generator.explores.explore

  1"""Generic explore type."""
  2
  3from __future__ import annotations
  4
  5from dataclasses import dataclass, field
  6from pathlib import Path
  7from typing import Any, Dict, List, Optional, Tuple
  8
  9import lkml
 10
 11from ..views.lookml_utils import escape_filter_expr, slug_to_title
 12
 13
 14@dataclass
 15class Explore:
 16    """A generic explore."""
 17
 18    name: str
 19    views: Dict[str, str]
 20    views_path: Optional[Path] = None
 21    defn: Optional[Dict[str, str]] = None
 22    type: str = field(init=False)
 23
 24    def to_dict(self) -> dict:
 25        """Explore instance represented as a dict."""
 26        return {self.name: {"type": self.type, "views": self.views}}
 27
 28    def to_lookml(
 29        self, v1_name: Optional[str], hidden: Optional[bool]
 30    ) -> List[Dict[str, Any]]:
 31        """
 32        Generate LookML for this explore.
 33
 34        Any generation done in dependent explore's
 35        `_to_lookml` takes precedence over these fields.
 36        """
 37        base_lookml = {}
 38        if hidden:
 39            base_lookml["hidden"] = "yes"
 40        base_view_name = next(
 41            (
 42                view_name
 43                for view_type, view_name in self.views.items()
 44                if view_type == "base_view"
 45            )
 46        )
 47        for view_type, view in self.views.items():
 48            # We look at our dependent views to see if they have a
 49            # "submission" field. Dependent views are any that are:
 50            # - base_view
 51            # - extended_view*
 52            #
 53            # We do not want to look at joined views. Those should be
 54            # labeled as:
 55            # - join*
 56            #
 57            # If they have a submission field, we filter on the date.
 58            # This allows for filter queries to succeed.
 59            if "join" in view_type:
 60                continue
 61            if time_partitioning_group := self.get_view_time_partitioning_group(view):
 62                base_lookml["sql_always_where"] = (
 63                    f"${{{base_view_name}.{time_partitioning_group}_date}} >= '2010-01-01'"
 64                )
 65
 66        # We only update the first returned explore
 67        new_lookml = self._to_lookml(v1_name)
 68        base_lookml.update(new_lookml[0])
 69        new_lookml[0] = base_lookml
 70
 71        return new_lookml
 72
 73    def _to_lookml(
 74        self,
 75        v1_name: Optional[str],
 76    ) -> List[Dict[str, Any]]:
 77        raise NotImplementedError("Only implemented in subclasses")
 78
 79    def get_dependent_views(self) -> List[str]:
 80        """Get views this explore is dependent on."""
 81        dependent_views = []
 82        for _type, views in self.views.items():
 83            if _type.startswith("extended"):
 84                continue
 85            elif _type.startswith("joined"):
 86                dependent_views += [view for view in views]
 87            else:
 88                dependent_views.append(views)
 89        return dependent_views
 90
 91    @staticmethod
 92    def from_dict(name: str, defn: dict, views_path: Path) -> Explore:
 93        """Get an instance of an explore from a namespace definition."""
 94        raise NotImplementedError("Only implemented in subclasses")
 95
 96    def get_view_lookml(self, view: str) -> dict:
 97        """Get the LookML for a view."""
 98        if self.views_path is not None:
 99            return lkml.load((self.views_path / f"{view}.view.lkml").read_text())
100        raise Exception("Missing view path for get_view_lookml")
101
102    def get_datagroup(self) -> Optional[str]:
103        """
104        Return the name of the associated datagroup.
105
106        Return `None` if there is no datagroup for this explore.
107        """
108        return None
109
110    def get_unnested_fields_joins_lookml(
111        self,
112    ) -> list:
113        """Get the LookML for joining unnested fields."""
114        views_lookml = self.get_view_lookml(self.views["base_view"])
115        views: List[str] = [view["name"] for view in views_lookml["views"]]
116        parent_base_name = views_lookml["views"][0]["name"]
117
118        extended_views: List[str] = []
119        if "extended_view" in self.views:
120            # check for extended views
121            extended_views_lookml = self.get_view_lookml(self.views["extended_view"])
122            extended_views = [view["name"] for view in extended_views_lookml["views"]]
123
124            views_lookml.update(extended_views_lookml)
125            views += extended_views
126
127        joins = []
128        for view in views_lookml["views"][1:]:
129            view_name = view["name"]
130            # get repeated, nested fields that exist as separate views in lookml
131            base_name, metric = self._get_base_name_and_metric(
132                view_name=view_name, views=views
133            )
134            metric_name = view_name
135            metric_label = slug_to_title(metric_name)
136
137            if view_name in extended_views:
138                # names of extended views are overriden by the name of the view that is extending them
139                metric_label = slug_to_title(
140                    metric_name.replace(base_name, parent_base_name)
141                )
142                base_name = parent_base_name
143
144            joins.append(
145                {
146                    "name": view_name,
147                    "view_label": metric_label,
148                    "relationship": "one_to_many",
149                    "sql": (
150                        f"LEFT JOIN UNNEST(${{{base_name}.{metric}}}) AS {metric_name} "
151                    ),
152                }
153            )
154
155        return joins
156
157    def _get_default_channel(self, view: str) -> Optional[str]:
158        channel_params = [
159            param
160            for _view_defn in self.get_view_lookml(view)["views"]
161            for param in _view_defn.get("filters", [])
162            if _view_defn["name"] == view and param["name"] == "channel"
163        ]
164
165        if channel_params:
166            allowed_values = channel_params[0]["suggestions"]
167            default_value = allowed_values[0]
168            return escape_filter_expr(default_value)
169        return None
170
171    def _get_base_name_and_metric(
172        self, view_name: str, views: List[str]
173    ) -> Tuple[str, str]:
174        """
175        Get base view and metric names.
176
177        Returns the the name of the base view and the metric based on the
178        passed `view_name` and existing views.
179
180        The names are resolved in a backwards fashion to account for
181        repeated nested fields that might contain other nested fields.
182        For example:
183
184        view: sync {
185            [...]
186            dimension: payload__events {
187                sql: ${TABLE}.payload.events ;;
188            }
189        }
190
191        view: sync__payload__events {
192            [...]
193            dimension: f5_ {
194                sql: ${TABLE}.f5_ ;;
195            }
196        }
197
198        view: sync__payload__events__f5_ {
199            [...]
200        }
201
202        For these nested views to get translated to the following joins, the names
203        need to be resolved backwards:
204
205        join: sync__payload__events {
206            relationship: one_to_many
207            sql: LEFT JOIN UNNEST(${sync.payload__events}) AS sync__payload__events ;;
208        }
209
210        join: sync__payload__events__f5_ {
211            relationship: one_to_many
212            sql: LEFT JOIN UNNEST(${sync__payload__events.f5_}) AS sync__payload__events__f5_ ;;
213        }
214        """
215        split = view_name.split("__")
216        for index in range(len(split) - 1, 0, -1):
217            base_view = "__".join(split[:index])
218            metric = "__".join(split[index:])
219            if base_view in views:
220                return (base_view, metric)
221        raise Exception(f"Cannot get base name and metric from view {view_name}")
222
223    def has_view_dimension(self, view: str, dimension_name: str) -> bool:
224        """Determine whether a this view has this dimension."""
225        for _view_defn in self.get_view_lookml(view)["views"]:
226            if _view_defn["name"] != view:
227                continue
228            for dim in _view_defn.get("dimensions", []):
229                if dim["name"] == dimension_name:
230                    return True
231        return False
232
233    def get_view_time_partitioning_group(self, view: str) -> Optional[str]:
234        """Get time partitiong dimension group for this view.
235
236        Return the name of the first dimension group tagged "time_partitioning_field",
237        and fall back to "submission" if available.
238        """
239        has_submission = False
240        for _view_defn in self.get_view_lookml(view)["views"]:
241            if not _view_defn["name"] == view:
242                continue
243            for dim in _view_defn.get("dimension_groups", []):
244                if "time_partitioning_field" in dim.get("tags", []):
245                    return dim["name"]
246                elif dim["name"] == "submission":
247                    has_submission = True
248        if has_submission:
249            return "submission"
250        return None
251
252    def get_required_filters(self, view_name: str) -> List[Dict[str, str]]:
253        """Get required filters for this view."""
254        filters = []
255        view = self.views[view_name]
256
257        # Add a default filter on channel, if it's present in the view
258        default_channel = self._get_default_channel(view)
259        if default_channel is not None:
260            filters.append({"channel": default_channel})
261
262        # Add submission filter, if present in the view
263        if time_partitioning_group := self.get_view_time_partitioning_group(view):
264            filters.append({f"{time_partitioning_group}_date": "28 days"})
265
266        return filters
267
268    def __eq__(self, other) -> bool:
269        """Check for equality with other View."""
270
271        def comparable_dict(d):
272            return tuple(sorted(d.items()))
273
274        if isinstance(other, Explore):
275            return (
276                self.name == other.name
277                and comparable_dict(self.views) == comparable_dict(other.views)
278                and self.type == other.type
279            )
280        return False