Add devcontainer with PostgreSQL and Liquibase (#1)

* Add Python devcontainer with Node & PostgreSQL

This is the [out of the box VS Code devcontainer that bundles Python,
Node and PostgreSQL][1].  The only amendment was to apply [the bug fix
for a bug with the docker compose volume][2], that prevented the
container from starting.

[1]: https://github.com/microsoft/vscode-dev-containers/tree/main/containers/python-3-postgres
[2]: microsoft/vscode-remote-release#5388 (comment)

* Add VS Code PostgreSQL extension on devcontainer

We use [the most popular VS Code PostgreSQL extension][3].

[3]: https://marketplace.visualstudio.com/items?itemName=ckolkman.vscode-postgres

* Install psql on devcontainer

[psql][4] is the command line client for PostgreSQL.

[4]: https://www.postgresql.org/docs/current/app-psql.html

* Add shellcheck extension on devcontainer

* Add Java to devcontainer (needed for Liquibase)

Java is installed on the devcontainer as a [devcontainer feature][5],
which makes the installation very easy.

[5]: https://containers.dev/features

* Install Liquibase on devcontainer

[Liquibase][6] is an open source tool for versioning database changes.

[6]: https://www.liquibase.org/

* Create transaction database table via liquibase

* Seed database with 3 initial transactions

* Add liquibase update script

* Add script to create database if it does not exist

See https://stackoverflow.com/a/18389184

* Create & populate database on devcontainer startup

Using the [devcontainer postcreate command][7] for this.

[7]: https://containers.dev/implementors/json_reference/#lifecycle-scripts

* Run Liquibase in headless mode

We run it in headless mode because we are invoking it from a script
which gets automatically invoked by the devcontainer as a [postcreate
command][8].

[8]: https://containers.dev/implementors/json_reference/#lifecycle-scripts

.devcontainer/Dockerfile

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+# [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-bullseye
+FROM mcr.microsoft.com/vscode/devcontainers/python:0-${VARIANT}
+
+ENV PYTHONUNBUFFERED 1
+
+# [Choice] Node.js version: none, lts/*, 16, 14, 12, 10
+ARG NODE_VERSION="none"
+RUN if [ "${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 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
+
+
+# Use the PostgreSQL apt repository to install Postgres command line tools (see https://www.postgresql.org/download/linux/debian/)
+# Create the file repository configuration:
+RUN sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list' \
+# Import the repository signing key:
+    && wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -
+
+# [Optional] Uncomment this section to install additional OS packages.
+ARG POSTGRES_VERSION="14"
+RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
+    && apt-get -y install --no-install-recommends postgresql-client-${POSTGRES_VERSION}
+
+# Install Liquibase
+ARG LIQUIBASE_VERSION=4.16.1
+ARG LIQUIBASE_DOWNLOAD_DIR=/tmp/liquibase
+ARG LIQUIBASE_INSTALL_DIR=/usr/local/bin/liquibase/
+RUN export LIQUIBASE_BUNDLE=liquibase-${LIQUIBASE_VERSION}.zip \
+    && mkdir -p ${LIQUIBASE_DOWNLOAD_DIR} \
+    && mkdir -p ${LIQUIBASE_INSTALL_DIR} \
+    && cd ${LIQUIBASE_DOWNLOAD_DIR} || exit \
+    && wget -q --show-progress https://github.com/liquibase/liquibase/releases/download/v${LIQUIBASE_VERSION}/${LIQUIBASE_BUNDLE} \
+    && unzip ${LIQUIBASE_BUNDLE} \
+    && cp -r ${LIQUIBASE_DOWNLOAD_DIR}/. ${LIQUIBASE_INSTALL_DIR} \
+    && chmod +x ${LIQUIBASE_INSTALL_DIR}liquibase \
+    && rm -rf ${LIQUIBASE_DOWNLOAD_DIR}

.devcontainer/devcontainer.json

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+// For format details, see https://aka.ms/devcontainer.json. For config options, see the README at:
+// https://github.com/microsoft/vscode-dev-containers/tree/v0.245.2/containers/python-3-postgres
+// Update the VARIANT arg in docker-compose.yml to pick a Python version
+{
+	"name": "Python 3 & PostgreSQL",
+	"dockerComposeFile": "docker-compose.yml",
+	"service": "app",
+	"workspaceFolder": "/workspaces/${localWorkspaceFolderBasename}",
+
+	// Configure tool-specific properties.
+	"customizations": {
+		// Configure properties specific to VS Code.
+		"vscode": {
+			// Set *default* container specific settings.json values on container create.
+			"settings": { 
+				"python.defaultInterpreterPath": "/usr/local/bin/python",
+				"python.linting.enabled": true,
+				"python.linting.pylintEnabled": true,
+				"python.formatting.autopep8Path": "/usr/local/py-utils/bin/autopep8",
+				"python.formatting.blackPath": "/usr/local/py-utils/bin/black",
+				"python.formatting.yapfPath": "/usr/local/py-utils/bin/yapf",
+				"python.linting.banditPath": "/usr/local/py-utils/bin/bandit",
+				"python.linting.flake8Path": "/usr/local/py-utils/bin/flake8",
+				"python.linting.mypyPath": "/usr/local/py-utils/bin/mypy",
+				"python.linting.pycodestylePath": "/usr/local/py-utils/bin/pycodestyle",
+				"python.linting.pydocstylePath": "/usr/local/py-utils/bin/pydocstyle",
+				"python.linting.pylintPath": "/usr/local/py-utils/bin/pylint",
+				"python.testing.pytestPath": "/usr/local/py-utils/bin/pytest"
+			},
+
+			// Add the IDs of extensions you want installed when the container is created.
+			"extensions": [
+				"ms-python.python",
+				"ms-python.vscode-pylance",
+				"ckolkman.vscode-postgres",
+				"timonwong.shellcheck"
+			]
+		}
+	},
+
+	"remoteEnv": {
+		"PATH": "${containerEnv:PATH}:/usr/local/bin/liquibase",
+		"PGUSER": "postgres",
+		"PGHOST": "localhost",
+		"DATABASE_NAME": "transactions",
+		"LIQUIBASE_COMMAND_USERNAME": "postgres",
+		"LIQUIBASE_COMMAND_PASSWORD": "postgres",
+		"LIQUIBASE_COMMAND_URL": "jdbc:postgresql://localhost:5432/transactions",
+		"LIQUIBASE_CLASSPATH": "/usr/local/bin/liquibase/internal/lib/postgresql.jar",
+		"LIQUIBASE_HEADLESS": "true",
+		"LIQUIBASE_HUB_MODE": "off",
+		"LIQUIBASE_CHANGELOG_FILE": "dbchangelog.xml",
+		"LIQUIBASE_STRICT": "true"
+	},
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// This can be used to network with other containers or the host.
+	"forwardPorts": [5432],
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	"postCreateCommand": "scripts/create_database.sh &&  scripts/liquibase_update.sh",
+
+	"features": {
+		"java": "lts"
+	},
+
+	// Comment out to connect as root instead. More info: https://aka.ms/vscode-remote/containers/non-root.
+	"remoteUser": "vscode"
+}

.devcontainer/docker-compose.yml

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+version: '3.8'
+
+services:
+  app:
+    build:
+      context: ..
+      dockerfile: .devcontainer/Dockerfile
+      args:
+        # Update 'VARIANT' to pick a version of Python: 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 arm64/Apple Silicon.
+        VARIANT: 3-bullseye
+        # Optional Node.js version to install
+        NODE_VERSION: "lts/*"
+
+    volumes:
+      - ../..:/workspaces:cached 
+
+    # Overrides default command so things don't shut down after the process ends.
+    command: sleep infinity
+
+    # Runs app on the same network as the database container, allows "forwardPorts" in devcontainer.json function.
+    network_mode: service:db
+
+    # Uncomment the next line to use a non-root user for all processes.
+    # user: vscode
+
+    # Use "forwardPorts" in **devcontainer.json** to forward an app port locally.
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+
+  db:
+    image: postgres:latest
+    restart: unless-stopped
+    volumes:
+      - postgres-data:/var/lib/postgresql/data
+    environment:
+      POSTGRES_USER: postgres
+      POSTGRES_DB: postgres
+      POSTGRES_PASSWORD: postgres
+
+    # Add "forwardPorts": ["5432"] to **devcontainer.json** to forward PostgreSQL locally.
+    # (Adding the "ports" property to this file will not forward from a Codespace.)
+
+volumes:
+  postgres-data:

dbchangelog.xml

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+<?xml version="1.1" encoding="UTF-8" standalone="no"?>
+<databaseChangeLog xmlns="http://www.liquibase.org/xml/ns/dbchangelog" xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext" xmlns:pro="http://www.liquibase.org/xml/ns/pro" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd http://www.liquibase.org/xml/ns/dbchangelog http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
+    <property name="now" value="now()" dbms="postgresql"/>
+    <changeSet author="johnboyes" id="1">
+        <createTable tableName="transactions">
+            <column autoIncrement="true" name="id" type="INTEGER">
+                <constraints nullable="false" primaryKey="true" primaryKeyName="transactions_pkey"/>
+            </column>
+            <column name="amount" type="MONEY">
+                <constraints nullable="false"/>
+            </column>
+            <column name="time" type="TIMESTAMP WITHOUT TIME ZONE">
+                <constraints nullable="false"/>
+            </column>
+        </createTable>
+    </changeSet>
+    <changeSet  author="johnboyes"  id="2">  
+    <insert tableName="transactions">  
+        <column name="amount"  value="143.89"/>
+        <column name="time" value="${now}"/>  
+    </insert>
+    <insert tableName="transactions">  
+        <column name="amount"  value="19.27"/>
+        <column name="time" value="${now}"/>  
+    </insert>  
+    <insert tableName="transactions">  
+        <column name="amount"  value="50.00"/>
+        <column name="time" value="${now}"/>  
+    </insert>  
+</changeSet>
+</databaseChangeLog>

scripts/create_database.sh

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+#!/bin/bash
+
+echo "SELECT 'CREATE DATABASE $DATABASE_NAME' WHERE NOT EXISTS (SELECT FROM pg_database WHERE datname = '$DATABASE_NAME')\gexec" | psql

scripts/liquibase_update.sh

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+#!/bin/bash
+
+liquibase \
+  --classpath="$LIQUIBASE_CLASSPATH" \
+  --hub-mode="$LIQUIBASE_HUB_MODE" \
+  --strict="$LIQUIBASE_STRICT" \
+  --headless="$LIQUIBASE_HEADLESS" \
+  update \
+  --changelog-file="$LIQUIBASE_CHANGELOG_FILE" \
+  --url="$LIQUIBASE_COMMAND_URL" \
+  --username="$LIQUIBASE_COMMAND_USERNAME" \
+  --password="$LIQUIBASE_COMMAND_PASSWORD" \