rate limiter refactor

src/net/RateLimiter.zig

@@ -0,0 +1,93 @@
+//! Token-bucket rate limiter.
+//!
+//! Enforces a maximum number of requests per time window using the
+//! token bucket algorithm. Tokens refill continuously; each request
+//! consumes one token. When the bucket is empty, callers can either
+//! poll with `tryAcquire` or block with `acquire`.
+
+const std = @import("std");
+
+/// Maximum tokens (requests) in the bucket
+max_tokens: u32,
+/// Current available tokens
+tokens: f64,
+/// Tokens added per nanosecond
+refill_rate_per_ns: f64,
+/// Last time tokens were refilled
+last_refill: i128,
+
+const RateLimiter = @This();
+
+/// Create a rate limiter.
+/// `max_per_window` is the max requests allowed in `window_ns` nanoseconds.
+pub fn init(max_per_window: u32, window_ns: u64) RateLimiter {
+    return .{
+        .max_tokens = max_per_window,
+        .tokens = @floatFromInt(max_per_window),
+        .refill_rate_per_ns = @as(f64, @floatFromInt(max_per_window)) / @as(f64, @floatFromInt(window_ns)),
+        .last_refill = std.time.nanoTimestamp(),
+    };
+}
+
+/// Convenience: N requests per minute
+pub fn perMinute(n: u32) RateLimiter {
+    return init(n, std.time.ns_per_min);
+}
+
+/// Convenience: N requests per day
+pub fn perDay(n: u32) RateLimiter {
+    return init(n, std.time.ns_per_day);
+}
+
+/// Try to acquire a token. Returns true if granted, false if rate-limited.
+/// Caller should sleep and retry if false.
+pub fn tryAcquire(self: *RateLimiter) bool {
+    self.refill();
+    if (self.tokens >= 1.0) {
+        self.tokens -= 1.0;
+        return true;
+    }
+    return false;
+}
+
+/// Acquire a token, blocking (sleeping) until one is available.
+pub fn acquire(self: *RateLimiter) void {
+    while (!self.tryAcquire()) {
+        // Sleep for the time needed to generate 1 token
+        const wait_ns: u64 = @intFromFloat(1.0 / self.refill_rate_per_ns);
+        std.Thread.sleep(wait_ns);
+    }
+}
+
+/// Returns estimated wait time in nanoseconds until a token is available.
+/// Returns 0 if a token is available now.
+pub fn estimateWaitNs(self: *RateLimiter) u64 {
+    self.refill();
+    if (self.tokens >= 1.0) return 0;
+    const deficit = 1.0 - self.tokens;
+    return @intFromFloat(deficit / self.refill_rate_per_ns);
+}
+
+fn refill(self: *RateLimiter) void {
+    const now = std.time.nanoTimestamp();
+    const elapsed = now - self.last_refill;
+    if (elapsed <= 0) return;
+
+    const new_tokens = @as(f64, @floatFromInt(elapsed)) * self.refill_rate_per_ns;
+    self.tokens = @min(self.tokens + new_tokens, @as(f64, @floatFromInt(self.max_tokens)));
+    self.last_refill = now;
+}
+
+test "rate limiter basic" {
+    var rl = RateLimiter.perMinute(60);
+    // Should have full bucket initially
+    try std.testing.expect(rl.tryAcquire());
+}
+
+test "rate limiter exhaustion" {
+    var rl = RateLimiter.init(2, std.time.ns_per_s);
+    try std.testing.expect(rl.tryAcquire());
+    try std.testing.expect(rl.tryAcquire());
+    // Bucket should be empty now
+    try std.testing.expect(!rl.tryAcquire());
+}

src/net/rate_limiter.zig

@@ -1,87 +0,0 @@
-const std = @import("std");
-
-/// Token-bucket rate limiter. Enforces a maximum number of requests per time window.
-pub const RateLimiter = struct {
-    /// Maximum tokens (requests) in the bucket
-    max_tokens: u32,
-    /// Current available tokens
-    tokens: f64,
-    /// Tokens added per nanosecond
-    refill_rate_per_ns: f64,
-    /// Last time tokens were refilled
-    last_refill: i128,
-
-    /// Create a rate limiter.
-    /// `max_per_window` is the max requests allowed in `window_ns` nanoseconds.
-    pub fn init(max_per_window: u32, window_ns: u64) RateLimiter {
-        return .{
-            .max_tokens = max_per_window,
-            .tokens = @floatFromInt(max_per_window),
-            .refill_rate_per_ns = @as(f64, @floatFromInt(max_per_window)) / @as(f64, @floatFromInt(window_ns)),
-            .last_refill = std.time.nanoTimestamp(),
-        };
-    }
-
-    /// Convenience: N requests per minute
-    pub fn perMinute(n: u32) RateLimiter {
-        return init(n, 60 * std.time.ns_per_s);
-    }
-
-    /// Convenience: N requests per day
-    pub fn perDay(n: u32) RateLimiter {
-        return init(n, 24 * 3600 * std.time.ns_per_s);
-    }
-
-    /// Try to acquire a token. Returns true if granted, false if rate-limited.
-    /// Caller should sleep and retry if false.
-    pub fn tryAcquire(self: *RateLimiter) bool {
-        self.refill();
-        if (self.tokens >= 1.0) {
-            self.tokens -= 1.0;
-            return true;
-        }
-        return false;
-    }
-
-    /// Acquire a token, blocking (sleeping) until one is available.
-    pub fn acquire(self: *RateLimiter) void {
-        while (!self.tryAcquire()) {
-            // Sleep for the time needed to generate 1 token
-            const wait_ns: u64 = @intFromFloat(1.0 / self.refill_rate_per_ns);
-            std.Thread.sleep(wait_ns);
-        }
-    }
-
-    /// Returns estimated wait time in nanoseconds until a token is available.
-    /// Returns 0 if a token is available now.
-    pub fn estimateWaitNs(self: *RateLimiter) u64 {
-        self.refill();
-        if (self.tokens >= 1.0) return 0;
-        const deficit = 1.0 - self.tokens;
-        return @intFromFloat(deficit / self.refill_rate_per_ns);
-    }
-
-    fn refill(self: *RateLimiter) void {
-        const now = std.time.nanoTimestamp();
-        const elapsed = now - self.last_refill;
-        if (elapsed <= 0) return;
-
-        const new_tokens = @as(f64, @floatFromInt(elapsed)) * self.refill_rate_per_ns;
-        self.tokens = @min(self.tokens + new_tokens, @as(f64, @floatFromInt(self.max_tokens)));
-        self.last_refill = now;
-    }
-};
-
-test "rate limiter basic" {
-    var rl = RateLimiter.perMinute(60);
-    // Should have full bucket initially
-    try std.testing.expect(rl.tryAcquire());
-}
-
-test "rate limiter exhaustion" {
-    var rl = RateLimiter.init(2, std.time.ns_per_s);
-    try std.testing.expect(rl.tryAcquire());
-    try std.testing.expect(rl.tryAcquire());
-    // Bucket should be empty now
-    try std.testing.expect(!rl.tryAcquire());
-}

src/providers/alphavantage.zig

@@ -8,7 +8,7 @@
 
 const std = @import("std");
 const http = @import("../net/http.zig");
-const RateLimiter = @import("../net/rate_limiter.zig").RateLimiter;
+const RateLimiter = @import("../net/RateLimiter.zig");
 const Date = @import("../models/date.zig").Date;
 const EtfProfile = @import("../models/etf_profile.zig").EtfProfile;
 const Holding = @import("../models/etf_profile.zig").Holding;

src/providers/cboe.zig

@@ -6,7 +6,7 @@
 
 const std = @import("std");
 const http = @import("../net/http.zig");
-const RateLimiter = @import("../net/rate_limiter.zig").RateLimiter;
+const RateLimiter = @import("../net/RateLimiter.zig");
 const Date = @import("../models/date.zig").Date;
 const OptionContract = @import("../models/option.zig").OptionContract;
 const OptionsChain = @import("../models/option.zig").OptionsChain;

src/providers/finnhub.zig

@@ -11,7 +11,7 @@
 
 const std = @import("std");
 const http = @import("../net/http.zig");
-const RateLimiter = @import("../net/rate_limiter.zig").RateLimiter;
+const RateLimiter = @import("../net/RateLimiter.zig");
 const Date = @import("../models/date.zig").Date;
 const OptionContract = @import("../models/option.zig").OptionContract;
 const OptionsChain = @import("../models/option.zig").OptionsChain;

src/providers/polygon.zig

@@ -7,7 +7,7 @@
 
 const std = @import("std");
 const http = @import("../net/http.zig");
-const RateLimiter = @import("../net/rate_limiter.zig").RateLimiter;
+const RateLimiter = @import("../net/RateLimiter.zig");
 const Date = @import("../models/date.zig").Date;
 const Candle = @import("../models/candle.zig").Candle;
 const Dividend = @import("../models/dividend.zig").Dividend;

src/providers/twelvedata.zig

@@ -9,7 +9,7 @@
 
 const std = @import("std");
 const http = @import("../net/http.zig");
-const RateLimiter = @import("../net/rate_limiter.zig").RateLimiter;
+const RateLimiter = @import("../net/RateLimiter.zig");
 const Date = @import("../models/date.zig").Date;
 const Candle = @import("../models/candle.zig").Candle;
 const provider = @import("provider.zig");