From b00dfd3965f400956c5bb5b388e9d54ef98052e5 Mon Sep 17 00:00:00 2001
From: Matt Holt <mholt@users.noreply.github.com>
Date: Mon, 28 Oct 2019 14:39:37 -0600
Subject: v2: Logging! (#2831)

* logging: Initial implementation

* logging: More encoder formats, better defaults

* logging: Fix repetition bug with FilterEncoder; add more presets

* logging: DiscardWriter; delete or no-op logs that discard their output

* logging: Add http.handlers.log module; enhance Replacer methods

The Replacer interface has new methods to customize how to handle empty
or unrecognized placeholders. Closes #2815.

* logging: Overhaul HTTP logging, fix bugs, improve filtering, etc.

* logging: General cleanup, begin transitioning to using new loggers

* Fixes after merge conflict
---
 modules/logging/filters.go | 94 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 modules/logging/filters.go

(limited to 'modules/logging/filters.go')

diff --git a/modules/logging/filters.go b/modules/logging/filters.go
new file mode 100644
index 0000000..b44e084
--- /dev/null
+++ b/modules/logging/filters.go
@@ -0,0 +1,94 @@
+// Copyright 2015 Matthew Holt and The Caddy Authors
+//
+// Licensed 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.
+
+package logging
+
+import (
+	"net"
+
+	"github.com/caddyserver/caddy/v2"
+	"go.uber.org/zap/zapcore"
+)
+
+func init() {
+	caddy.RegisterModule(DeleteFilter{})
+	caddy.RegisterModule(IPMaskFilter{})
+}
+
+// LogFieldFilter can filter (or manipulate)
+// a field in a log entry. If delete is true,
+// out will be ignored and the field will be
+// removed from the output.
+type LogFieldFilter interface {
+	Filter(zapcore.Field) zapcore.Field
+}
+
+// DeleteFilter is a Caddy log field filter that
+// deletes the field.
+type DeleteFilter struct{}
+
+// CaddyModule returns the Caddy module information.
+func (DeleteFilter) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		Name: "caddy.logging.encoders.filter.delete",
+		New:  func() caddy.Module { return new(DeleteFilter) },
+	}
+}
+
+// Filter filters the input field.
+func (DeleteFilter) Filter(in zapcore.Field) zapcore.Field {
+	in.Type = zapcore.SkipType
+	return in
+}
+
+// IPMaskFilter is a Caddy log field filter that
+// masks IP addresses.
+type IPMaskFilter struct {
+	IPv4CIDR int `json:"ipv4_cidr,omitempty"`
+	IPv6CIDR int `json:"ipv6_cidr,omitempty"`
+}
+
+// CaddyModule returns the Caddy module information.
+func (IPMaskFilter) CaddyModule() caddy.ModuleInfo {
+	return caddy.ModuleInfo{
+		Name: "caddy.logging.encoders.filter.ip_mask",
+		New:  func() caddy.Module { return new(IPMaskFilter) },
+	}
+}
+
+// Filter filters the input field.
+func (m IPMaskFilter) Filter(in zapcore.Field) zapcore.Field {
+	host, port, err := net.SplitHostPort(in.String)
+	if err != nil {
+		host = in.String // assume whole thing was IP address
+	}
+	ipAddr := net.ParseIP(host)
+	if ipAddr == nil {
+		return in
+	}
+	bitLen := 32
+	cidrPrefix := m.IPv4CIDR
+	if ipAddr.To16() != nil {
+		bitLen = 128
+		cidrPrefix = m.IPv6CIDR
+	}
+	mask := net.CIDRMask(cidrPrefix, bitLen)
+	masked := ipAddr.Mask(mask)
+	if port == "" {
+		in.String = masked.String()
+	} else {
+		in.String = net.JoinHostPort(masked.String(), port)
+	}
+	return in
+}
-- 
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