当通过Docker多级构建复制到容器中时，无法从位于项目根目录的Golang打开简单文件。但是我可以看到容器中的文件。
下面是我的Dockerfile：

# Start from a base Go image
FROM golang:1.19 as builder

# Set the working directory inside the container
WORKDIR /app

# Copy the Go module files
COPY go.mod go.sum ./

# Download the dependencies
RUN go mod download

# Copy the rest of the application code
COPY . .

# Copy the promotions.csv into the container
RUN chmod +r /app/promotions.csv
COPY promotions.csv /app/promotions.csv

# Run with disabled cross-compilation
RUN CGO_ENABLED=0 GOOS=linux go build -o app .

# Final stage
FROM alpine:3.18

RUN apk --no-cache add ca-certificates

WORKDIR /root/

COPY --from=builder --chown=${USERNAME}:${USERNAME} /app/app .

EXPOSE 1321

CMD ["./app"]

promotions.csv文件存在于容器文件系统中：

但是，main.go中的records, err := readCSVFile("promotions.csv")代码返回错误：
打开促销.csv：没有这样的文件或目录
更奇怪的是，当我不使用多阶段构建时，一切都工作得很好：

# Start from a base Go image
FROM golang:1.19 as builder

# Set the working directory inside the container
WORKDIR /app

# Copy the Go module files
COPY go.mod go.sum ./

# Download the dependencies
RUN go mod download

#COPY promotions.csv ./

# Copy the rest of the application code
COPY . .

# Copy the promotions folder into the container

# Run with disabled cross-compilation
RUN go build -o main

EXPOSE 1321

CMD ["./main"]

下面是docker-compose.yml：

version: '3'

services:
  postgres:
    image: postgres:15.3-alpine
    restart: always
    ports:
      - 5432:5432
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: password
      POSTGRES_DB: vrstore

  app:
    build:
      context: .
      dockerfile: Dockerfile
    restart: always
    ports:
      - 1321:1321
    depends_on:
      - postgres
    volumes:
      - .:/app
    environment:
      DATABASE_HOST: postgres
      DATABASE_PORT: 5432
      DATABASE_NAME: vrstore
      DATABASE_USER: postgres
      DATABASE_PASSWORD: password

在第一种情况下，错误的原因可能是什么？也许我错过了一些明显的东西。谢谢