Hugh's LOG

오픈텔레메트리의 이해

AKA.DM — Fri, 4 Apr 2025 06:56:47 +0900

오픈텔레메트리란?

애플리케이션 관측성을 높이기 위한 오픈 소스 프레임워크

트레이스, 메트릭, 로그를 수집

트레이스?

분산 시스템에서 요청(Requset)의 흐름을 추적하는 데이터

- 특정 요청이 여러 서비스와 인프라를 거치면서 어떻게 처리되는지 분석

- 구성요소 : 트레이스ID, 스펜ID, 스펜

1. 트레이스ID : 하나의 요청을 식별하는 고유 ID

2. 스펜ID : 특정 작업(span)을 식별하는 고유 ID

3. 스펜(span) : 특정 작업을 식별하는 ID

트레이스ID vs SPANID

- 트레이스 ID : 하나의 요청이 여러 서비스를 걸쳐 실행될때 하나의 트레이스 아이디를 사용함

- 스팬 ID : 하나의 트레이스ID에 여러 스팬이 존재함

Trace ID: 4bf92f3577b34da6a3ce929d0e0e4736
├── Span ID (Root): 00f067aa0ba902b7 (API Gateway)
    ├── Span ID: a3c19a2b3f0d4c1e (User Service)
    ├── Span ID: f87c65a0bcdb4d5e (Order Service)
        ├── Span ID: 9df2c7d31abc0123 (Payment Service)

정리

	트레이스ID	스펜ID
역할	하나의 요청(Trace) 전체 식별	개별 작업(Span) 식별
길이	16바이트 (128비트)	8바이트 (64비트)
범위	트랜잭션 전체에 걸쳐 공유됨	특정 작업(Span) 내에서만 사용됨
관계	트레이스 내 모든 스팬이 같은 트레이스 ID를 공유	각 스팬은 고유한 스팬 ID를 가짐

메트릭?

시간 기반 데이터이며, 특정 시점에 측정된 값을 저장

정량적 표현이며, cpu 사용량, 요청수, 응답수 같은 정보를 저장

- 구성요소

1. 메트릭 이름 : 측정하는 값의 이름 http_request_total 등

2. 값 : 메트릭의 수치 95% cpu사용율 10ms 응답시간 등

3. 레이블/태그 : 메트릭을 세부적으로 구분하는 키-값 데이터 {method="GET", status="200"} 등

4. 타임스탬프 : 해당 메트릭이 수집된 시간

- 메트릭의종류

메트릭 종류	설명	예제
Counter (카운터)	증가만 가능 (Reset 전까지 감소 X)	http_requests_total (총 HTTP 요청 수)
UpDownCounter (업다운 카운터)	증가 & 감소 가능	active_users (현재 접속자 수)
Histogram (히스토그램)	값의 분포를 측정 (최소, 최대, 평균)	request_duration (응답 시간 분포)
Gauge (게이지)	특정 시점의 상태값	cpu_usage (현재 CPU 사용량)

로그?

이벤트 발생 기록을 남기는 데이터로 디버깅, 감사, 이벤트 분석 등에 사용

- 구성 요소

1. 타임스탬프 : 로그발생시

2. 레벨 : 로그 심각도(info, warn 등)

3. 메시지 : 다양한 이벤트 설명

최종정리

유형	목적	주요정보	예제
트레이스	요청의 흐름을 추적	트레이스아이디, 스펜아이디	api호출 시간 측정
메트릭	성능 모니터링	카운터, 게이지, 히스토그램, 업다운카운터	cpu사용률75%
로그	이벤트 기록	타임스탬프, 레벨, 메시지	db연결 실패 로그

String Formatting With String.Format Method in Python

AKA.DM — Mon, 21 Oct 2024 07:28:10 +0900

Another way to format strings is the string.format method.

This method indicates the places we want to change on a sting with curly braces.

For example, there is a variable named Linkedin below, and two sections are left blank with curly braces.

We pill place values in these sections wiht the string.format method. So how do we do it?

We write the variable we want to format. Then we call the format method by putting a period.

We write whatever we want to appear in the blank spaces in the method parenthesis.

For example, there are two print functions below. Formatting was done according to its values and the string expression we wanted to come as output.

Values in format brackets have idex numbers.

We can put these index numbers in curyl braces in the string so that the output is as we want.

For example, below, the values in the format brackets were mixed.

In order for the output to be as we want, we wrote the index numbers of the values in the parentheses in the curly brackets in the order we want.

As a result, we got the output in the order we wanted.

In the String.format method, the variable name can also be enclosed in the format brackets.

String Formatting With String.Format Method in Python

AKA.DM — Wed, 16 Oct 2024 07:45:12 +0900

Another way to format strings is the string.format method.

This method indicates the places we want to change on a string with curly braces.

For example, there is a variable named Linkedin below, and two sections are left blank with curly braces.

We will place values in these sections with the string.format method. So how we do it?

We write the variable we want to format. Then we call the format method by putting a period.

We write whatever we want to appear in the blank spaces in the method parenthesis.

For example, there are two print functions below. Formatting was done according to its values and the string expression we wanted to come as output.

Values in format brackets have index numbers.

We can put these index numbers in curly braces in the string so that the output is as we want.

For example, below, the values in the format brackets were mixed.

In order for the output to be as we want, we worte the index numbers of the vlaues in the parenthese in the curly brackets in the order we want.

As a result, we got the ouput in the order we wanted.

In the stirng.format method, the variable name can also be enclosed in the format brakets.

String Formatting With % Operator in Python

AKA.DM — Tue, 15 Oct 2024 07:40:15 +0900

The format is a method that helps us insert a variable or value anywhere in a string expression.

We can format using the percent sign.

For example, there is a sentence below. We would like to leave the blank in this sentence anonymous.

In other words, we do not want this empty part to remain costant ; we want to fill it with the vlaue we want in the next step.

So how do we do this?

If we want to see a string value anonymously anywhere in a string expression, we need to use %s in the first step.

The letter "S" is the first letter of the string.

We put %s in the section below that we will fill with the value we want.

Now let's examine how we can place the value we want in this section.

There are two print statements in the image below.

We wnat to put the word "teachers" in the first blank and the word "chidren" in other.

To do this, we first call the variable. Then we use the percent sign and finally write expresison after the percent sign.

So that the blank part can be filled with a different value each time.

If we wnated to use a integer value anonymously anywhere in a string expression, we need to use %d in the first step.

The letter "d" is the first letter of the "digit".

If we wnated to use a flaot value anonymously anywhere in a string expression, we need to use %f in the first step.

The letter "f" is the first letter of the "flaot".

While formatting float values, we can determine how many digits the decimal number will be.

We write the number of digits we want by putting a period next to the percent sign.

If we wnat to the dicimal part to consist of 3 digits by saying %.3f below.

We can perform formatting using percentage operator together.

In % formatting, we can operate using the values we set in the value.

String Formatting with Arithmetic Operations in Python

AKA.DM — Fri, 11 Oct 2024 07:52:44 +0900

We have learned in our previous lessons that we can perform arithmetic operations on string values.

However, we should not have thought of these arithmetic operations mathematically.

For example, aggregation was used to concatenate string values.

You can also do this collection as follows:

You can perform your operations from a shortcut by using the arithmetic operator before "equals".

You can perform the multipication operation in strings by using the mutiplication operator.

Again, as a shortcut, you can reach your goal by saying "arithmetic operator, equals" as below.

Complex Indexing and Slicing Operations in Python

AKA.DM — Thu, 10 Oct 2024 07:52:19 +0900

Strings have negative indexing as well as positive indexing.

Positive indexing starts from the first character of the string value and the first index number is zero. We know this.

In negative indexing, it starts from the last value and progresses to the beginning.

Index numbers starts from -1 in negative indexing.

We can index according to these index numbers :

Indexing using negative index nunbers is the same as the logic of positive indexing.

Indexing is done using square brackets.

For example, we called the "-3" index to reach the letter "a" of the value in the car variable below.

Slicing using negative index numbers is the same as positive slicing logic.

Slicing is done using square brackets.

Likewise, start, stop, and end parameters are used.

[Start : Stop : Step]

For example, below, we wanted to slice the "rra" seciton from the "Ferrari" value.

We set it as the start paramteres since the letter "R" is in the -5th idex.

Then, since we wanted the letter "a", we set the stop paramter up to the letter "r". So we set it to -2. If ytou remember, stop value was not included in slicing. It would be up to the stop value.

We left the stop parameter as default because the number of steps is one.

Addtion

Values[::-1] utilizes slicing with a step of -1, which essentially reserves the strings.

Indexing and Slicing in Strings in Python

AKA.DM — Wed, 2 Oct 2024 07:29:56 +0900

In Python, the process of accessing values, characters, etc. in a data type is called indexing.

Square brackets are used while indexing.

And the index number of the value we want to reach is written in square brackets.

For example, we want to reach teh first character of the value in the variable car below.

Since insdex number starts from zero in Python, we wrote zero in square brackets.

The process of reaching values, characters, etc. in a data type in Python is called sclicing.

Slicing is done using square brackets just like indexing.

We can enter three values inside square just like indexing.

These are Start for the start value, Stop for the end value and step values to determine the number of steps.

A colon is placed between these three values.

The stop value we worte in paraentheses is not included in the index. It will return characters up to the stop value

[Start : Stop : Step]

For example, we wanted it to return the values from the 1st index to the 5th index from the car variable below.

We did not write it in square brackets as the number of steps is one by default.

Let's work by determining the number of steps.

For example, below, we wanted to get the values starting from the 1st index to the 5th index in the variable car by going in 3 steps.

The character in the 1st index is the letter "e", so Python ouput it. The it took thres steps and got the letter "a".

Then it ended slicing because we said up to the 5th index.

If we do not write a stop value, Python will slice up to the last value in the variable after the value we set as the start.

For example, since the start parameter is three, below, it started from the 3rd index and output all the values until the end.

Python proceeds up to the stop value and slices if we do not write a start value.

For example, becuase the stop paramete is three, below, it ouputs the values up to the 3rd index.

Methods in String in Python-3

AKA.DM — Thu, 26 Sep 2024 07:41:37 +0900

The title() method converts only the first letter of the words in a string expression to uppercase

The strip() method in used to trim the values we want from the beginning and end of string values.

If we don't write anything inside the method, by default it removes all spaces to the left and right.

The strip() method can take a value in it. Trims all of this value at the begining and end of the string expression.

The rstirp() method is a variable is a variation of the strip method. It is called in an abbreviation for right strip.

Approximates the right side of the string expression. By default, it removes all spaces to the right.

The rstrip() method can contains values. It approaches the string expression from the right accroding to the value it receives and removes the entire value from the string expresison.

The lstrip() method is a variation of the strip method. It is called and abbreviation of the pharse left strip.

It approaches the string expression from the left accroding to the value it recieves and removes the entire value from the string expression

By using the dir() function, you can sell all the methods you can applyy to the data types in Python.

For example, the "space" variable contains a string expression below. If we wirte this variable inside the dir function, we can see all the methods we can apply on the strings.

Methods in Strings in Python 2

AKA.DM — Wed, 25 Sep 2024 07:28:39 +0900

Replace method is used to replace characters in string values.

It takes two values in it. The first is the value we want to change, and the other is new value.

For example, we wanted to get rid of the hypens between the letters of the name "joseph" below. And we did this request with the replace method.

In the Replace method, we can determine the number of changes we wnat to make on the string.

For example, we want to change the first 3 of the "/" characters of the object in the university variable below.

if we specify this number as the last value in Replace, we will get the result we want.

The swapcase() method converts uppercase letters in a sting value to lowercase letters and lowercase letters to uppercase characters.

The capitalize() method caplitalizes only the initial letter of a sring value.

The Upper method capitalizes all letters in string expression.

The Lower method makes all letters in the string lowercase.

The methods can be applied one after the other.

For example, we first capitalized only the first letter with the capitalize() method. Then we converted uppercase letters to lowercase and lowercase letters to uppercase characters with the swapcase() method.

Methods in Strings in Python

AKA.DM — Tue, 24 Sep 2024 07:35:31 +0900

Methods are various functions implemented on data structures. The first method we will learn in this context is the len method.

The Len method is called the abbreviation of the word lenght. It gives the length information of the objects we will put in it.

Spcae in strings are counted as characters.

Startwith() method takes a value in it. And based on the value it receives, it asks Python the following question : "Does the string start with the specified value?" It returns True if the answer is true and False if fales.

For example, there is a variable named web adress below. It contains the phrase "www.datasience.com".

We ask the following question to the variable with the startwith() method "Does the web adress start with www?"

The output is True because the answer is correct.

Let's also try to output as "false": Does the web address start with com?

The output is False because the anwer is incorrect .

In Python, the vlaues of an object are reached by its index number.

Index numbers start from zeor and continue increasing.

For example, the dot character below is in the 3rd index. Again, the "t" character is in the 6th index.

Startswith method can also include start and end index.

We can search accroding to these indexes and ask question to Python.

For example, we ask below : Does the value between the 4th and 9th index of the "web adress" variable begin wiht the word "data"?

Note : The value we wirte to the ending index is not inclueded.

In the example it will be up to the 8th index. 8 not included.

The endswith() method is very similar to the startswith() method.

And based on the value it receives, it asks Python the following question : "Does the stirng end with the specified value?"
It returns True if the answer is correct, and False if incorrect.

We got the output True because it was correct.

As in the startswith() method, we can enter the start and end parameters in the endswith() method.

For example, we aske below : Does the value in the variable end as "cial" between the 3rd and 10th indexes?

Note : The parameter we write to the ending is not included. We said up to ten below. Ten not inclueded.