# Zcash Docker Development Environment

🛑 **This is a work-in-progress and may not function reliably. It is certainly not
intended to be used in production.** 🛑

This repository contains a Dockerfile that will help you get started building
Zcash's mobile app wallet stack. The projects' code is kept on your host
filesystem and shared into the docker container, so you can keep using the
editors and tools you're familiar with, and only use the container to run
builds. You can also run the `zcashd` and `lightwalletd` services within the
container.

The development environment currently supports building:

- `zcashd`
- `librustzcash` (preview branch)
- `lightwalletd` (preview branch)
- `zcash-android-wallet-sdk` (preview branch)
- `zcash-android-wallet-poc`

## Quick Start

**Requirements:** Docker, 30GB free disk space.

First, checkout this repository:

```
git checkout <this-repository's-url>
cd zdev-docker
```
Next, build the Docker image. This will create an image called `zdev` which
has all of the build dependencies pre-installed:

```
docker build -t zdev docker
```

Now, clone all of the projects you want to work on into the `mount/` directory:

```
cd mount
git clone git@github.com:zcash/zcash.git
git clone git@github.com:zcash-hackworks/lightwalletd.git
git clone git@github.com:str4d/librustzcash.git --branch preview
git clone git@github.com:zcash/zcash-android-wallet-sdk.git --branch preview
git clone git@github.com:zcash/zcash-android-wallet-poc.git
cd ..
```

You can now launch a new container instance of `zdev` and have access to your
clones of `zcash`, `lightwalletd`, etc. from within:

```
docker run -it --mount type=bind,source="$(pwd)"/mount,target=/mount zdev
```

The `./mount` directory will be shared between the host and the container,
accessible in the container at `/mount`. The changes you make to files inside
`/mount` in the container will change the files in `./mount`.

The previous command opened a shell inside the container. You can run build
commands, for example:

```
cd /mount/zcash
./zcutil/build.sh -j$(nproc)
./zcutil/fetch-params.sh
./qa/zcash/full-test-suite.py
```

See the individual projects' documentation for build instructions.

To open another shell into the running container, run `docker container ls`,
copy the container ID, and then run `docker exec -it <container ID> bash`. You
can start and stop the container with `docker start` and `docker stop`.

To update the Ubuntu packages in the `zdev` image or make changes to which
dependencies are installed, edit the `docker/install-build-dependencies.sh`
script and then re-build the `zdev` image using the same command as above. The
changes will take effect in the next *new* container instance you launch. You
can of course also just make changes directly to the container instead of
updating the image every time.

## Build Cheat Sheet

**Note:** All of the builds are independent for now, i.e. the build output of
`librustzcash` *doesn't* get used as an input to the `zcash-android-wallet-sdk`
build.

**`zcashd`**

```
cd /mount/zcash
./zcutil/build.sh -j$(nproc)
```

**`librustzcash`**

```
cd /mount/librustzcash
cargo build --release
```

**`lightwalletd`**

```
cd /mount/lightwalletd
go run cmd/injest/main.go <...>
go run cmd/server/main.go <...>
```

**`zcash-android-wallet-sdk`**

```
cd /mount/zcash-android-wallet-sdk
./gradlew clean assembleZcashtestnetRelease
```

**`zcash-android-wallet-poc`**

First, generate a `google-services.json` file from [Google
Firebase](https://firebase.google.com/) and put it in
`zcash-android-wallet-poc/zcash-android-wallet-app/app/google-services.json`.

```
cd /mount/zcash-android-wallet-poc
cd zcash-android-wallet-app
./gradlew clean assembleZcashtestnetDebug
```

## Running the Stack

This section will help you set up:

1. A `zcashd` node connected to testnet.
2. A `lightwalletd` injestor which receives blocks from the `zcashd` node.
3. A `lightwalletd` server which serves the blocks parsed by the injestor to
   light clients.

First, start the `lightwalletd` injestor:

```
cd /mount/lightwalletd
go run cmd/ingest/main.go -db-path database.db -log-file injestor-log.txt
```

This will listen on port 28332 for a ZMQ connection from `zcashd`. Now put the
following contents in `/root/.zcash/zcash.conf`:

```
testnet=1
addnode=testnet.z.cash
zmqpubcheckedblock=tcp://127.0.0.1:28332
rpcuser=yourusername
rpcpassword=yourpassword
```

You're advised to change `yourusername` and `yourpassword` to something random.
This configures `zcashd` to sync with the testnet and send blocks to
`lightwalletd` on localhost port 28332. Now build and run `zcashd`:

```
cd /mount/zcash
./zcutil/build.sh -j$(nproc)
./zcutil/fetch-params.sh
./src/zcashd
```

If you check the contents of `/mount/lighwalletd/injestor-log.txt`, you should
see that it is receiving blocks as the `zcashd` node syncs.

To serve these blocks to light clients, start the server:

```
cd /mount/lightwalletd
go run cmd/server/main.go -conf-file /root/.zcash/zcash.conf -db-path database.db -log-file server-log.txt
```
**Note:** If this command fails and there's an error message about database
locks in `server-log.txt` you need to stop the injestor, start the server, then
re-start the injestor.

## TODOs

- Verify the "running the stack" instructions are actually correct.
- Finish instructions for building & connecting the app.
- Put `.zcash-params` in the image.
- Put `.zcash-mainnet` and `.zcash-testnet` fully loaded into the image.
- Make the builds use the output of dependencies' builds
- Security review (are tools/code being downloaded safely? etc)