zio.logging.internal.LogAppender.scala Maven / Gradle / Ivy
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/*
* Copyright 2019-2024 John A. De Goes and the ZIO Contributors
*
* 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 zio.logging.internal
import zio._
import scala.collection.mutable
/**
* A [[LogAppender]] is a low-level interface designed to be the bridge between
* ZIO Logging and logging backends, such as Logback. This interface is slightly
* higher-level than a string builder, because it allows for structured logging,
* and preserves all ZIO-specific information about runtime failures.
*/
private[logging] trait LogAppender { self =>
/**
* Appends a [[zio.Cause]] to the log. Some logging backends may have
* special support for logging failures.
*/
def appendCause(cause: Cause[Any]): Unit
/**
* Appends a numeric value to the log.
*/
def appendNumeric[A](numeric: A): Unit
/**
* Appends unstructured text to the log.
*/
def appendText(text: String): Unit
/**
* Appends a key/value string pair to the log.
*/
def appendKeyValue(key: String, value: String): Unit = appendKeyValue(key, _.appendText(value))
/**
* Appends a key/value pair, with the value it created with the log appender.
*/
def appendKeyValue(key: String, appendValue: LogAppender => Unit): Unit = {
openKey()
try appendText(key)
finally closeKeyOpenValue()
try appendValue(self)
finally closeValue()
}
def appendKeyValueSeparator(): Unit = ()
def appendKeyValues(keyValues: Iterable[(String, String)]): Unit = {
val iterator = keyValues.iterator
while (iterator.hasNext) {
val (key, value) = iterator.next()
appendKeyValue(key, value)
if (iterator.hasNext) {
appendKeyValueSeparator()
}
}
}
/**
* Marks the close of a key for a key/value pair, and the opening of the value.
*/
def closeKeyOpenValue(): Unit
/**
* Marks the close of the log entry
*/
def closeLogEntry(): Unit
/**
* Marks the close of the value of a key/value pair.
*/
def closeValue(): Unit
/**
* Marks the open of the key.
*/
def openKey(): Unit
/**
* Marks the start of the log entry
*/
def openLogEntry(): Unit
/**
* Modifies the way text is appended to the log.
*/
final def withAppendText(f: (String => Unit) => (String => Unit)): LogAppender = new LogAppender.Proxy(self) {
val decorated: String => Unit = f(self.appendText(_))
override def appendText(text: String): Unit = decorated(text)
}
}
private[logging] object LogAppender {
class Proxy(self: LogAppender) extends LogAppender {
override def appendCause(cause: Cause[Any]): Unit = self.appendCause(cause)
override def appendKeyValueSeparator(): Unit = self.appendKeyValueSeparator()
override def appendNumeric[A](numeric: A): Unit = self.appendNumeric(numeric)
override def appendText(text: String): Unit = self.appendText(text)
override def closeKeyOpenValue(): Unit = self.closeKeyOpenValue()
override def closeLogEntry(): Unit = self.closeLogEntry()
override def closeValue(): Unit = self.closeValue()
override def openKey(): Unit = self.openKey()
override def openLogEntry(): Unit = self.openLogEntry()
}
/**
* A [[LogAppender]] for unstructured logging, which simply turns everything
* into text, and passes it to the given text appender function.
*/
def unstructured(textAppender: String => Any): LogAppender = new LogAppender { self =>
override def appendCause(cause: Cause[Any]): Unit = appendText(cause.prettyPrint)
override def appendKeyValueSeparator(): Unit = appendText(" ")
override def appendNumeric[A](numeric: A): Unit = appendText(numeric.toString)
override def appendText(text: String): Unit = { textAppender(text); () }
override def closeKeyOpenValue(): Unit = appendText("=")
override def closeLogEntry(): Unit = ()
override def closeValue(): Unit = ()
override def openKey(): Unit = ()
override def openLogEntry(): Unit = ()
}
def json(textAppender: String => Any): LogAppender = new LogAppender { self =>
val AnsiColorRegex = "\\u001b\\[\\d+m".r
class State(
var root: Boolean = false,
var separateKeyValue: Boolean = false,
var writingKey: Boolean = false,
val content: mutable.StringBuilder = new mutable.StringBuilder,
var textContentIsJson: Boolean = false,
var textContent: mutable.StringBuilder = new mutable.StringBuilder,
var quoteTextContent: Boolean = false
) {
def appendContent(str: CharSequence): Unit = { content.append(str); () }
def appendTextContent(str: CharSequence, quote: Boolean): Unit = {
quoteTextContent |= quote
textContent.append(str)
()
}
}
val stack = new mutable.Stack[State]()
def current: State = stack.top
override def appendCause(cause: Cause[Any]): Unit = appendText(cause.prettyPrint)
override def appendNumeric[A](numeric: A): Unit =
if (current.writingKey) current.appendContent(numeric.toString)
else current.appendTextContent(numeric.toString, false)
override def appendText(text: String): Unit = {
current.textContentIsJson = JsonValidator.isJson(text)
if (current.writingKey) current.appendContent(text)
else current.appendTextContent(text, !current.textContentIsJson)
}
def beginStructure(root: Boolean = false): Unit = { stack.push(new State(root = root)); () }
def endStructure(): CharSequence = {
val result = new mutable.StringBuilder
val cleanedTextContent = {
// Do a little cleanup to handle default log formats (quoted, colored and spaced)
if (current.textContent.startsWith("\"") && current.textContent.endsWith("\""))
current.textContent = current.textContent.drop(1).dropRight(1)
if (AnsiColorRegex.findFirstMatchIn(current.textContent).nonEmpty) {
val cleaned = AnsiColorRegex.replaceAllIn(current.textContent, "")
current.textContent.clear()
current.textContent.appendAll(cleaned)
}
if (current.textContent.forall(_ == ' ')) current.textContent.clear()
current.textContent.toString()
}
if (current.content.isEmpty && !current.root) {
// Simple value
if (current.quoteTextContent) result.append("\"")
result.append(escapeTextContent(cleanedTextContent))
if (current.quoteTextContent) result.append("\"")
} else {
// Structure
result.append("{")
if (current.textContent.nonEmpty) {
result.append(""""text_content":""")
if (current.quoteTextContent) result.append("\"")
result.append(escapeTextContent(cleanedTextContent))
if (current.quoteTextContent) result.append("\"")
}
if (current.content.nonEmpty) {
if (current.textContent.nonEmpty) result.append(",")
result.append(current.content)
}
result.append("}")
}
if (result.isEmpty) {
result.append("null")
}
stack.pop()
result
}
override def closeKeyOpenValue(): Unit = {
current.writingKey = false
current.appendContent("""":""")
beginStructure()
}
override def closeLogEntry(): Unit = {
textAppender(endStructure().toString)
()
}
override def closeValue(): Unit = {
val result = endStructure()
current.appendContent(result)
}
override def openKey(): Unit = {
if (current.separateKeyValue) current.appendContent(",")
current.separateKeyValue = true
current.writingKey = true
current.appendContent("\"")
}
override def openLogEntry(): Unit = {
stack.clear()
beginStructure(true)
}
private def escapeTextContent(content: String): CharSequence =
if (current.textContentIsJson) content
else JsonEscape(content)
}
}
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