skywalking/plugins/sw_flask.py

#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

from skywalking import Layer, Component, config
from skywalking.trace import tags
from skywalking.trace.carrier import Carrier
from skywalking.trace.context import get_context
from skywalking.trace.span import NoopSpan
from skywalking.trace.tags import Tag


def install():
    from flask import Flask
    _full_dispatch_request = Flask.full_dispatch_request
    _handle_user_exception = Flask.handle_user_exception
    _handle_exception = Flask.handle_exception

    def params_tostring(params):
        return "\n".join([k + '=[' + ",".join(params.getlist(k)) + ']' for k, _ in params.items()])

    def _sw_full_dispatch_request(this: Flask):
        import flask
        req = flask.request
        context = get_context()
        carrier = Carrier()

        for item in carrier:
            if item.key.capitalize() in req.headers:
                item.val = req.headers[item.key.capitalize()]
        with context.new_entry_span(op=req.path, carrier=carrier) as span:
            span.layer = Layer.Http
            span.component = Component.Flask
            span.peer = '%s:%s' % (req.environ["REMOTE_ADDR"], req.environ["REMOTE_PORT"])
            span.tag(Tag(key=tags.HttpMethod, val=req.method))
            span.tag(Tag(key=tags.HttpUrl, val=req.url.split("?")[0]))
            if config.flask_collect_http_params and req.values:
                span.tag(Tag(key=tags.HttpParams,
                             val=params_tostring(req.values)[0:config.http_params_length_threshold]))
            resp = _full_dispatch_request(this)

            if resp.status_code >= 400:
                span.error_occurred = True

            span.tag(Tag(key=tags.HttpStatus, val=resp.status_code, overridable=True))
            return resp

    def _sw_handle_user_exception(this: Flask, e):
        if e is not None:
            entry_span = get_context().active_span()
            if entry_span is not None and type(entry_span) is not NoopSpan:
                entry_span.raised()

        return _handle_user_exception(this, e)

    def _sw_handle_exception(this: Flask, e):
        if e is not None:
            entry_span = get_context().active_span()
            if entry_span is not None and type(entry_span) is not NoopSpan:
                entry_span.raised()

        return _handle_exception(this, e)

    Flask.full_dispatch_request = _sw_full_dispatch_request
    Flask.handle_user_exception = _sw_handle_user_exception
    Flask.handle_exception = _sw_handle_exception