개요

이 항목에서는 OSS의 FaaS 서버인 "Fn Project"를 사용하여 Python의 함수를 이동하는 패턴을 다룹니다.

아래 그림과 같이 Python의 곱셈 함수를 Fn 서버에 배포하고 이동합니다.

가정 독자

Fn Project에서 Python 프로그램 아직 스스로 움직이지 않은 분

「Fn Project를 사용해 JavaScript로 쓴 function을 Node로 움직여 본다」의 파이썬 버전에 관심이 있다면

준비

Fn Project를 이동할 때까지는 다른 항목"OCI의 Micro Instance에서 CentOS에 Fn Project 서버를 설치해보십시오"을 참조하십시오.

이 항목에서 필자는 OCI의 Micro Instance에서 작업합니다.

파이썬으로 function 이동

작업의 기본 흐름은 Introduction to Fn with Python에 쓰여진 것을 따르고 있습니다.

Fn의 앱

또 다른 항목 「Fn Project를 사용해 JavaScript로 쓴 function을 Node로 움직여 본다」에서 fn create app에서 fn에 "calc-fn-app"앱을 만들고있는 것에 Function을 추가하는 형태를 취합니다.

등록

/multiply라는 위치에 Python으로 함수를 하나 만들기 위해 fn init를 실행합니다.

$ fn init --runtime python --trigger http multiply
Creating function at: ./multiply
Function boilerplate generated.
func.yaml created.

아래와 같은 세 개의 파일이 있습니다.

$ ls
func.py  func.yaml  requirements.txt

코드 변경

아래와 같이 입력값의 left와 right를 곱하여 반환하는 함수로 다시 씁니다.

import io
import json
from decimal import *

from fdk import response


def handler(ctx, data: io.BytesIO=None):
    value = Decimal('NaN')
    try:
        body = json.loads(data.getvalue())
        left = Decimal(body.get('left'))
        right = Decimal(body.get('right'))
        value = left * right
    except (Exception, ValueError) as ex:
        print(str(ex))

    return response.Response(
        ctx, response_data=json.dumps(
            {"result": str(value)}),
        headers={"Content-Type": "application/json"}
    )

앱 배포 -w로 작업 디렉토리를 지정하여 등록하고 있습니다.

fn --verbose deploy --app calc-fn-app --local -w /home/opc/calc-fn-app/multiply

첫회 실행시에는 다음과 같은 흐름이 되는 것 같습니다.

$ fn --verbose deploy --app calc-fn-app --local -w /home/opc/calc-fn-app/multiply
Deploying multiply to app: calc-fn-app
Bumped to version 0.0.2
Building image fndemouser/multiply:0.0.2
FN_REGISTRY:  fndemouser
Current Context:  default
Sending build context to Docker daemon  6.144kB
Step 1/12 : FROM fnproject/python:3.6-dev as build-stage
3.6-dev: Pulling from fnproject/python
80369df48736: Pull complete
aaba0609d543: Pull complete
a97b990f94a5: Pull complete
af4a941e5376: Pull complete
709c35256bb6: Pull complete
3c3deb8445b4: Pull complete
Digest: sha256:8ac8c28a68fd0442b9ddcdf6a41f30230482d72d1024cafca06c9f1ac0bd821c
Status: Downloaded newer image for fnproject/python:3.6-dev
 ---> c5dbe9a0175b
Step 2/12 : WORKDIR /function
 ---> Running in f7aaa0e58f7a
Removing intermediate container f7aaa0e58f7a
 ---> 697f68e69e7c
Step 3/12 : ADD requirements.txt /function/
 ---> c4472f73a275
Step 4/12 : RUN pip3 install --target /python/  --no-cache --no-cache-dir -r requirements.txt &&                         rm -fr ~/.cache/pip /tmp* requirements.txt func.yaml Dockerfile .venv
 ---> Running in 4f758b74080b
Collecting fdk
  Downloading https://files.pythonhosted.org/packages/1d/b8/41b81bf76766f7e810627728647a8076626070a6e1d01a18a8ed16bd3d3f/fdk-0.1.12-py3-none-any.whl (46kB)
Collecting iso8601==0.1.12
  Downloading https://files.pythonhosted.org/packages/ef/57/7162609dab394d38bbc7077b7ba0a6f10fb09d8b7701ea56fa1edc0c4345/iso8601-0.1.12-py2.py3-none-any.whl
Collecting httptools>=0.0.10
  Downloading https://files.pythonhosted.org/packages/1b/03/215969db11abe8741e9c266a4cbe803a372bd86dd35fa0084c4df6d4bd00/httptools-0.0.13.tar.gz (104kB)
Collecting pbr!=2.1.0,>=2.0.0
  Downloading https://files.pythonhosted.org/packages/7a/db/a968fd7beb9fe06901c1841cb25c9ccb666ca1b9a19b114d1bbedf1126fc/pbr-5.4.4-py2.py3-none-any.whl (110kB)
Collecting pytest==4.0.1
  Downloading https://files.pythonhosted.org/packages/81/27/d4302e4e00497448081120f65029696070806bc8e649b83f644de006d710/pytest-4.0.1-py2.py3-none-any.whl (217kB)
Collecting pytest-asyncio==0.9.0
  Downloading https://files.pythonhosted.org/packages/33/7f/2ed9f460872ebcc62d30afad167673ca10df36ff56a6f6df2f1d3671adc8/pytest_asyncio-0.9.0-py3-none-any.whl
Collecting py>=1.5.0
  Downloading https://files.pythonhosted.org/packages/99/8d/21e1767c009211a62a8e3067280bfce76e89c9f876180308515942304d2d/py-1.8.1-py2.py3-none-any.whl (83kB)
Collecting pluggy>=0.7
  Downloading https://files.pythonhosted.org/packages/a0/28/85c7aa31b80d150b772fbe4a229487bc6644da9ccb7e427dd8cc60cb8a62/pluggy-0.13.1-py2.py3-none-any.whl
Collecting attrs>=17.4.0
  Downloading https://files.pythonhosted.org/packages/a2/db/4313ab3be961f7a763066401fb77f7748373b6094076ae2bda2806988af6/attrs-19.3.0-py2.py3-none-any.whl
Collecting setuptools
  Downloading https://files.pythonhosted.org/packages/a7/c5/6c1acea1b4ea88b86b03280f3fde1efa04fefecd4e7d2af13e602661cde4/setuptools-45.1.0-py3-none-any.whl (583kB)
Collecting more-itertools>=4.0.0
  Downloading https://files.pythonhosted.org/packages/72/96/4297306cc270eef1e3461da034a3bebe7c84eff052326b130824e98fc3fb/more_itertools-8.2.0-py3-none-any.whl (43kB)
Collecting six>=1.10.0
  Downloading https://files.pythonhosted.org/packages/65/eb/1f97cb97bfc2390a276969c6fae16075da282f5058082d4cb10c6c5c1dba/six-1.14.0-py2.py3-none-any.whl
Collecting atomicwrites>=1.0
  Downloading https://files.pythonhosted.org/packages/52/90/6155aa926f43f2b2a22b01be7241be3bfd1ceaf7d0b3267213e8127d41f4/atomicwrites-1.3.0-py2.py3-none-any.whl
Collecting importlib-metadata>=0.12; python_version < "3.8"
  Downloading https://files.pythonhosted.org/packages/8b/03/a00d504808808912751e64ccf414be53c29cad620e3de2421135fcae3025/importlib_metadata-1.5.0-py2.py3-none-any.whl
Collecting zipp>=0.5
  Downloading https://files.pythonhosted.org/packages/be/69/4ac28bf238f287f1677f41392e24d2c4ffafcf11648c23824f5f62ef6ccb/zipp-2.1.0-py3-none-any.whl
Building wheels for collected packages: httptools
  Building wheel for httptools (setup.py): started
  Building wheel for httptools (setup.py): finished with status 'done'
  Created wheel for httptools: filename=httptools-0.0.13-cp36-cp36m-linux_x86_64.whl size=217310 sha256=51eb19168c0639662416a8ad83b9df7d7ceb8eb14a58ce3bec5ffe3ab3b07a7f
  Stored in directory: /tmp/pip-ephem-wheel-cache-pwxrmfa5/wheels/e8/3e/2e/013f99b42efc25cf3589730cf380738e46b1e5edaf2f78d525
Successfully built httptools
Installing collected packages: iso8601, httptools, pbr, py, zipp, importlib-metadata, pluggy, attrs, setuptools, more-itertools, six, atomicwrites, pytest, pytest-asyncio, fdk
Successfully installed atomicwrites-1.3.0 attrs-19.3.0 fdk-0.1.12 httptools-0.0.13 importlib-metadata-1.5.0 iso8601-0.1.12 more-itertools-8.2.0 pbr-5.4.4 pluggy-0.13.1 py-1.8.1 pytest-4.0.1 pytest-asyncio-0.9.0 setuptools-45.1.0 six-1.14.0 zipp-2.1.0
WARNING: You are using pip version 19.3.1; however, version 20.0.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Removing intermediate container 4f758b74080b
 ---> 5246c18d4e6f
Step 5/12 : ADD . /function/
 ---> c6181bb33bd1
Step 6/12 : RUN rm -fr /function/.pip_cache
 ---> Running in 695fe059e692
Removing intermediate container 695fe059e692
 ---> 5ea69eaafc3a
Step 7/12 : FROM fnproject/python:3.6
3.6: Pulling from fnproject/python
80369df48736: Already exists
aaba0609d543: Already exists
a97b990f94a5: Already exists
af4a941e5376: Already exists
709c35256bb6: Already exists
671870542c6c: Pull complete
936a6f40830a: Pull complete
Digest: sha256:3b438ba11405bba0f6e1e8d8819c9b8be38249da7253491f3cf9f7e5ed6c0ec6
Status: Downloaded newer image for fnproject/python:3.6
 ---> e8e10863d7cd
Step 8/12 : WORKDIR /function
 ---> Running in ddbc794f4bd9
Removing intermediate container ddbc794f4bd9
 ---> 4e3bed62a7f5
Step 9/12 : COPY --from=build-stage /python /python
 ---> b1c7d4fd7598
Step 10/12 : COPY --from=build-stage /function /function
 ---> 87446e069bd2
Step 11/12 : ENV PYTHONPATH=/function:/python
 ---> Running in af075fbcae2c
Removing intermediate container af075fbcae2c
 ---> 98a9f515e7e0
Step 12/12 : ENTRYPOINT ["/python/bin/fdk", "/function/func.py", "handler"]
 ---> Running in 555033ab1e55
Removing intermediate container 555033ab1e55
 ---> 9942a3d98858
Successfully built 9942a3d98858
Successfully tagged fndemouser/multiply:0.0.2

Updating function multiply using image fndemouser/multiply:0.0.2...
Successfully created function: multiply with fndemouser/multiply:0.0.2
Successfully created trigger: multiply
Trigger Endpoint: http://127.0.0.1:18080/t/calc-fn-app/multiply

fn 명령으로 확인합니다. (다른 엔트리로 plus, minus를 만들고 있습니다)

$ fn list fn calc-fn-app
NAME            IMAGE                           ID
multiply        fndemouser/multiply:0.0.2       01E086F2D6NG8G00GZJ000001E
plus            fndemouser/plus:0.0.2           01E0393FDCNG8G00GZJ000000E
subtract        fndemouser/subtract:0.0.3       01E05KAKGENG8G00GZJ0000013

Docker 명령으로 확인하면 해당 컨테이너의 이미지가 만들어졌음을 알 수 있습니다.

$ docker images | grep multiply
fndemouser/multiply   0.0.2               9942a3d98858        About a minute ago   175MB

실행

등록시의 말미에 있던 URL에 curl로 액세스 해 봅니다.

$ curl -d '{"left":"2", "right":"4"}' http://127.0.0.1:18080/t/calc-fn-app/multiply
{"result": "8"}

2*4의 결과인 8이 반환되고 있습니다.

결론

이 항목에서는 Fn project를 사용하여 Python에서 작성한 function을 움직이는 것을 다루었습니다.

이 항목에서 사용한 코드는 htps : // 기주 b. 이 m / hrkt / 또는 lc-f- p / re / s / g / 0.0.3 태그에 저장됩니다.

보충: 외부 라이브러리

이 항목에서는 외부 라이브러리를 사용하지 않았지만 requirements.txt에 나열되어 pip를 사용할 수 있습니다.

보충: 이 항목을 작성할 때

이 항목을 작성할 때 OCI의 마이크로 인스턴스에 다음과 같은 상황을 만들고 노트북에서 클라우드 측으로 ssh로 원격으로 연결하여 작업했습니다.

ssh 앞에 화면에서 여러 장의 창을 올려 놓고 작업하십시오

VS Code를 WEB로 움직여 "cdr / code-server와 OCI의 Always Free Micro 인스턴스에서 VS Code를 실행해보십시오."

Fn 프로젝트 서버도 거기에서 움직입니다

코드는 GitHub에