Resolver Dockerfile

Resolvers run as Docker containers. The Dockerfile defines the container environment. Resolvers listen on port 5553.

Minimal Dockerfile

Dockerfile

FROM oven/bun:1.1.30

WORKDIR /app

# Required: Mark as CyanPrint resolver
LABEL cyanprint.dev=true

# Install dependencies
COPY package.json .
COPY bun.lock .
RUN bun install

# Copy resolver code
COPY . .

# Run resolver
CMD ["bun", "run", "index.ts"]

Dockerfile

FROM python:3.11-slim

WORKDIR /app

# Required: Mark as CyanPrint resolver
LABEL cyanprint.dev=true

# Install dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Copy resolver code
COPY . .

# Run resolver
CMD ["python", "-u", "main.py"]

Dockerfile

FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
WORKDIR /app
ENV ASPNETCORE_URLS=http://+:5553

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
WORKDIR /src
COPY ["MyResolver.csproj", "./"]
RUN dotnet restore "MyResolver.csproj"
COPY . .
RUN dotnet build "MyResolver.csproj" -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "MyResolver.csproj" -c Release -o /app/publish /p:UseAppHost=false

FROM base AS final
WORKDIR /app
COPY --from=publish /app/publish .

# Required: Mark as CyanPrint resolver
LABEL cyanprint.dev=true

ENTRYPOINT ["dotnet", "MyResolver.dll"]

Required Elements

LABEL cyanprint.dev=true

This label identifies the container as a CyanPrint resolver:

LABEL cyanprint.dev=true

Port 5553

Resolvers must listen on port 5553. The SDKs handle this automatically for most languages:

Bun/Node.js SDK: Listens on port 5553 automatically
Python SDK: Listens on port 5553 automatically
.NET SDK: Requires explicit configuration: ENV ASPNETCORE_URLS=http://+:5553

WORKDIR

Set the working directory. The convention is /app:

WORKDIR /app

CMD / ENTRYPOINT

The command that runs the resolver

# Bun
CMD ["bun", "run", "index.ts"]

# Node.js
CMD ["node", "index.js"]

CMD ["python", "-u", "main.py"]

ENTRYPOINT ["dotnet", "MyResolver.dll"]

Full Example with Multi-Stage Build

Dockerfile

# Build stage
FROM oven/bun:1.1.30-alpine AS builder

WORKDIR /app

COPY package.json .
COPY bun.lock .
RUN bun install

COPY . .
RUN bun build index.ts --outdir=dist --target=bun

# Final stage
FROM oven/bun:1.1.30-alpine
LABEL cyanprint.dev=true
WORKDIR /app
COPY --from=builder /app/dist ./dist
CMD ["bun", "run", "dist/index.js"]

Dockerfile

FROM python:3.11-slim

WORKDIR /app

# Create non-root user for security
RUN useradd --create-home --shell /bin/bash appuser

LABEL cyanprint.dev=true

COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

COPY . .

USER appuser

CMD ["python", "-u", "main.py"]

Dockerfile

FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
WORKDIR /app
ENV ASPNETCORE_URLS=http://+:5553

FROM --platform=$BUILDPLATFORM mcr.microsoft.com/dotnet/sdk:8.0 AS build
ARG TARGETARCH
WORKDIR /src
COPY ["MyResolver.csproj", "./"]
RUN dotnet restore -a $TARGETARCH "MyResolver.csproj"
COPY . .
WORKDIR "/src/"
RUN dotnet build "MyResolver.csproj" -a $TARGETARCH -c Release -o /app/build

FROM build AS publish
RUN dotnet publish "MyResolver.csproj" -a $TARGETARCH -c Release -o /app/publish /p:UseAppHost=false

FROM base AS final
LABEL cyanprint.dev=true
WORKDIR /app
COPY --from=publish /app/publish .
ENTRYPOINT ["dotnet", "MyResolver.dll"]

Best Practices

1. Use Specific Versions

# Good: Specific version
FROM oven/bun:1.1.30

# Avoid: Latest (unpredictable)
FROM oven/bun:latest

2. Use .dockerignore

Create a .dockerignore file

node_modules
.git
.gitignore
*.md
tests/
.env*

3. Create Non-Root User

For production deployments

# Create non-root user for security
RUN useradd --create-home --shell /bin/bash appuser
USER appuser

Resolvers should be deterministic. Always include your lockfile to ensure consistent dependency versions across builds.

Project Structure

File layout

cyan.yaml Format

Metadata format

Push to Registry

Publishing guide

Resolver Dockerfile

Project Structure

cyan.yaml Format

Push to Registry

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