std.ArrayList(Executor).initCapacity(allocator, parsed_config.key_value_map.keys().len);
+    defer al.deinit();
+    for (parsed_config.key_value_map.keys(), parsed_config.key_value_map.values()) |k, v| {
+        al.appendAssumeCapacity(.{
+            .target_prefix = k,
+            .path = v,
+        });
+    }
+    return al.toOwnedSlice();
+}
 
 fn processRequest(allocator: *std.mem.Allocator, server: *std.http.Server, writer: anytype) !void {
     const max_header_size = 8192;
@@ -371,6 +396,9 @@ fn writeToTestBuffers(response: []const u8, res: *std.http.Server.Response) void
 }
 fn testRequest(request_bytes: []const u8) !void {
     const allocator = std.testing.allocator;
+    executors = try loadConfig(allocator);
+    defer allocator.free(executors);
+    defer parsed_config.deinit();
     var arena = std.heap.ArenaAllocator.init(allocator);
     defer arena.deinit();