krafka 0.7.0

A pure Rust, async-native Apache Kafka client
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454

use bytes::{Buf, BufMut};

use super::{VersionedDecode, VersionedEncode, non_nullable_string};
use crate::error::{ErrorCode, KrafkaError, Result};
use crate::protocol::api::ApiKey;
use crate::protocol::primitives::{Decode, KafkaString, TaggedFields, TryEncode};
use crate::protocol::{check_compact_array_len, check_decode_array_len};

// ============================================================================
// ListGroups API (Key 16)
// ============================================================================

/// ListGroups request.
#[derive(Debug, Clone)]
pub struct ListGroupsRequest {
    /// State filter (v4+, KIP-518). Empty means all states.
    pub states_filter: Vec<String>,
    /// Type filter (v5+, KIP-848). Empty means all types.
    pub types_filter: Vec<String>,
}

impl ListGroupsRequest {
    /// Get the API key.
    pub fn api_key() -> ApiKey {
        ApiKey::ListGroups
    }

    /// Encode for version 1–2 (empty body).
    pub fn encode_v1(&self, buf: &mut impl BufMut) -> Result<()> {
        let _ = buf;
        Ok(())
    }

    /// Encode for version 3 (flexible, empty body + tagged fields).
    pub fn encode_v3(&self, buf: &mut impl BufMut) -> Result<()> {
        TaggedFields::default().try_encode(buf)?;
        Ok(())
    }

    /// Encode for version 4 (flexible, adds states_filter).
    pub fn encode_v4(&self, buf: &mut impl BufMut) -> Result<()> {
        let len = u32::try_from(self.states_filter.len().saturating_add(1))
            .map_err(|_| KrafkaError::protocol("states_filter array too large"))?;
        crate::util::varint::encode_unsigned_varint(len, buf);
        for state in &self.states_filter {
            KafkaString::new(state).try_encode_compact(buf)?;
        }
        TaggedFields::default().try_encode(buf)?;
        Ok(())
    }

    /// Encode for version 5 (flexible, adds types_filter).
    pub fn encode_v5(&self, buf: &mut impl BufMut) -> Result<()> {
        let states_len = u32::try_from(self.states_filter.len().saturating_add(1))
            .map_err(|_| KrafkaError::protocol("states_filter array too large"))?;
        crate::util::varint::encode_unsigned_varint(states_len, buf);
        for state in &self.states_filter {
            KafkaString::new(state).try_encode_compact(buf)?;
        }
        let types_len = u32::try_from(self.types_filter.len().saturating_add(1))
            .map_err(|_| KrafkaError::protocol("types_filter array too large"))?;
        crate::util::varint::encode_unsigned_varint(types_len, buf);
        for t in &self.types_filter {
            KafkaString::new(t).try_encode_compact(buf)?;
        }
        TaggedFields::default().try_encode(buf)?;
        Ok(())
    }
}

/// A listed group.
#[derive(Debug, Clone)]
pub struct ListedGroup {
    /// Group ID.
    pub group_id: String,
    /// Protocol type.
    pub protocol_type: String,
    /// Group state (v4+, KIP-518).
    pub group_state: Option<String>,
    /// Group type (v5+, KIP-848).
    pub group_type: Option<String>,
}

/// ListGroups response.
#[derive(Debug, Clone)]
pub struct ListGroupsResponse {
    /// Throttle time (v1+).
    pub throttle_time_ms: i32,
    /// Error code.
    pub error_code: ErrorCode,
    /// Listed groups.
    pub groups: Vec<ListedGroup>,
}

impl ListGroupsResponse {
    /// Decode from version 1–2 (non-flexible).
    pub fn decode_v1(buf: &mut impl Buf) -> Result<Self> {
        let throttle_time_ms = i32::decode(buf)?;
        let error_code = ErrorCode::from_i16(i16::decode(buf)?);
        let group_count = check_decode_array_len(i32::decode(buf)?)?;
        let mut groups = Vec::with_capacity(group_count);
        for _ in 0..group_count {
            let group_id = non_nullable_string("group_id", KafkaString::decode(buf)?.0)?;
            let protocol_type = non_nullable_string("protocol_type", KafkaString::decode(buf)?.0)?;
            groups.push(ListedGroup {
                group_id,
                protocol_type,
                group_state: None,
                group_type: None,
            });
        }
        Ok(Self {
            throttle_time_ms,
            error_code,
            groups,
        })
    }

    /// Decode from version 3 (flexible, no new fields).
    pub fn decode_v3(buf: &mut impl Buf) -> Result<Self> {
        let throttle_time_ms = i32::decode(buf)?;
        let error_code = ErrorCode::from_i16(i16::decode(buf)?);
        let group_count =
            check_compact_array_len(crate::util::varint::decode_unsigned_varint(buf)?)?;
        let mut groups = Vec::with_capacity(group_count);
        for _ in 0..group_count {
            let group_id = non_nullable_string("group_id", KafkaString::decode_compact(buf)?.0)?;
            let protocol_type =
                non_nullable_string("protocol_type", KafkaString::decode_compact(buf)?.0)?;
            let _ = TaggedFields::decode(buf)?;
            groups.push(ListedGroup {
                group_id,
                protocol_type,
                group_state: None,
                group_type: None,
            });
        }
        let _ = TaggedFields::decode(buf)?;
        Ok(Self {
            throttle_time_ms,
            error_code,
            groups,
        })
    }

    /// Decode from version 4 (adds group_state per group, KIP-518).
    pub fn decode_v4(buf: &mut impl Buf) -> Result<Self> {
        let throttle_time_ms = i32::decode(buf)?;
        let error_code = ErrorCode::from_i16(i16::decode(buf)?);
        let group_count =
            check_compact_array_len(crate::util::varint::decode_unsigned_varint(buf)?)?;
        let mut groups = Vec::with_capacity(group_count);
        for _ in 0..group_count {
            let group_id = non_nullable_string("group_id", KafkaString::decode_compact(buf)?.0)?;
            let protocol_type =
                non_nullable_string("protocol_type", KafkaString::decode_compact(buf)?.0)?;
            let group_state =
                non_nullable_string("group_state", KafkaString::decode_compact(buf)?.0)?;
            let _ = TaggedFields::decode(buf)?;
            groups.push(ListedGroup {
                group_id,
                protocol_type,
                group_state: Some(group_state),
                group_type: None,
            });
        }
        let _ = TaggedFields::decode(buf)?;
        Ok(Self {
            throttle_time_ms,
            error_code,
            groups,
        })
    }

    /// Decode from version 5 (adds group_type per group, KIP-848).
    pub fn decode_v5(buf: &mut impl Buf) -> Result<Self> {
        let throttle_time_ms = i32::decode(buf)?;
        let error_code = ErrorCode::from_i16(i16::decode(buf)?);
        let group_count =
            check_compact_array_len(crate::util::varint::decode_unsigned_varint(buf)?)?;
        let mut groups = Vec::with_capacity(group_count);
        for _ in 0..group_count {
            let group_id = non_nullable_string("group_id", KafkaString::decode_compact(buf)?.0)?;
            let protocol_type =
                non_nullable_string("protocol_type", KafkaString::decode_compact(buf)?.0)?;
            let group_state =
                non_nullable_string("group_state", KafkaString::decode_compact(buf)?.0)?;
            let group_type =
                non_nullable_string("group_type", KafkaString::decode_compact(buf)?.0)?;
            let _ = TaggedFields::decode(buf)?;
            groups.push(ListedGroup {
                group_id,
                protocol_type,
                group_state: Some(group_state),
                group_type: Some(group_type),
            });
        }
        let _ = TaggedFields::decode(buf)?;
        Ok(Self {
            throttle_time_ms,
            error_code,
            groups,
        })
    }
}

impl VersionedEncode for ListGroupsRequest {
    fn encode_versioned(&self, version: i16, buf: &mut impl BufMut) -> Result<()> {
        match version {
            1 | 2 => self.encode_v1(buf)?,
            3 => self.encode_v3(buf)?,
            4 => self.encode_v4(buf)?,
            5 => self.encode_v5(buf)?,
            _ => return unsupported_encode!("ListGroupsRequest", version),
        }
        Ok(())
    }
}

impl VersionedDecode for ListGroupsResponse {
    fn decode_versioned(version: i16, buf: &mut impl Buf) -> Result<Self> {
        match version {
            1 | 2 => Self::decode_v1(buf),
            3 => Self::decode_v3(buf),
            4 => Self::decode_v4(buf),
            5 => Self::decode_v5(buf),
            _ => unsupported_decode!("ListGroupsResponse", version),
        }
    }
}

#[cfg(test)]
#[allow(clippy::unwrap_used, clippy::expect_used, clippy::panic)]
mod tests {
    use super::*;

    use bytes::BytesMut;

    #[test]
    fn test_list_groups_request() {
        let request = ListGroupsRequest {
            states_filter: Vec::new(),
            types_filter: Vec::new(),
        };
        assert_eq!(ListGroupsRequest::api_key(), ApiKey::ListGroups);
        let mut buf = BytesMut::new();
        request.encode_v1(&mut buf).unwrap();
        // ListGroups v1 has an empty body
        assert!(buf.is_empty());
    }

    #[test]
    fn test_list_groups_response_decode_v1() {
        let mut buf = BytesMut::new();
        // throttle_time_ms
        buf.put_i32(0);
        // error_code
        buf.put_i16(0);
        // groups count
        buf.put_i32(2);
        // group 1
        let g1 = "group-a";
        buf.put_i16(g1.len() as i16);
        buf.put_slice(g1.as_bytes());
        let pt1 = "consumer";
        buf.put_i16(pt1.len() as i16);
        buf.put_slice(pt1.as_bytes());
        // group 2
        let g2 = "group-b";
        buf.put_i16(g2.len() as i16);
        buf.put_slice(g2.as_bytes());
        let pt2 = "consumer";
        buf.put_i16(pt2.len() as i16);
        buf.put_slice(pt2.as_bytes());

        let response = ListGroupsResponse::decode_v1(&mut buf.freeze()).unwrap();
        assert!(response.error_code.is_ok());
        assert_eq!(response.groups.len(), 2);
        assert_eq!(response.groups[0].group_id, "group-a");
        assert_eq!(response.groups[1].group_id, "group-b");
        assert_eq!(response.groups[0].group_state, None);
        assert_eq!(response.groups[0].group_type, None);
    }

    #[test]
    fn test_list_groups_request_encode_v3_flexible() {
        let request = ListGroupsRequest {
            states_filter: Vec::new(),
            types_filter: Vec::new(),
        };

        let mut buf_v1 = BytesMut::new();
        request.encode_v1(&mut buf_v1).unwrap();
        assert!(buf_v1.is_empty());

        let mut buf_v3 = BytesMut::new();
        request.encode_v3(&mut buf_v3).unwrap();

        // v3 adds tagged fields (just 0x00 for empty)
        assert_eq!(buf_v3.len(), 1);
        assert_eq!(buf_v3[0], 0x00);
    }

    #[test]
    fn test_list_groups_request_encode_v4_states_filter() {
        let request = ListGroupsRequest {
            states_filter: vec!["Stable".to_string(), "Empty".to_string()],
            types_filter: Vec::new(),
        };

        let mut buf = BytesMut::new();
        request.encode_v4(&mut buf).unwrap();

        // Should contain the state filter strings
        let data = String::from_utf8_lossy(&buf);
        assert!(data.contains("Stable"));
        assert!(data.contains("Empty"));
    }

    #[test]
    fn test_list_groups_request_encode_v5_types_filter() {
        let request = ListGroupsRequest {
            states_filter: vec!["Stable".to_string()],
            types_filter: vec!["classic".to_string(), "consumer".to_string()],
        };

        let mut buf = BytesMut::new();
        request.encode_v5(&mut buf).unwrap();

        let data = String::from_utf8_lossy(&buf);
        assert!(data.contains("Stable"));
        assert!(data.contains("classic"));
        assert!(data.contains("consumer"));
    }

    #[test]
    fn test_list_groups_response_decode_v3_flexible() {
        use bytes::BufMut;
        let mut buf = BytesMut::new();

        buf.put_i32(10); // throttle_time_ms
        buf.put_i16(0); // error_code

        // groups compact array: 1 → varint(2)
        crate::util::varint::encode_unsigned_varint(2, &mut buf);
        {
            // group_id: "grp-1"
            crate::util::varint::encode_unsigned_varint(6, &mut buf);
            buf.put_slice(b"grp-1");
            // protocol_type: "consumer"
            crate::util::varint::encode_unsigned_varint(9, &mut buf);
            buf.put_slice(b"consumer");
            // element tagged fields
            crate::util::varint::encode_unsigned_varint(0, &mut buf);
        }

        // top-level tagged fields
        crate::util::varint::encode_unsigned_varint(0, &mut buf);

        let mut data = buf.freeze();
        let resp = ListGroupsResponse::decode_v3(&mut data).unwrap();

        assert_eq!(resp.throttle_time_ms, 10);
        assert!(resp.error_code.is_ok());
        assert_eq!(resp.groups.len(), 1);
        assert_eq!(resp.groups[0].group_id, "grp-1");
        assert_eq!(resp.groups[0].protocol_type, "consumer");
        assert_eq!(resp.groups[0].group_state, None);
        assert_eq!(resp.groups[0].group_type, None);
    }

    #[test]
    fn test_list_groups_response_decode_v4_group_state() {
        use bytes::BufMut;
        let mut buf = BytesMut::new();

        buf.put_i32(0); // throttle_time_ms
        buf.put_i16(0); // error_code

        // groups compact array: 1 → varint(2)
        crate::util::varint::encode_unsigned_varint(2, &mut buf);
        {
            // group_id: "grp-1"
            crate::util::varint::encode_unsigned_varint(6, &mut buf);
            buf.put_slice(b"grp-1");
            // protocol_type: "consumer"
            crate::util::varint::encode_unsigned_varint(9, &mut buf);
            buf.put_slice(b"consumer");
            // group_state: "Stable"
            crate::util::varint::encode_unsigned_varint(7, &mut buf);
            buf.put_slice(b"Stable");
            // element tagged fields
            crate::util::varint::encode_unsigned_varint(0, &mut buf);
        }

        // top-level tagged fields
        crate::util::varint::encode_unsigned_varint(0, &mut buf);

        let mut data = buf.freeze();
        let resp = ListGroupsResponse::decode_v4(&mut data).unwrap();

        assert_eq!(resp.groups.len(), 1);
        assert_eq!(resp.groups[0].group_state, Some("Stable".to_string()));
        assert_eq!(resp.groups[0].group_type, None);
    }

    #[test]
    fn test_list_groups_response_decode_v5_group_type() {
        use bytes::BufMut;
        let mut buf = BytesMut::new();

        buf.put_i32(0); // throttle_time_ms
        buf.put_i16(0); // error_code

        // groups compact array: 2 → varint(3)
        crate::util::varint::encode_unsigned_varint(3, &mut buf);
        {
            // group 1
            crate::util::varint::encode_unsigned_varint(6, &mut buf);
            buf.put_slice(b"grp-1");
            crate::util::varint::encode_unsigned_varint(9, &mut buf);
            buf.put_slice(b"consumer");
            crate::util::varint::encode_unsigned_varint(7, &mut buf);
            buf.put_slice(b"Stable");
            crate::util::varint::encode_unsigned_varint(8, &mut buf);
            buf.put_slice(b"classic");
            crate::util::varint::encode_unsigned_varint(0, &mut buf);

            // group 2
            crate::util::varint::encode_unsigned_varint(6, &mut buf);
            buf.put_slice(b"grp-2");
            crate::util::varint::encode_unsigned_varint(1, &mut buf); // empty protocol_type
            crate::util::varint::encode_unsigned_varint(6, &mut buf);
            buf.put_slice(b"Empty");
            crate::util::varint::encode_unsigned_varint(9, &mut buf);
            buf.put_slice(b"consumer");
            crate::util::varint::encode_unsigned_varint(0, &mut buf);
        }

        // top-level tagged fields
        crate::util::varint::encode_unsigned_varint(0, &mut buf);

        let mut data = buf.freeze();
        let resp = ListGroupsResponse::decode_v5(&mut data).unwrap();

        assert_eq!(resp.groups.len(), 2);
        assert_eq!(resp.groups[0].group_id, "grp-1");
        assert_eq!(resp.groups[0].group_state, Some("Stable".to_string()));
        assert_eq!(resp.groups[0].group_type, Some("classic".to_string()));
        assert_eq!(resp.groups[1].group_id, "grp-2");
        assert_eq!(resp.groups[1].group_state, Some("Empty".to_string()));
        assert_eq!(resp.groups[1].group_type, Some("consumer".to_string()));
    }
}