From 24e7ffb289fcc7e7f76a0a18ea17259ef07f7a01 Mon Sep 17 00:00:00 2001
From: Sarah Hoffmann <lonvia@denofr.de>
Date: Sat, 11 Feb 2023 20:42:24 +0100
Subject: [PATCH] add HTML-formatted debug output to lookup

---
 nominatim/api/connection.py     |   7 +-
 nominatim/api/logging.py        | 200 ++++++++++++++++++++++++++++++++
 nominatim/api/lookup.py         |  11 ++
 nominatim/api/results.py        |   6 +
 nominatim/api/v1/server_glue.py |  22 +++-
 5 files changed, 242 insertions(+), 4 deletions(-)
 create mode 100644 nominatim/api/logging.py

diff --git a/nominatim/api/connection.py b/nominatim/api/connection.py
index 79a5e347..efa4490e 100644
--- a/nominatim/api/connection.py
+++ b/nominatim/api/connection.py
@@ -13,6 +13,7 @@ import sqlalchemy as sa
 from sqlalchemy.ext.asyncio import AsyncConnection
 
 from nominatim.db.sqlalchemy_schema import SearchTables
+from nominatim.api.logging import log
 
 class SearchConnection:
     """ An extended SQLAlchemy connection class, that also contains
@@ -34,14 +35,16 @@ class SearchConnection:
                     ) -> Any:
         """ Execute a 'scalar()' query on the connection.
         """
+        log().sql(self.connection, sql)
         return await self.connection.scalar(sql, params)
 
 
-    async def execute(self, sql: sa.sql.base.Executable,
+    async def execute(self, sql: 'sa.Executable',
                       params: Union[Mapping[str, Any], Sequence[Mapping[str, Any]], None] = None
-                     ) -> 'sa.engine.Result[Any]':
+                     ) -> 'sa.Result[Any]':
         """ Execute a 'execute()' query on the connection.
         """
+        log().sql(self.connection, sql)
         return await self.connection.execute(sql, params)
 
 
diff --git a/nominatim/api/logging.py b/nominatim/api/logging.py
new file mode 100644
index 00000000..3949fdae
--- /dev/null
+++ b/nominatim/api/logging.py
@@ -0,0 +1,200 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This file is part of Nominatim. (https://nominatim.org)
+#
+# Copyright (C) 2023 by the Nominatim developer community.
+# For a full list of authors see the git log.
+"""
+Functions for specialised logging with HTML output.
+"""
+from typing import Any, Optional, cast
+from contextvars import ContextVar
+import io
+
+import sqlalchemy as sa
+from sqlalchemy.ext.asyncio import AsyncConnection
+
+try:
+    from pygments import highlight
+    from pygments.lexers import PythonLexer, PostgresLexer
+    from pygments.formatters import HtmlFormatter
+    CODE_HIGHLIGHT = True
+except ModuleNotFoundError:
+    CODE_HIGHLIGHT = False
+
+
+class BaseLogger:
+    """ Interface for logging function.
+
+        The base implementation does nothing. Overwrite the functions
+        in derived classes which implement logging functionality.
+    """
+    def get_buffer(self) -> str:
+        return ''
+
+    def function(self, func: str, **kwargs: Any) -> None:
+        """ Start a new debug chapter for the given function and its parameters.
+        """
+
+
+    def section(self, heading: str) -> None:
+        """ Start a new section with the given title.
+        """
+
+
+    def comment(self, text: str) -> None:
+        """ Add a simple comment to the debug output.
+        """
+
+
+    def var_dump(self, heading: str, var: Any) -> None:
+        """ Print the content of the variable to the debug output prefixed by
+            the given heading.
+        """
+
+
+    def sql(self, conn: AsyncConnection, statement: 'sa.Executable') -> None:
+        """ Print the SQL for the given statement.
+        """
+
+
+class HTMLLogger(BaseLogger):
+    """ Logger that formats messages in HTML.
+    """
+    def __init__(self):
+        self.buffer = io.StringIO()
+
+
+    def get_buffer(self) -> str:
+        return HTML_HEADER + self.buffer.getvalue() + HTML_FOOTER
+
+    def function(self, func: str, **kwargs: Any) -> None:
+        """ Start a new debug chapter for the given function and its parameters.
+        """
+        self._write(f"<h1>Debug output for {func}()</h1>\n<p>Parameters:<dl>")
+        for name, value in kwargs.items():
+            self._write(f'<dt>{name}</dt><dd>{self._python_var(value)}</dd>')
+        self._write('</dl></p>')
+
+
+    def section(self, heading: str) -> None:
+        """ Start a new section with the given title.
+        """
+        self._write(f"<h2>{heading}</h2>")
+
+    def comment(self, text: str) -> None:
+        """ Add a simple comment to the debug output.
+        """
+        self._write(f"<p>{text}</p>")
+
+    def var_dump(self, heading: str, var: Any) -> None:
+        """ Print the content of the variable to the debug output prefixed by
+            the given heading.
+        """
+        self._write(f'<h5>{heading}</h5>{self._python_var(var)}')
+
+
+    def sql(self, conn: AsyncConnection, statement: 'sa.Executable') -> None:
+        """ Dump the SQL statement to debug output.
+        """
+        sqlstr = str(cast('sa.ClauseElement', statement)
+                      .compile(conn.sync_engine, compile_kwargs={"literal_binds": True}))
+        if CODE_HIGHLIGHT:
+            sqlstr = highlight(sqlstr, PostgresLexer(),
+                               HtmlFormatter(nowrap=True, lineseparator='<br>'))
+            self._write(f'<div class="highlight"><code class="lang-sql">{sqlstr}</code></div>')
+        else:
+            self._write(f'<code class="lang-sql">{sqlstr}</code>')
+
+
+    def _python_var(self, var: Any) -> str:
+        if CODE_HIGHLIGHT:
+            fmt = highlight(repr(var), PythonLexer(), HtmlFormatter(nowrap=True))
+            return f'<div class="highlight"><code class="lang-python">{fmt}</code></div>'
+
+        return f'<code class="lang-python">{str(var)}</code>'
+
+
+    def _write(self, text: str) -> None:
+        """ Add the raw text to the debug output.
+        """
+        self.buffer.write(text)
+
+
+logger: ContextVar[BaseLogger] = ContextVar('logger', default=BaseLogger())
+
+
+def set_log_output(fmt: str) -> None:
+    """ Enable collecting debug information.
+    """
+    if fmt == 'html':
+        logger.set(HTMLLogger())
+    elif fmt == 'text':
+        logger.set(TextLogger())
+    else:
+        logger.set(BaseLogger())
+
+
+def log() -> BaseLogger:
+    """ Return the logger for the current context.
+    """
+    return logger.get()
+
+
+def get_and_disable() -> str:
+    """ Return the current content of the debug buffer and disable logging.
+    """
+    buf = logger.get().get_buffer()
+    logger.set(BaseLogger())
+    return buf
+
+
+HTML_HEADER: str = """<!DOCTYPE html>
+<html>
+<head>
+  <title>Nominatim - Debug</title>
+  <style>
+""" + \
+(HtmlFormatter(nobackground=True).get_style_defs('.highlight') if CODE_HIGHLIGHT else '') +\
+"""
+    h2 { font-size: x-large }
+
+    dl {
+      padding-left: 10pt;
+      font-family: monospace
+    }
+
+    dt {
+      float: left;
+      font-weight: bold;
+      margin-right: 0.5em
+    }
+
+    dt::after { content: ": "; }
+
+    dd::after {
+      clear: left;
+      display: block
+    }
+
+    .lang-sql {
+      color: #555;
+      font-size: small
+    }
+
+    h5 {
+        border: solid lightgrey 0.1pt;
+        margin-bottom: 0;
+        background-color: #f7f7f7
+    }
+
+    h5 + .highlight {
+        padding: 3pt;
+        border: solid lightgrey 0.1pt
+    }
+  </style>
+</head>
+<body>
+"""
+
+HTML_FOOTER: str = "</body></html>"
diff --git a/nominatim/api/lookup.py b/nominatim/api/lookup.py
index 56a41310..27706ff3 100644
--- a/nominatim/api/lookup.py
+++ b/nominatim/api/lookup.py
@@ -15,6 +15,7 @@ from nominatim.typing import SaColumn, SaLabel, SaRow
 from nominatim.api.connection import SearchConnection
 import nominatim.api.types as ntyp
 import nominatim.api.results as nres
+from nominatim.api.logging import log
 
 def _select_column_geometry(column: SaColumn,
                             geometry_output: ntyp.GeometryFormat) -> SaLabel:
@@ -36,6 +37,7 @@ async def find_in_placex(conn: SearchConnection, place: ntyp.PlaceRef,
     """ Search for the given place in the placex table and return the
         base information.
     """
+    log().section("Find in placex table")
     t = conn.t.placex
     sql = sa.select(t.c.place_id, t.c.osm_type, t.c.osm_id, t.c.name,
                     t.c.class_, t.c.type, t.c.admin_level,
@@ -69,6 +71,7 @@ async def find_in_osmline(conn: SearchConnection, place: ntyp.PlaceRef,
     """ Search for the given place in the osmline table and return the
         base information.
     """
+    log().section("Find in interpolation table")
     t = conn.t.osmline
     sql = sa.select(t.c.place_id, t.c.osm_id, t.c.parent_place_id,
                     t.c.indexed_date, t.c.startnumber, t.c.endnumber,
@@ -98,6 +101,7 @@ async def find_in_tiger(conn: SearchConnection, place: ntyp.PlaceRef,
     """ Search for the given place in the table of Tiger addresses and return
         the base information. Only lookup by place ID is supported.
     """
+    log().section("Find in TIGER table")
     t = conn.t.tiger
     sql = sa.select(t.c.place_id, t.c.parent_place_id,
                     t.c.startnumber, t.c.endnumber, t.c.step,
@@ -119,6 +123,7 @@ async def find_in_postcode(conn: SearchConnection, place: ntyp.PlaceRef,
     """ Search for the given place in the postcode table and return the
         base information. Only lookup by place ID is supported.
     """
+    log().section("Find in postcode table")
     t = conn.t.postcode
     sql = sa.select(t.c.place_id, t.c.parent_place_id,
                     t.c.rank_search, t.c.rank_address,
@@ -139,30 +144,36 @@ async def get_place_by_id(conn: SearchConnection, place: ntyp.PlaceRef,
                           details: ntyp.LookupDetails) -> Optional[nres.SearchResult]:
     """ Retrieve a place with additional details from the database.
     """
+    log().function('get_place_by_id', place=place, details=details)
+
     if details.geometry_output and details.geometry_output != ntyp.GeometryFormat.GEOJSON:
         raise ValueError("lookup only supports geojosn polygon output.")
 
     row = await find_in_placex(conn, place, details)
     if row is not None:
         result = nres.create_from_placex_row(row)
+        log().var_dump('Result', result)
         await nres.add_result_details(conn, result, details)
         return result
 
     row = await find_in_osmline(conn, place, details)
     if row is not None:
         result = nres.create_from_osmline_row(row)
+        log().var_dump('Result', result)
         await nres.add_result_details(conn, result, details)
         return result
 
     row = await find_in_postcode(conn, place, details)
     if row is not None:
         result = nres.create_from_postcode_row(row)
+        log().var_dump('Result', result)
         await nres.add_result_details(conn, result, details)
         return result
 
     row = await find_in_tiger(conn, place, details)
     if row is not None:
         result = nres.create_from_tiger_row(row)
+        log().var_dump('Result', result)
         await nres.add_result_details(conn, result, details)
         return result
 
diff --git a/nominatim/api/results.py b/nominatim/api/results.py
index 63c9cf12..23cb47f4 100644
--- a/nominatim/api/results.py
+++ b/nominatim/api/results.py
@@ -21,6 +21,7 @@ import sqlalchemy as sa
 from nominatim.typing import SaSelect, SaRow
 from nominatim.api.types import Point, LookupDetails
 from nominatim.api.connection import SearchConnection
+from nominatim.api.logging import log
 
 # This file defines complex result data classes.
 # pylint: disable=too-many-instance-attributes
@@ -228,13 +229,18 @@ async def add_result_details(conn: SearchConnection, result: SearchResult,
     """ Retrieve more details from the database according to the
         parameters specified in 'details'.
     """
+    log().section('Query details for result')
     if details.address_details:
+        log().comment('Query address details')
         await complete_address_details(conn, result)
     if details.linked_places:
+        log().comment('Query linked places')
         await complete_linked_places(conn, result)
     if details.parented_places:
+        log().comment('Query parent places')
         await complete_parented_places(conn, result)
     if details.keywords:
+        log().comment('Query keywords')
         await complete_keywords(conn, result)
 
 
diff --git a/nominatim/api/v1/server_glue.py b/nominatim/api/v1/server_glue.py
index 8aa28cfe..35028526 100644
--- a/nominatim/api/v1/server_glue.py
+++ b/nominatim/api/v1/server_glue.py
@@ -13,12 +13,14 @@ import abc
 
 from nominatim.config import Configuration
 import nominatim.api as napi
+import nominatim.api.logging as loglib
 from nominatim.api.v1.format import dispatch as formatting
 
 CONTENT_TYPE = {
   'text': 'text/plain; charset=utf-8',
   'xml': 'text/xml; charset=utf-8',
-  'jsonp': 'application/javascript'
+  'jsonp': 'application/javascript',
+  'debug': 'text/html; charset=utf-8'
 }
 
 
@@ -131,6 +133,18 @@ class ASGIAdaptor(abc.ABC):
                or self.config().DEFAULT_LANGUAGE
 
 
+    def setup_debugging(self) -> bool:
+        """ Set up collection of debug information if requested.
+
+            Return True when debugging was requested.
+        """
+        if self.get_bool('debug', False):
+            loglib.set_log_output('html')
+            return True
+
+        return False
+
+
 def parse_format(params: ASGIAdaptor, result_type: Type[Any], default: str) -> str:
     """ Get and check the 'format' parameter and prepare the formatter.
         `fmtter` is a formatter and `default` the
@@ -175,6 +189,8 @@ async def details_endpoint(api: napi.NominatimAPIAsync, params: ASGIAdaptor) ->
             raise params.error("Missing ID parameter 'place_id' or 'osmtype'.")
         place = napi.OsmID(osmtype, params.get_int('osmid'), params.get('class'))
 
+    debug = params.setup_debugging()
+
     details = napi.LookupDetails(address_details=params.get_bool('addressdetails', False),
                                  linked_places=params.get_bool('linkedplaces', False),
                                  parented_places=params.get_bool('hierarchy', False),
@@ -184,10 +200,12 @@ async def details_endpoint(api: napi.NominatimAPIAsync, params: ASGIAdaptor) ->
         details.geometry_output = napi.GeometryFormat.GEOJSON
 
     locales = napi.Locales.from_accept_languages(params.get_accepted_languages())
-    print(locales.languages)
 
     result = await api.lookup(place, details)
 
+    if debug:
+        return params.build_response(loglib.get_and_disable(), 'debug')
+
     if result is None:
         raise params.error('No place with that OSM ID found.', status=404)
 
-- 
2.39.5