263 lines
8.3 KiB
Python
263 lines
8.3 KiB
Python
from __future__ import annotations
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import json
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import typing as t
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from dataclasses import dataclass, field
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from sqlglot import Schema, exp, maybe_parse
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from sqlglot.errors import SqlglotError
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from sqlglot.optimizer import Scope, build_scope, qualify
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if t.TYPE_CHECKING:
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from sqlglot.dialects.dialect import DialectType
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@dataclass(frozen=True)
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class Node:
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name: str
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expression: exp.Expression
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source: exp.Expression
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downstream: t.List[Node] = field(default_factory=list)
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alias: str = ""
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def walk(self) -> t.Iterator[Node]:
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yield self
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for d in self.downstream:
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if isinstance(d, Node):
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yield from d.walk()
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else:
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yield d
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def to_html(self, **opts) -> LineageHTML:
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return LineageHTML(self, **opts)
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def lineage(
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column: str | exp.Column,
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sql: str | exp.Expression,
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schema: t.Optional[t.Dict | Schema] = None,
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sources: t.Optional[t.Dict[str, str | exp.Subqueryable]] = None,
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dialect: DialectType = None,
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**kwargs,
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) -> Node:
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"""Build the lineage graph for a column of a SQL query.
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Args:
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column: The column to build the lineage for.
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sql: The SQL string or expression.
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schema: The schema of tables.
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sources: A mapping of queries which will be used to continue building lineage.
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dialect: The dialect of input SQL.
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**kwargs: Qualification optimizer kwargs.
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Returns:
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A lineage node.
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"""
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expression = maybe_parse(sql, dialect=dialect)
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if sources:
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expression = exp.expand(
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expression,
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{
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k: t.cast(exp.Subqueryable, maybe_parse(v, dialect=dialect))
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for k, v in sources.items()
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},
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)
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qualified = qualify.qualify(
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expression,
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dialect=dialect,
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schema=schema,
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**{"validate_qualify_columns": False, "identify": False, **kwargs}, # type: ignore
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)
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scope = build_scope(qualified)
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if not scope:
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raise SqlglotError("Cannot build lineage, sql must be SELECT")
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def to_node(
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column_name: str,
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scope: Scope,
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scope_name: t.Optional[str] = None,
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upstream: t.Optional[Node] = None,
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alias: t.Optional[str] = None,
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) -> Node:
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aliases = {
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dt.alias: dt.comments[0].split()[1]
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for dt in scope.derived_tables
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if dt.comments and dt.comments[0].startswith("source: ")
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}
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if isinstance(scope.expression, exp.Union):
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for scope in scope.union_scopes:
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node = to_node(
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column_name,
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scope=scope,
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scope_name=scope_name,
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upstream=upstream,
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alias=aliases.get(scope_name),
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)
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return node
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# Find the specific select clause that is the source of the column we want.
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# This can either be a specific, named select or a generic `*` clause.
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select = next(
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(select for select in scope.selects if select.alias_or_name == column_name),
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exp.Star() if scope.expression.is_star else None,
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)
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if not select:
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raise ValueError(f"Could not find {column_name} in {scope.expression}")
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if isinstance(scope.expression, exp.Select):
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# For better ergonomics in our node labels, replace the full select with
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# a version that has only the column we care about.
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# "x", SELECT x, y FROM foo
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# => "x", SELECT x FROM foo
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source = t.cast(exp.Expression, scope.expression.select(select, append=False))
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else:
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source = scope.expression
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# Create the node for this step in the lineage chain, and attach it to the previous one.
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node = Node(
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name=f"{scope_name}.{column_name}" if scope_name else column_name,
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source=source,
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expression=select,
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alias=alias or "",
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)
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if upstream:
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upstream.downstream.append(node)
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# Find all columns that went into creating this one to list their lineage nodes.
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for c in set(select.find_all(exp.Column)):
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table = c.table
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source = scope.sources.get(table)
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if isinstance(source, Scope):
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# The table itself came from a more specific scope. Recurse into that one using the unaliased column name.
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to_node(
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c.name, scope=source, scope_name=table, upstream=node, alias=aliases.get(table)
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)
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else:
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# The source is not a scope - we've reached the end of the line. At this point, if a source is not found
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# it means this column's lineage is unknown. This can happen if the definition of a source used in a query
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# is not passed into the `sources` map.
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source = source or exp.Placeholder()
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node.downstream.append(Node(name=c.sql(), source=source, expression=source))
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return node
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return to_node(column if isinstance(column, str) else column.name, scope)
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class LineageHTML:
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"""Node to HTML generator using vis.js.
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https://visjs.github.io/vis-network/docs/network/
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"""
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def __init__(
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self,
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node: Node,
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dialect: DialectType = None,
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imports: bool = True,
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**opts: t.Any,
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):
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self.node = node
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self.imports = imports
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self.options = {
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"height": "500px",
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"width": "100%",
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"layout": {
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"hierarchical": {
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"enabled": True,
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"nodeSpacing": 200,
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"sortMethod": "directed",
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},
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},
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"interaction": {
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"dragNodes": False,
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"selectable": False,
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},
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"physics": {
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"enabled": False,
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},
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"edges": {
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"arrows": "to",
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},
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"nodes": {
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"font": "20px monaco",
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"shape": "box",
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"widthConstraint": {
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"maximum": 300,
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},
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},
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**opts,
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}
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self.nodes = {}
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self.edges = []
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for node in node.walk():
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if isinstance(node.expression, exp.Table):
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label = f"FROM {node.expression.this}"
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title = f"<pre>SELECT {node.name} FROM {node.expression.this}</pre>"
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group = 1
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else:
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label = node.expression.sql(pretty=True, dialect=dialect)
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source = node.source.transform(
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lambda n: exp.Tag(this=n, prefix="<b>", postfix="</b>")
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if n is node.expression
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else n,
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copy=False,
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).sql(pretty=True, dialect=dialect)
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title = f"<pre>{source}</pre>"
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group = 0
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node_id = id(node)
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self.nodes[node_id] = {
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"id": node_id,
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"label": label,
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"title": title,
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"group": group,
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}
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for d in node.downstream:
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self.edges.append({"from": node_id, "to": id(d)})
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def __str__(self):
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nodes = json.dumps(list(self.nodes.values()))
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edges = json.dumps(self.edges)
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options = json.dumps(self.options)
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imports = (
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"""<script type="text/javascript" src="https://unpkg.com/vis-data@latest/peer/umd/vis-data.min.js"></script>
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<script type="text/javascript" src="https://unpkg.com/vis-network@latest/peer/umd/vis-network.min.js"></script>
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<link rel="stylesheet" type="text/css" href="https://unpkg.com/vis-network/styles/vis-network.min.css" />"""
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if self.imports
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else ""
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)
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return f"""<div>
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<div id="sqlglot-lineage"></div>
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{imports}
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<script type="text/javascript">
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var nodes = new vis.DataSet({nodes})
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nodes.forEach(row => row["title"] = new DOMParser().parseFromString(row["title"], "text/html").body.childNodes[0])
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new vis.Network(
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document.getElementById("sqlglot-lineage"),
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{{
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nodes: nodes,
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edges: new vis.DataSet({edges})
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}},
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{options},
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)
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</script>
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</div>"""
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def _repr_html_(self) -> str:
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return self.__str__()
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