nautilus_common/generators/
position_id.rs

1// -------------------------------------------------------------------------------------------------
2//  Copyright (C) 2015-2026 Nautech Systems Pty Ltd. All rights reserved.
3//  https://nautechsystems.io
4//
5//  Licensed under the GNU Lesser General Public License Version 3.0 (the "License");
6//  You may not use this file except in compliance with the License.
7//  You may obtain a copy of the License at https://www.gnu.org/licenses/lgpl-3.0.en.html
8//
9//  Unless required by applicable law or agreed to in writing, software
10//  distributed under the License is distributed on an "AS IS" BASIS,
11//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12//  See the License for the specific language governing permissions and
13//  limitations under the License.
14// -------------------------------------------------------------------------------------------------
15
16use std::{
17    cell::RefCell,
18    collections::HashMap,
19    fmt::{Debug, Write},
20    rc::Rc,
21};
22
23use chrono::{DateTime, Datelike, Timelike};
24use itoa::Buffer;
25use nautilus_model::identifiers::{PositionId, StrategyId, TraderId};
26
27use crate::clock::Clock;
28
29const DATETIME_TAG_LEN: usize = 15; // "YYYYMMDD-HHMMSS"
30// Reserve for strategy_tag + "-" + decimal count + optional "F" past the cached fixed prefix
31const STRATEGY_AND_COUNT_RESERVE: usize = 32;
32
33#[repr(C)]
34pub struct PositionIdGenerator {
35    clock: Rc<RefCell<dyn Clock>>,
36    trader_id: TraderId,
37    counts: HashMap<StrategyId, usize>,
38    trader_tag: String,
39    buf: String,
40    fixed_prefix_len: usize,
41    epoch_second: u64,
42    count_buf: Buffer,
43}
44
45impl Debug for PositionIdGenerator {
46    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
47        f.debug_struct(stringify!(PositionIdGenerator))
48            .field("trader_id", &self.trader_id)
49            .field("counts", &self.counts)
50            .field("trader_tag", &self.trader_tag)
51            .field("buf", &self.buf)
52            .field("fixed_prefix_len", &self.fixed_prefix_len)
53            .field("epoch_second", &self.epoch_second)
54            .finish_non_exhaustive()
55    }
56}
57
58impl PositionIdGenerator {
59    /// Creates a new [`PositionIdGenerator`] instance.
60    #[must_use]
61    pub fn new(trader_id: TraderId, clock: Rc<RefCell<dyn Clock>>) -> Self {
62        let trader_tag = trader_id.get_tag().to_string();
63        let buf = String::with_capacity(
64            "P-".len()
65                + DATETIME_TAG_LEN
66                + "-".len()
67                + trader_tag.len()
68                + "-".len()
69                + STRATEGY_AND_COUNT_RESERVE,
70        );
71
72        Self {
73            clock,
74            trader_id,
75            counts: HashMap::new(),
76            trader_tag,
77            buf,
78            fixed_prefix_len: 0,
79            epoch_second: u64::MAX,
80            count_buf: Buffer::new(),
81        }
82    }
83
84    pub fn set_count(&mut self, count: usize, strategy_id: StrategyId) {
85        self.counts.insert(strategy_id, count);
86    }
87
88    pub fn reset(&mut self) {
89        self.counts.clear();
90    }
91
92    #[must_use]
93    pub fn count(&self, strategy_id: StrategyId) -> usize {
94        *self.counts.get(&strategy_id).unwrap_or(&0)
95    }
96
97    pub fn generate(&mut self, strategy_id: StrategyId, flipped: bool) -> PositionId {
98        let next_count = self.count(strategy_id) + 1;
99        self.set_count(next_count, strategy_id);
100
101        let timestamp_ms = self.clock.borrow().timestamp_ms();
102        self.refresh_fixed_prefix(timestamp_ms);
103
104        self.buf.truncate(self.fixed_prefix_len);
105        self.buf.push_str(strategy_id.get_tag());
106        self.buf.push('-');
107        self.buf.push_str(self.count_buf.format(next_count));
108        if flipped {
109            self.buf.push('F');
110        }
111
112        PositionId::from(self.buf.as_str())
113    }
114
115    #[inline]
116    fn refresh_fixed_prefix(&mut self, timestamp_ms: u64) {
117        let epoch_second = timestamp_ms / 1_000;
118        if epoch_second == self.epoch_second {
119            return;
120        }
121
122        write_fixed_prefix(&mut self.buf, &self.trader_tag, epoch_second);
123        self.fixed_prefix_len = self.buf.len();
124        self.epoch_second = epoch_second;
125    }
126}
127
128fn write_fixed_prefix(buf: &mut String, trader_tag: &str, epoch_second: u64) {
129    let now_utc = DateTime::from_timestamp_millis((epoch_second * 1_000) as i64)
130        .expect("Milliseconds timestamp should be within valid range");
131
132    buf.clear();
133
134    write!(
135        buf,
136        "P-{:04}{:02}{:02}-{:02}{:02}{:02}-{trader_tag}-",
137        now_utc.year(),
138        now_utc.month(),
139        now_utc.day(),
140        now_utc.hour(),
141        now_utc.minute(),
142        now_utc.second(),
143    )
144    .expect("writing to String should not fail");
145}
146
147#[cfg(test)]
148mod tests {
149    use std::{cell::RefCell, rc::Rc};
150
151    use nautilus_core::UnixNanos;
152    use nautilus_model::{
153        identifiers::{PositionId, StrategyId, TraderId},
154        stubs::TestDefault,
155    };
156    use rstest::rstest;
157
158    use crate::{clock::TestClock, generators::position_id::PositionIdGenerator};
159
160    fn get_position_id_generator() -> PositionIdGenerator {
161        PositionIdGenerator::new(
162            TraderId::test_default(),
163            Rc::new(RefCell::new(TestClock::new())),
164        )
165    }
166
167    #[rstest]
168    fn test_generate_position_id_one_strategy() {
169        let mut generator = get_position_id_generator();
170        let result1 = generator.generate(StrategyId::from("S-001"), false);
171        let result2 = generator.generate(StrategyId::from("S-001"), false);
172
173        assert_eq!(result1, PositionId::from("P-19700101-000000-001-001-1"));
174        assert_eq!(result2, PositionId::from("P-19700101-000000-001-001-2"));
175    }
176
177    #[rstest]
178    fn test_generate_position_id_multiple_strategies() {
179        let mut generator = get_position_id_generator();
180        let result1 = generator.generate(StrategyId::from("S-001"), false);
181        let result2 = generator.generate(StrategyId::from("S-002"), false);
182        let result3 = generator.generate(StrategyId::from("S-002"), false);
183
184        assert_eq!(result1, PositionId::from("P-19700101-000000-001-001-1"));
185        assert_eq!(result2, PositionId::from("P-19700101-000000-001-002-1"));
186        assert_eq!(result3, PositionId::from("P-19700101-000000-001-002-2"));
187    }
188
189    #[rstest]
190    fn test_generate_position_id_with_flipped_appends_correctly() {
191        let mut generator = get_position_id_generator();
192        let result1 = generator.generate(StrategyId::from("S-001"), false);
193        let result2 = generator.generate(StrategyId::from("S-002"), true);
194        let result3 = generator.generate(StrategyId::from("S-001"), true);
195
196        assert_eq!(result1, PositionId::from("P-19700101-000000-001-001-1"));
197        assert_eq!(result2, PositionId::from("P-19700101-000000-001-002-1F"));
198        assert_eq!(result3, PositionId::from("P-19700101-000000-001-001-2F"));
199    }
200
201    #[rstest]
202    fn test_generate_persists_fixed_prefix_in_buffer_within_same_second() {
203        let mut generator = get_position_id_generator();
204
205        let result1 = generator.generate(StrategyId::from("S-001"), false);
206        let fixed_prefix = "P-19700101-000000-001-";
207        let capacity_after_first = generator.buf.capacity();
208
209        assert_eq!(result1, PositionId::from("P-19700101-000000-001-001-1"));
210        assert_eq!(generator.fixed_prefix_len, fixed_prefix.len());
211        assert_eq!(&generator.buf[..generator.fixed_prefix_len], fixed_prefix);
212
213        let result2 = generator.generate(StrategyId::from("S-001"), false);
214
215        assert_eq!(result2, PositionId::from("P-19700101-000000-001-001-2"));
216        assert_eq!(generator.fixed_prefix_len, fixed_prefix.len());
217        assert_eq!(&generator.buf[..generator.fixed_prefix_len], fixed_prefix);
218        assert_eq!(generator.buf.capacity(), capacity_after_first);
219    }
220
221    #[rstest]
222    fn test_generate_capacity_stable_across_strategies_same_second() {
223        let mut generator = get_position_id_generator();
224
225        // Prime the buffer; subsequent calls must not reallocate while strategies fit
226        // within STRATEGY_AND_COUNT_RESERVE.
227        generator.generate(StrategyId::from("S-001"), false);
228        let capacity_after_warmup = generator.buf.capacity();
229
230        for tag in ["S-002", "S-003", "STRATEGY-LONGER-001"] {
231            generator.generate(StrategyId::from(tag), false);
232        }
233
234        assert_eq!(generator.buf.capacity(), capacity_after_warmup);
235    }
236
237    #[rstest]
238    fn test_generate_refreshes_persistent_fixed_prefix_when_second_changes() {
239        let clock = Rc::new(RefCell::new(TestClock::new()));
240        let mut generator = PositionIdGenerator::new(TraderId::test_default(), clock.clone());
241
242        let result1 = generator.generate(StrategyId::from("S-001"), false);
243        clock.borrow_mut().set_time(UnixNanos::from(1_000_000_000));
244        let result2 = generator.generate(StrategyId::from("S-001"), false);
245
246        assert_eq!(result1, PositionId::from("P-19700101-000000-001-001-1"));
247        assert_eq!(result2, PositionId::from("P-19700101-000001-001-001-2"));
248        assert_eq!(generator.epoch_second, 1);
249        assert_eq!(
250            &generator.buf[..generator.fixed_prefix_len],
251            "P-19700101-000001-001-"
252        );
253    }
254
255    #[rstest]
256    fn test_get_count_when_strategy_id_has_not_been_used() {
257        let generator = get_position_id_generator();
258        let result = generator.count(StrategyId::from("S-001"));
259
260        assert_eq!(result, 0);
261    }
262
263    #[rstest]
264    fn set_count_with_valid_strategy() {
265        let mut generator = get_position_id_generator();
266        generator.set_count(7, StrategyId::from("S-001"));
267        let result = generator.count(StrategyId::from("S-001"));
268
269        assert_eq!(result, 7);
270    }
271
272    #[rstest]
273    fn test_reset() {
274        let mut generator = get_position_id_generator();
275        generator.generate(StrategyId::from("S-001"), false);
276        generator.generate(StrategyId::from("S-001"), false);
277        generator.reset();
278        let result = generator.generate(StrategyId::from("S-001"), false);
279
280        assert_eq!(result, PositionId::from("P-19700101-000000-001-001-1"));
281    }
282}
nautilus_common/generators/position_id.rs

nautilus_common/generators/
position_id.rs
