azof 0.2.1

Lakehouse format with event time travel
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
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
use crate::{AzofError, Projection};
use arrow::datatypes::{DataType, Field, Schema, TimeUnit};
use arrow_array::builder::{
    BooleanBuilder, Int64Builder, StringBuilder, TimestampMillisecondBuilder,
};
use arrow_array::cast::AsArray;
use arrow_array::types::{Int64Type, TimestampMillisecondType};
use arrow_array::{ArrayRef, RecordBatch};
use serde::{Deserialize, Serialize};
use std::sync::Arc;

pub const KEY_NAME: &str = "key";
pub const EVENT_TIME_NAME: &str = "event_time";

#[derive(Clone, Debug, Serialize, Deserialize, PartialEq)]
pub enum ColumnType {
    String,
    Int,
    Boolean,
    DateTime,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ColumnDef {
    pub name: String,
    pub data_type: ColumnType,
    pub nullable: bool,
}

#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct TableSchema {
    pub columns: Vec<ColumnDef>,
}

pub enum ColumnBuilder {
    String(StringBuilder),
    Int(Int64Builder),
    Boolean(BooleanBuilder),
    DateTime(TimestampMillisecondBuilder),
}

impl ColumnBuilder {
    pub fn new(column_type: &ColumnType) -> Self {
        match column_type {
            ColumnType::String => ColumnBuilder::String(StringBuilder::new()),
            ColumnType::Int => ColumnBuilder::Int(Int64Builder::new()),
            ColumnType::Boolean => ColumnBuilder::Boolean(BooleanBuilder::new()),
            ColumnType::DateTime => {
                ColumnBuilder::DateTime(TimestampMillisecondBuilder::new().with_timezone("UTC"))
            }
        }
    }

    pub fn append_value(&mut self, array: &ArrayRef, row_idx: usize) {
        match self {
            ColumnBuilder::String(builder) => {
                let val_arr = array.as_string::<i32>();
                let val_val = val_arr.value(row_idx);
                builder.append_value(val_val);
            }
            ColumnBuilder::Int(builder) => {
                let val_arr = array.as_primitive::<Int64Type>();
                let val_val = val_arr.value(row_idx);
                builder.append_value(val_val);
            }
            ColumnBuilder::Boolean(builder) => {
                let val_arr = array.as_boolean();
                let val_val = val_arr.value(row_idx);
                builder.append_value(val_val);
            }
            ColumnBuilder::DateTime(builder) => {
                let val_arr = array.as_primitive::<TimestampMillisecondType>();
                let val_val = val_arr.value(row_idx);
                builder.append_value(val_val);
            }
        }
    }

    pub fn append_string(&mut self, data: &str) {
        match self {
            ColumnBuilder::String(builder) => {
                builder.append_value(data);
            }
            _ => panic!("unexpected column type"),
        }
    }

    pub fn append_int(&mut self, data: i64) {
        match self {
            ColumnBuilder::Int(builder) => {
                builder.append_value(data);
            }
            _ => panic!("unexpected column type"),
        }
    }

    pub fn append_boolean(&mut self, data: bool) {
        match self {
            ColumnBuilder::Boolean(builder) => {
                builder.append_value(data);
            }
            _ => panic!("unexpected column type"),
        }
    }

    pub fn append_datetime(&mut self, data: i64) {
        match self {
            ColumnBuilder::DateTime(builder) => {
                builder.append_value(data);
            }
            _ => panic!("unexpected column type"),
        }
    }

    pub fn finish(&mut self) -> ArrayRef {
        match self {
            ColumnBuilder::String(builder) => Arc::new(builder.finish()),
            ColumnBuilder::Int(builder) => Arc::new(builder.finish()),
            ColumnBuilder::Boolean(builder) => Arc::new(builder.finish()),
            ColumnBuilder::DateTime(builder) => Arc::new(builder.finish()),
        }
    }
}

impl TableSchema {
    pub fn column_builders(
        &self,
        projection: &Projection,
    ) -> (
        StringBuilder,
        TimestampMillisecondBuilder,
        Vec<ColumnBuilder>,
    ) {
        let mut column_builders: Vec<ColumnBuilder> = vec![];

        for column in &self.columns {
            if projection.contains(&column.name) {
                column_builders.push(ColumnBuilder::new(&column.data_type));
            }
        }
        (
            StringBuilder::new(),
            TimestampMillisecondBuilder::new().with_timezone("UTC"),
            column_builders,
        )
    }

    pub fn to_batch(
        &self,
        mut keys: StringBuilder,
        mut timestamps: TimestampMillisecondBuilder,
        values: Vec<ColumnBuilder>,
        projection: &Projection,
    ) -> Result<RecordBatch, AzofError> {
        let mut columns: Vec<ArrayRef> = vec![];
        if projection.contains(KEY_NAME) {
            columns.push(Arc::new(keys.finish()));
        }

        if projection.contains(EVENT_TIME_NAME) {
            columns.push(Arc::new(timestamps.finish()));
        }

        for mut builder in values {
            columns.push(builder.finish());
        }

        let schema = Arc::new(self.to_arrow_schema(projection)?);

        Ok(RecordBatch::try_new(schema, columns)?)
    }

    pub fn to_arrow_schema(&self, projection: &Projection) -> Result<Schema, AzofError> {
        let mut fields = Vec::new();

        if projection.contains(KEY_NAME) {
            fields.push(Field::new(KEY_NAME, DataType::Utf8, false));
        }

        if projection.contains(EVENT_TIME_NAME) {
            fields.push(Field::new(
                EVENT_TIME_NAME,
                DataType::Timestamp(TimeUnit::Millisecond, Some("UTC".into())),
                false,
            ));
        }

        for col in &self.columns {
            if projection.contains(&col.name) {
                let arrow_type = match col.data_type {
                    ColumnType::String => DataType::Utf8,
                    ColumnType::Int => DataType::Int64,
                    ColumnType::Boolean => DataType::Boolean,
                    ColumnType::DateTime => {
                        DataType::Timestamp(TimeUnit::Millisecond, Some("UTC".into()))
                    }
                };
                fields.push(Field::new(&col.name, arrow_type, col.nullable));
            }
        }

        Ok(Schema::new(fields))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::Projection::All;
    use arrow_array::{Array, BooleanArray, Int64Array, StringArray, TimestampMillisecondArray};
    use chrono::{TimeZone, Utc};

    #[test]
    fn test_deserialization() {
        let json_str = r#"{
            "columns":[{
                "name": "foo",
                "data_type": "String",
                "nullable": true
            },
            {
                "name": "bar",
                "data_type": "String",
                "nullable": false
            }]
        }
  "#;
        let table_schema: TableSchema = serde_json::from_str(json_str).unwrap();

        assert_eq!(table_schema.columns.len(), 2);

        assert_eq!(table_schema.columns[0].name, "foo".to_string());
        assert_eq!(table_schema.columns[0].data_type, ColumnType::String);
        assert!(table_schema.columns[0].nullable);

        assert_eq!(table_schema.columns[1].name, "bar".to_string());
        assert_eq!(table_schema.columns[1].data_type, ColumnType::String);
        assert!(!table_schema.columns[1].nullable);
    }

    #[test]
    fn test_to_arrow_schema() {
        let json_str = r#"{
            "columns":[{
                "name":"foo",
                "data_type":"String",
                "nullable":true
            },
            {
                "name":"bar",
                "data_type":"Int",
                "nullable":false
            },
            {
                "name":"flag",
                "data_type":"Boolean",
                "nullable":false
            },
            {
                "name":"created_at",
                "data_type":"DateTime",
                "nullable":false
            }]
        }
  "#;
        let table_schema: TableSchema = serde_json::from_str(json_str).unwrap();

        let arrow_schema = table_schema.to_arrow_schema(&All).unwrap();

        assert_eq!(
            arrow_schema,
            Schema::new(vec![
                Field::new("key", DataType::Utf8, false),
                Field::new(
                    "event_time",
                    DataType::Timestamp(TimeUnit::Millisecond, Some("UTC".into())),
                    false,
                ),
                Field::new("foo", DataType::Utf8, true),
                Field::new("bar", DataType::Int64, false),
                Field::new("flag", DataType::Boolean, false),
                Field::new(
                    "created_at",
                    DataType::Timestamp(TimeUnit::Millisecond, Some("UTC".into())),
                    false
                ),
            ])
        );
    }

    #[test]
    fn test_column_builder_creation() {
        let string_builder = ColumnBuilder::new(&ColumnType::String);
        let int_builder = ColumnBuilder::new(&ColumnType::Int);
        let bool_builder = ColumnBuilder::new(&ColumnType::Boolean);
        let date_builder = ColumnBuilder::new(&ColumnType::DateTime);

        match string_builder {
            ColumnBuilder::String(_) => {}
            _ => panic!("Expected String builder"),
        }

        match int_builder {
            ColumnBuilder::Int(_) => {}
            _ => panic!("Expected Int builder"),
        }

        match bool_builder {
            ColumnBuilder::Boolean(_) => {}
            _ => panic!("Expected Boolean builder"),
        }

        match date_builder {
            ColumnBuilder::DateTime(_) => {}
            _ => panic!("Expected DateTime builder"),
        }
    }

    #[test]
    fn test_append_string_to_builder() {
        let mut string_builder = ColumnBuilder::new(&ColumnType::String);

        string_builder.append_string("test1");
        string_builder.append_string("test2");
        string_builder.append_string("test3");

        let array = string_builder.finish();
        let string_array = array.as_string::<i32>();

        assert_eq!(string_array.len(), 3);
        assert_eq!(string_array.value(0), "test1");
        assert_eq!(string_array.value(1), "test2");
        assert_eq!(string_array.value(2), "test3");
    }

    #[test]
    #[should_panic(expected = "unexpected column type")]
    fn test_append_string_to_wrong_builder() {
        let mut int_builder = ColumnBuilder::new(&ColumnType::Int);

        int_builder.append_string("test");

        let mut string_builder = ColumnBuilder::new(&ColumnType::String);

        string_builder.append_int(134);
    }

    #[test]
    fn test_append_value_from_array() {
        let string_array: ArrayRef = Arc::new(StringArray::from(vec!["str1", "str2", "str3"]));
        let int_array: ArrayRef = Arc::new(Int64Array::from(vec![100, 200, 300]));
        let bool_array: ArrayRef = Arc::new(BooleanArray::from(vec![true, false, true]));

        let date1 = Utc
            .with_ymd_and_hms(2023, 1, 1, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        let date2 = Utc
            .with_ymd_and_hms(2023, 2, 1, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        let date3 = Utc
            .with_ymd_and_hms(2023, 3, 1, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        let date_array: ArrayRef =
            Arc::new(TimestampMillisecondArray::from(vec![date1, date2, date3]));

        let mut string_builder = ColumnBuilder::new(&ColumnType::String);
        string_builder.append_value(&string_array, 0);
        string_builder.append_value(&string_array, 2);
        let result = string_builder.finish();
        let result_array = result.as_string::<i32>();
        assert_eq!(result_array.len(), 2);
        assert_eq!(result_array.value(0), "str1");
        assert_eq!(result_array.value(1), "str3");

        let mut int_builder = ColumnBuilder::new(&ColumnType::Int);
        int_builder.append_value(&int_array, 1);
        int_builder.append_value(&int_array, 2);
        let result = int_builder.finish();
        let result_array = result.as_primitive::<Int64Type>();
        assert_eq!(result_array.len(), 2);
        assert_eq!(result_array.value(0), 200);
        assert_eq!(result_array.value(1), 300);

        let mut bool_builder = ColumnBuilder::new(&ColumnType::Boolean);
        bool_builder.append_value(&bool_array, 0);
        bool_builder.append_value(&bool_array, 1);
        bool_builder.append_value(&bool_array, 2);
        let result = bool_builder.finish();
        let result_array = result.as_boolean();
        assert_eq!(result_array.len(), 3);
        assert!(result_array.value(0));
        assert!(!result_array.value(1));
        assert!(result_array.value(2));

        let mut date_builder = ColumnBuilder::new(&ColumnType::DateTime);
        date_builder.append_value(&date_array, 0);
        date_builder.append_value(&date_array, 2);
        let result = date_builder.finish();
        let result_array = result.as_primitive::<TimestampMillisecondType>();
        assert_eq!(result_array.len(), 2);
        assert_eq!(result_array.value(0), date1);
        assert_eq!(result_array.value(1), date3);
    }

    #[test]
    fn test_mixed_column_batch() {
        let schema = TableSchema {
            columns: vec![
                ColumnDef {
                    name: "string_col".to_string(),
                    data_type: ColumnType::String,
                    nullable: false,
                },
                ColumnDef {
                    name: "int_col".to_string(),
                    data_type: ColumnType::Int,
                    nullable: false,
                },
                ColumnDef {
                    name: "bool_col".to_string(),
                    data_type: ColumnType::Boolean,
                    nullable: false,
                },
                ColumnDef {
                    name: "date_col".to_string(),
                    data_type: ColumnType::DateTime,
                    nullable: false,
                },
            ],
        };

        let (mut keys, mut timestamps, mut value_builders) = schema.column_builders(&All);

        keys.append_value("key1");
        keys.append_value("key2");

        let ts1 = Utc
            .with_ymd_and_hms(2023, 1, 10, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        let ts2 = Utc
            .with_ymd_and_hms(2023, 2, 10, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        timestamps.append_value(ts1);
        timestamps.append_value(ts2);

        value_builders[0].append_string("string1");
        value_builders[0].append_string("string2");

        let int_array: ArrayRef = Arc::new(Int64Array::from(vec![100, 200]));
        let bool_array: ArrayRef = Arc::new(BooleanArray::from(vec![true, false]));
        let date1 = Utc
            .with_ymd_and_hms(2023, 1, 1, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        let date2 = Utc
            .with_ymd_and_hms(2023, 2, 1, 0, 0, 0)
            .unwrap()
            .timestamp_millis();
        let date_array: ArrayRef = Arc::new(TimestampMillisecondArray::from(vec![date1, date2]));

        value_builders[1].append_value(&int_array, 0);
        value_builders[1].append_value(&int_array, 1);

        value_builders[2].append_value(&bool_array, 0);
        value_builders[2].append_value(&bool_array, 1);

        value_builders[3].append_value(&date_array, 0);
        value_builders[3].append_value(&date_array, 1);

        let batch = schema
            .to_batch(keys, timestamps, value_builders, &All)
            .unwrap();

        let arrow_schema = batch.schema();
        assert_eq!(arrow_schema.fields().len(), 6); // key + 4 columns + event_time
        assert_eq!(arrow_schema.field(0).name(), "key");
        assert_eq!(arrow_schema.field(0).data_type(), &DataType::Utf8);

        assert_eq!(arrow_schema.field(1).name(), "event_time");

        assert_eq!(arrow_schema.field(2).name(), "string_col");
        assert_eq!(arrow_schema.field(2).data_type(), &DataType::Utf8);
        assert_eq!(arrow_schema.field(3).name(), "int_col");
        assert_eq!(arrow_schema.field(3).data_type(), &DataType::Int64);
        assert_eq!(arrow_schema.field(4).name(), "bool_col");
        assert_eq!(arrow_schema.field(4).data_type(), &DataType::Boolean);
        assert_eq!(arrow_schema.field(5).name(), "date_col");
        assert_eq!(
            arrow_schema.field(5).data_type(),
            &DataType::Timestamp(TimeUnit::Millisecond, Some("UTC".into()))
        );

        assert_eq!(batch.num_rows(), 2);

        let key_array = batch.column(0).as_string::<i32>();
        assert_eq!(key_array.value(0), "key1");
        assert_eq!(key_array.value(1), "key2");

        let ts_array = batch.column(1).as_primitive::<TimestampMillisecondType>();
        assert_eq!(ts_array.value(0), ts1);
        assert_eq!(ts_array.value(1), ts2);

        let string_array = batch.column(2).as_string::<i32>();
        assert_eq!(string_array.value(0), "string1");
        assert_eq!(string_array.value(1), "string2");

        let int_array = batch.column(3).as_primitive::<Int64Type>();
        assert_eq!(int_array.value(0), 100);
        assert_eq!(int_array.value(1), 200);

        let bool_array = batch.column(4).as_boolean();
        assert!(bool_array.value(0));
        assert!(!bool_array.value(1));

        let date_array = batch.column(5).as_primitive::<TimestampMillisecondType>();
        assert_eq!(date_array.value(0), date1);
        assert_eq!(date_array.value(1), date2);
    }
}