问在Docker容器中运行.Net 5API时无法连接到Postgres

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//var connectionString = Configuration.GetSection(nameof(PostgresSettings)).Get<PostgresSettings>().ConnectionString;
var connectionString = $"Host=tryingtochangehost;Port=5432;Database=databasename;Username=username;Password=password";
services.AddDbContext<DataContext>(options => options.UseNpgsql(connectionString));
services.AddScoped<IDataContext>(provider => provider.GetService<DataContext>());

version: "3.4"

services:
  web:
    build: .
    ports:
      - "8080:80"
    environment:
      - JWTCONFIG:SECRET=secret
      - POSTGRESSETTINGS:PASSWORD=password
      - POSTGRESSETTINGS:HOST=postgresql_database
    depends_on:
      - "postgresql_database"
    networks:
      - mynetwork

  postgresql_database:
    image: postgres:latest
    environment:
      - POSTGRES_USER=admin
      - POSTGRES_PASSWORD=password
      - POSTGRES_DB=databasename
    ports:
      - "5432:5432"
    restart: always
    volumes:
      - database-data:/var/lib/postgresql/data/
    networks:
      - mynetwork

  pgadmin:
    image: dpage/pgadmin4
    environment:
      - PGADMIN_DEFAULT_EMAIL=pgadmin@admin.org
      - PGADMIN_DEFAULT_PASSWORD=password
    ports:
      - "5050:80"
    restart: always
    volumes:
      - pgadmin:/root/.pgadmin
    networks:
      - mynetwork

volumes:
  database-data:
  pgadmin:

networks:
  mynetwork:
    driver: bridge

FROM mcr.microsoft.com/dotnet/aspnet:5.0-focal AS base
WORKDIR /app
EXPOSE 80

FROM mcr.microsoft.com/dotnet/sdk:5.0-focal AS build
WORKDIR /src
COPY ["Server.csproj", "./"]
RUN dotnet restore "Server.csproj"
COPY . .
WORKDIR "/src/."
RUN dotnet build "Server.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "Server.csproj" -c Release -o /app/publish

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "Server.dll"]

{
  "PostgresSettings": {
    "Host": "localhost",
    "Port": "5432",
    "Database": "databasename",
    "Username": "admin"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "JwtConfig": {},
  "AllowedHosts": "*"
}