VSCodeのdevcontainerにtesseract5系を導入する方法

# 目標
VSCodeのdevcontainerにTesseractの5系をインストールする

# 本題

## 用意するファイル

用意するファイルは下記のみ
devcontainerで自動追加されるファイルのみ

```bash:ファイル一覧
$ tree -a
.
└── .devcontainer
    ├── Dockerfile
    └── devcontainer.json
```

Dockerfile内でTesseractのインストールを行う

```Dockerfile:Dockerfile
# See here for image contents: https://github.com/microsoft/vscode-dev-containers/tree/v0.205.1/containers/python-3/.devcontainer/base.Dockerfile

# [Choice] Python version (use -bullseye variants on local arm64/Apple Silicon): 3, 3.10, 3.9, 3.8, 3.7, 3.6, 3-bullseye, 3.10-bullseye, 3.9-bullseye, 3.8-bullseye, 3.7-bullseye, 3.6-bullseye, 3-buster, 3.10-buster, 3.9-buster, 3.8-buster, 3.7-buster, 3.6-buster
ARG VARIANT="3.10-bullseye"
FROM mcr.microsoft.com/vscode/devcontainers/python:0-${VARIANT}

# [Choice] Node.js version: none, lts/*, 16, 14, 12, 10
ARG NODE_VERSION="none"
RUN if [ "${NODE_VERSION}" != "none" ]; then su vscode -c "umask 0002 && . /usr/local/share/nvm/nvm.sh && nvm install ${NODE_VERSION} 2>&1"; fi

# [Optional] If your pip requirements rarely change, uncomment this section to add them to the image.
COPY requirements.txt /tmp/pip-tmp/
RUN pip3 --disable-pip-version-check --no-cache-dir install -r /tmp/pip-tmp/requirements.txt \
   && rm -rf /tmp/pip-tmp

# [Optional] Uncomment this section to install additional OS packages.
RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
    && apt-get -y install --no-install-recommends apt-transport-https libtesseract-dev\
    && echo "deb https://notesalexp.org/tesseract-ocr5/$(lsb_release -cs)/ $(lsb_release -cs) main" | tee /etc/apt/sources.list.d/notesalexp.list \
    && wget -O - https://notesalexp.org/debian/alexp_key.asc | sudo apt-key add -

RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
    && apt-get -y install --no-install-recommends tesseract-ocr tesseract-ocr-jpn

# [Optional] Uncomment this line to install global node packages.
# RUN su vscode -c "source /usr/local/share/nvm/nvm.sh && npm install -g <your-package-here>" 2>&1
```

デフォルトから変更なし

```json:devcontainer.json
// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
// https://github.com/microsoft/vscode-dev-containers/tree/v0.205.1/containers/python-3
{
	"name": "Python 3",
	"build": {
		"dockerfile": "Dockerfile",
		"context": "..",
		"args": { 
			// Update 'VARIANT' to pick a Python version: 3, 3.10, 3.9, 3.8, 3.7, 3.6
			// Append -bullseye or -buster to pin to an OS version.
			// Use -bullseye variants on local on arm64/Apple Silicon.
			"VARIANT": "3.8",
			// Options
			"NODE_VERSION": "none"
		}
	},

	// Set *default* container specific settings.json values on container create.
	"settings": { 
		"python.defaultInterpreterPath": "/usr/local/bin/python",
		"python.linting.enabled": true,
		"python.linting.pylintEnabled": true,
		"python.formatting.autopep8Path": "/usr/local/py-utils/bin/autopep8",
		"python.formatting.blackPath": "/usr/local/py-utils/bin/black",
		"python.formatting.yapfPath": "/usr/local/py-utils/bin/yapf",
		"python.linting.banditPath": "/usr/local/py-utils/bin/bandit",
		"python.linting.flake8Path": "/usr/local/py-utils/bin/flake8",
		"python.linting.mypyPath": "/usr/local/py-utils/bin/mypy",
		"python.linting.pycodestylePath": "/usr/local/py-utils/bin/pycodestyle",
		"python.linting.pydocstylePath": "/usr/local/py-utils/bin/pydocstyle",
		"python.linting.pylintPath": "/usr/local/py-utils/bin/pylint"
	},

	// Add the IDs of extensions you want installed when the container is created.
	"extensions": [
		"ms-python.python",
		"ms-python.vscode-pylance"
	],

	// Use 'forwardPorts' to make a list of ports inside the container available locally.
	// "forwardPorts": [],

	// Use 'postCreateCommand' to run commands after the container is created.
	// "postCreateCommand": "pip3 install --user -r requirements.txt",

	// Comment out connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
	"remoteUser": "vscode"
}

```

コンテナを立ち上げれば完了

```bash
$ tesseract --version
tesseract 5.1.0
 leptonica-1.76.0
  libgif 5.1.4 : libjpeg 6b (libjpeg-turbo 1.5.2) : libpng 1.6.36 : libtiff 4.1.0 : zlib 1.2.11 : libwebp 0.6.1 : libopenjp2 2.3.0
 Found AVX2
 Found AVX
 Found FMA
 Found SSE4.1
 Found OpenMP 201511
 Found libarchive 3.3.3 zlib/1.2.11 liblzma/5.2.4 bz2lib/1.0.6 liblz4/1.8.3 libzstd/1.3.8
 Found libcurl/7.64.0 OpenSSL/1.1.1d zlib/1.2.11 libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.5) libssh2/1.8.0 nghttp2/1.36.0 librtmp/2.3
```

## 詰まったところ
devcontainerのOSがubuntuだと勘違いしていて時間を溶かした  
自分の環境と検索結果の環境を比べるの大切ですね


## 参考
- https://techviewleo.com/install-and-use-tesseract-ocr-on-debian/