+# 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>"
projects / nominatim.git / commitdiff