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authorLewis Marshall <lewis@lmars.net>2017-06-01 18:52:18 +0800
committerFelix Lange <fjl@users.noreply.github.com>2017-06-01 18:52:18 +0800
commit0036e2a74761413200ce3a8ed316ecb721895f60 (patch)
tree1ac94ec2c89a9055999056cd6d99e2955c4409fd /swarm
parent727eadacca761e4abb4273a87dc601bb79d3167d (diff)
downloaddexon-0036e2a74761413200ce3a8ed316ecb721895f60.tar.gz
dexon-0036e2a74761413200ce3a8ed316ecb721895f60.tar.zst
dexon-0036e2a74761413200ce3a8ed316ecb721895f60.zip
swarm/dev: add development environment (#14332)
This PR adds a Swarm development environment which can be run in a Docker container and provides scripts for building binaries and running Swarm clusters.
Diffstat (limited to 'swarm')
-rw-r--r--swarm/dev/.dockerignore2
-rw-r--r--swarm/dev/.gitignore2
-rw-r--r--swarm/dev/Dockerfile42
-rw-r--r--swarm/dev/Makefile14
-rw-r--r--swarm/dev/README.md20
-rw-r--r--swarm/dev/bashrc21
-rwxr-xr-xswarm/dev/run.sh90
-rwxr-xr-xswarm/dev/scripts/boot-cluster.sh288
-rwxr-xr-xswarm/dev/scripts/random-uploads.sh96
-rwxr-xr-xswarm/dev/scripts/stop-cluster.sh98
-rw-r--r--swarm/dev/scripts/util.sh53
11 files changed, 726 insertions, 0 deletions
diff --git a/swarm/dev/.dockerignore b/swarm/dev/.dockerignore
new file mode 100644
index 000000000..f9e69b37f
--- /dev/null
+++ b/swarm/dev/.dockerignore
@@ -0,0 +1,2 @@
+bin/*
+cluster/*
diff --git a/swarm/dev/.gitignore b/swarm/dev/.gitignore
new file mode 100644
index 000000000..f9e69b37f
--- /dev/null
+++ b/swarm/dev/.gitignore
@@ -0,0 +1,2 @@
+bin/*
+cluster/*
diff --git a/swarm/dev/Dockerfile b/swarm/dev/Dockerfile
new file mode 100644
index 000000000..728bdab1f
--- /dev/null
+++ b/swarm/dev/Dockerfile
@@ -0,0 +1,42 @@
+FROM ubuntu:xenial
+
+# install build + test dependencies
+RUN apt-get update && \
+ apt-get install --yes --no-install-recommends \
+ ca-certificates \
+ curl \
+ fuse \
+ g++ \
+ gcc \
+ git \
+ iproute2 \
+ iputils-ping \
+ less \
+ libc6-dev \
+ make \
+ pkg-config \
+ && \
+ apt-get clean
+
+# install Go
+ENV GO_VERSION 1.8.1
+RUN curl -fSLo golang.tar.gz "https://golang.org/dl/go${GO_VERSION}.linux-amd64.tar.gz" && \
+ tar -xzf golang.tar.gz -C /usr/local && \
+ rm golang.tar.gz
+ENV GOPATH /go
+ENV PATH $GOPATH/bin:/usr/local/go/bin:$PATH
+
+# install docker CLI
+RUN curl -fSLo docker.tar.gz https://get.docker.com/builds/Linux/x86_64/docker-17.04.0-ce.tgz && \
+ tar -xzf docker.tar.gz -C /usr/local/bin --strip-components=1 docker/docker && \
+ rm docker.tar.gz
+
+# install jq
+RUN curl -fSLo /usr/local/bin/jq https://github.com/stedolan/jq/releases/download/jq-1.5/jq-linux64 && \
+ chmod +x /usr/local/bin/jq
+
+# install govendor
+RUN go get -u github.com/kardianos/govendor
+
+# add custom bashrc
+ADD bashrc /root/.bashrc
diff --git a/swarm/dev/Makefile b/swarm/dev/Makefile
new file mode 100644
index 000000000..365964b7f
--- /dev/null
+++ b/swarm/dev/Makefile
@@ -0,0 +1,14 @@
+.PHONY: build cluster test
+
+default: build
+
+build:
+ go build -o bin/swarm github.com/ethereum/go-ethereum/cmd/swarm
+ go build -o bin/geth github.com/ethereum/go-ethereum/cmd/geth
+ go build -o bin/bootnode github.com/ethereum/go-ethereum/cmd/bootnode
+
+cluster: build
+ scripts/boot-cluster.sh
+
+test:
+ go test -v github.com/ethereum/go-ethereum/swarm/...
diff --git a/swarm/dev/README.md b/swarm/dev/README.md
new file mode 100644
index 000000000..81e3b5358
--- /dev/null
+++ b/swarm/dev/README.md
@@ -0,0 +1,20 @@
+Swarm development environment
+=============================
+
+The Swarm development environment is a Linux bash shell which can be run in a
+Docker container and provides a predictable build and test environment.
+
+### Start the Docker container
+
+Run the `run.sh` script to build the Docker image and run it, you will then be
+at a bash prompt inside the `swarm/dev` directory.
+
+### Build binaries
+
+Run `make` to build the `swarm`, `geth` and `bootnode` binaries into the
+`swarm/dev/bin` directory.
+
+### Boot a cluster
+
+Run `make cluster` to start a 3 node Swarm cluster, or run
+`scripts/boot-cluster.sh --size N` to boot a cluster of size N.
diff --git a/swarm/dev/bashrc b/swarm/dev/bashrc
new file mode 100644
index 000000000..efb504fa3
--- /dev/null
+++ b/swarm/dev/bashrc
@@ -0,0 +1,21 @@
+export ROOT="${GOPATH}/src/github.com/ethereum/go-ethereum"
+export PATH="${ROOT}/swarm/dev/bin:${PATH}"
+
+cd "${ROOT}/swarm/dev"
+
+cat <<WELCOME
+
+=============================================
+
+Welcome to the swarm development environment.
+
+- Run 'make' to build the swarm, geth and bootnode binaries
+- Run 'make test' to run the swarm unit tests
+- Run 'make cluster' to start a swarm cluster
+- Run 'exit' to exit the development environment
+
+See the 'scripts' directory for some useful scripts.
+
+=============================================
+
+WELCOME
diff --git a/swarm/dev/run.sh b/swarm/dev/run.sh
new file mode 100755
index 000000000..2ad600ded
--- /dev/null
+++ b/swarm/dev/run.sh
@@ -0,0 +1,90 @@
+#!/usr/bin/env bash
+#
+# A script to build and run the Swarm development environment using Docker.
+
+set -e
+
+ROOT="$(cd "$(dirname "$0")/../.." && pwd)"
+
+# DEFAULT_NAME is the default name for the Docker image and container
+DEFAULT_NAME="swarm-dev"
+
+usage() {
+ cat >&2 <<USAGE
+usage: $0 [options]
+
+Build and run the Swarm development environment.
+
+Depends on Docker being installed locally.
+
+OPTIONS:
+ -n, --name NAME Docker image and container name [default: ${DEFAULT_NAME}]
+ -d, --docker-args ARGS Custom args to pass to 'docker run' (e.g. '-p 8000:8000' to expose a port)
+ -h, --help Show this message
+USAGE
+}
+
+main() {
+ local name="${DEFAULT_NAME}"
+ local docker_args=""
+ parse_args "$@"
+ build_image
+ run_image
+}
+
+parse_args() {
+ while true; do
+ case "$1" in
+ -h | --help)
+ usage
+ exit 0
+ ;;
+ -n | --name)
+ if [[ -z "$2" ]]; then
+ echo "ERROR: --name flag requires an argument" >&2
+ exit 1
+ fi
+ name="$2"
+ shift 2
+ ;;
+ -d | --docker-args)
+ if [[ -z "$2" ]]; then
+ echo "ERROR: --docker-args flag requires an argument" >&2
+ exit 1
+ fi
+ docker_args="$2"
+ shift 2
+ ;;
+ *)
+ break
+ ;;
+ esac
+ done
+
+ if [[ $# -ne 0 ]]; then
+ usage
+ echo "ERROR: invalid arguments" >&2
+ exit 1
+ fi
+}
+
+build_image() {
+ docker build --tag "${name}" "${ROOT}/swarm/dev"
+}
+
+run_image() {
+ exec docker run \
+ --privileged \
+ --interactive \
+ --tty \
+ --rm \
+ --hostname "${name}" \
+ --name "${name}" \
+ --volume "${ROOT}:/go/src/github.com/ethereum/go-ethereum" \
+ --volume "/var/run/docker.sock:/var/run/docker.sock" \
+ ${docker_args} \
+ "${name}" \
+ /bin/bash
+}
+
+main "$@"
diff --git a/swarm/dev/scripts/boot-cluster.sh b/swarm/dev/scripts/boot-cluster.sh
new file mode 100755
index 000000000..073b095ad
--- /dev/null
+++ b/swarm/dev/scripts/boot-cluster.sh
@@ -0,0 +1,288 @@
+#!/bin/bash
+#
+# A script to boot a dev swarm cluster on a Linux host (typically in a Docker
+# container started with swarm/dev/run.sh).
+#
+# The cluster contains a bootnode, a geth node and multiple swarm nodes, with
+# each node having its own data directory in a base directory passed with the
+# --dir flag (default is swarm/dev/cluster).
+#
+# To avoid using different ports for each node and to make networking more
+# realistic, each node gets its own network namespace with IPs assigned from
+# the 192.168.33.0/24 subnet:
+#
+# bootnode: 192.168.33.2
+# geth: 192.168.33.3
+# swarm: 192.168.33.10{1,2,...,n}
+
+set -e
+
+ROOT="$(cd "$(dirname "$0")/../../.." && pwd)"
+source "${ROOT}/swarm/dev/scripts/util.sh"
+
+# DEFAULT_BASE_DIR is the default base directory to store node data
+DEFAULT_BASE_DIR="${ROOT}/swarm/dev/cluster"
+
+# DEFAULT_CLUSTER_SIZE is the default swarm cluster size
+DEFAULT_CLUSTER_SIZE=3
+
+# Linux bridge configuration for connecting the node network namespaces
+BRIDGE_NAME="swarmbr0"
+BRIDGE_IP="192.168.33.1"
+
+# static bootnode configuration
+BOOTNODE_IP="192.168.33.2"
+BOOTNODE_PORT="30301"
+BOOTNODE_KEY="32078f313bea771848db70745225c52c00981589ad6b5b49163f0f5ee852617d"
+BOOTNODE_PUBKEY="760c4460e5336ac9bbd87952a3c7ec4363fc0a97bd31c86430806e287b437fd1b01abc6e1db640cf3106b520344af1d58b00b57823db3e1407cbc433e1b6d04d"
+BOOTNODE_URL="enode://${BOOTNODE_PUBKEY}@${BOOTNODE_IP}:${BOOTNODE_PORT}"
+
+# static geth configuration
+GETH_IP="192.168.33.3"
+GETH_RPC_PORT="8545"
+GETH_RPC_URL="http://${GETH_IP}:${GETH_RPC_PORT}"
+
+usage() {
+ cat >&2 <<USAGE
+usage: $0 [options]
+
+Boot a dev swarm cluster.
+
+OPTIONS:
+ -d, --dir DIR Base directory to store node data [default: ${DEFAULT_BASE_DIR}]
+ -s, --size SIZE Size of swarm cluster [default: ${DEFAULT_CLUSTER_SIZE}]
+ -h, --help Show this message
+USAGE
+}
+
+main() {
+ local base_dir="${DEFAULT_BASE_DIR}"
+ local cluster_size="${DEFAULT_CLUSTER_SIZE}"
+
+ parse_args "$@"
+
+ local pid_dir="${base_dir}/pids"
+ local log_dir="${base_dir}/logs"
+ mkdir -p "${base_dir}" "${pid_dir}" "${log_dir}"
+
+ stop_cluster
+ create_network
+ start_bootnode
+ start_geth_node
+ start_swarm_nodes
+}
+
+parse_args() {
+ while true; do
+ case "$1" in
+ -h | --help)
+ usage
+ exit 0
+ ;;
+ -d | --dir)
+ if [[ -z "$2" ]]; then
+ fail "--dir flag requires an argument"
+ fi
+ base_dir="$2"
+ shift 2
+ ;;
+ -s | --size)
+ if [[ -z "$2" ]]; then
+ fail "--size flag requires an argument"
+ fi
+ cluster_size="$2"
+ shift 2
+ ;;
+ *)
+ break
+ ;;
+ esac
+ done
+
+ if [[ $# -ne 0 ]]; then
+ usage
+ fail "ERROR: invalid arguments: $@"
+ fi
+}
+
+stop_cluster() {
+ info "stopping existing cluster"
+ "${ROOT}/swarm/dev/scripts/stop-cluster.sh" --dir "${base_dir}"
+}
+
+# create_network creates a Linux bridge which is used to connect the node
+# network namespaces together
+create_network() {
+ local subnet="${BRIDGE_IP}/24"
+
+ info "creating ${subnet} network on ${BRIDGE_NAME}"
+ ip link add name "${BRIDGE_NAME}" type bridge
+ ip link set dev "${BRIDGE_NAME}" up
+ ip address add "${subnet}" dev "${BRIDGE_NAME}"
+}
+
+# start_bootnode starts a bootnode which is used to bootstrap the geth and
+# swarm nodes
+start_bootnode() {
+ local key_file="${base_dir}/bootnode.key"
+ echo -n "${BOOTNODE_KEY}" > "${key_file}"
+
+ local args=(
+ --addr "${BOOTNODE_IP}:${BOOTNODE_PORT}"
+ --nodekey "${key_file}"
+ --verbosity "6"
+ )
+
+ start_node "bootnode" "${BOOTNODE_IP}" "$(which bootnode)" ${args[@]}
+}
+
+# start_geth_node starts a geth node with --datadir pointing at <base-dir>/geth
+# and a single, unlocked account with password "geth"
+start_geth_node() {
+ local dir="${base_dir}/geth"
+ mkdir -p "${dir}"
+
+ local password="geth"
+ echo "${password}" > "${dir}/password"
+
+ # create an account if necessary
+ if [[ ! -e "${dir}/keystore" ]]; then
+ info "creating geth account"
+ create_account "${dir}" "${password}"
+ fi
+
+ # get the account address
+ local address="$(jq --raw-output '.address' ${dir}/keystore/*)"
+ if [[ -z "${address}" ]]; then
+ fail "failed to get geth account address"
+ fi
+
+ local args=(
+ --datadir "${dir}"
+ --networkid "321"
+ --bootnodes "${BOOTNODE_URL}"
+ --unlock "${address}"
+ --password "${dir}/password"
+ --rpc
+ --rpcaddr "${GETH_IP}"
+ --rpcport "${GETH_RPC_PORT}"
+ --verbosity "6"
+ )
+
+ start_node "geth" "${GETH_IP}" "$(which geth)" ${args[@]}
+}
+
+start_swarm_nodes() {
+ for i in $(seq 1 ${cluster_size}); do
+ start_swarm_node "${i}"
+ done
+}
+
+# start_swarm_node starts a swarm node with a name like "swarmNN" (where NN is
+# a zero-padded integer like "07"), --datadir pointing at <base-dir>/<name>
+# (e.g. <base-dir>/swarm07) and a single account with <name> as the password
+start_swarm_node() {
+ local num=$1
+ local name="swarm$(printf '%02d' ${num})"
+ local ip="192.168.33.1$(printf '%02d' ${num})"
+
+ local dir="${base_dir}/${name}"
+ mkdir -p "${dir}"
+
+ local password="${name}"
+ echo "${password}" > "${dir}/password"
+
+ # create an account if necessary
+ if [[ ! -e "${dir}/keystore" ]]; then
+ info "creating account for ${name}"
+ create_account "${dir}" "${password}"
+ fi
+
+ # get the account address
+ local address="$(jq --raw-output '.address' ${dir}/keystore/*)"
+ if [[ -z "${address}" ]]; then
+ fail "failed to get swarm account address"
+ fi
+
+ local args=(
+ --bootnodes "${BOOTNODE_URL}"
+ --datadir "${dir}"
+ --identity "${name}"
+ --ethapi "${GETH_RPC_URL}"
+ --bzznetworkid "321"
+ --bzzaccount "${address}"
+ --password "${dir}/password"
+ --verbosity "6"
+ )
+
+ start_node "${name}" "${ip}" "$(which swarm)" ${args[@]}
+}
+
+# start_node runs the node command as a daemon in a network namespace
+start_node() {
+ local name="$1"
+ local ip="$2"
+ local path="$3"
+ local cmd_args=${@:4}
+
+ info "starting ${name} with IP ${ip}"
+
+ create_node_network "${name}" "${ip}"
+
+ # add a marker to the log file
+ cat >> "${log_dir}/${name}.log" <<EOF
+
+>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+Starting ${name} node - $(date)
+>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+
+EOF
+
+ # run the command in the network namespace using start-stop-daemon to
+ # daemonise the process, sending all output to the log file
+ local daemon_args=(
+ --start
+ --background
+ --no-close
+ --make-pidfile
+ --pidfile "${pid_dir}/${name}.pid"
+ --exec "${path}"
+ )
+ if ! ip netns exec "${name}" start-stop-daemon ${daemon_args[@]} -- $cmd_args &>> "${log_dir}/${name}.log"; then
+ fail "could not start ${name}, check ${log_dir}/${name}.log"
+ fi
+}
+
+# create_node_network creates a network namespace and connects it to the Linux
+# bridge using a veth pair
+create_node_network() {
+ local name="$1"
+ local ip="$2"
+
+ # create the namespace
+ ip netns add "${name}"
+
+ # create the veth pair
+ local veth0="veth${name}0"
+ local veth1="veth${name}1"
+ ip link add name "${veth0}" type veth peer name "${veth1}"
+
+ # add one end to the bridge
+ ip link set dev "${veth0}" master "${BRIDGE_NAME}"
+ ip link set dev "${veth0}" up
+
+ # add the other end to the namespace, rename it eth0 and give it the ip
+ ip link set dev "${veth1}" netns "${name}"
+ ip netns exec "${name}" ip link set dev "${veth1}" name "eth0"
+ ip netns exec "${name}" ip link set dev "eth0" up
+ ip netns exec "${name}" ip address add "${ip}/24" dev "eth0"
+}
+
+create_account() {
+ local dir=$1
+ local password=$2
+
+ geth --datadir "${dir}" --password /dev/stdin account new <<< "${password}"
+}
+
+main "$@"
diff --git a/swarm/dev/scripts/random-uploads.sh b/swarm/dev/scripts/random-uploads.sh
new file mode 100755
index 000000000..db7887e3c
--- /dev/null
+++ b/swarm/dev/scripts/random-uploads.sh
@@ -0,0 +1,96 @@
+#!/bin/bash
+#
+# A script to upload random data to a swarm cluster.
+#
+# Example:
+#
+# random-uploads.sh --addr 192.168.33.101:8500 --size 40k --count 1000
+
+set -e
+
+ROOT="$(cd "$(dirname "$0")/../../.." && pwd)"
+source "${ROOT}/swarm/dev/scripts/util.sh"
+
+DEFAULT_ADDR="localhost:8500"
+DEFAULT_UPLOAD_SIZE="40k"
+DEFAULT_UPLOAD_COUNT="1000"
+
+usage() {
+ cat >&2 <<USAGE
+usage: $0 [options]
+
+Upload random data to a Swarm cluster.
+
+OPTIONS:
+ -a, --addr ADDR Swarm API address [default: ${DEFAULT_ADDR}]
+ -s, --size SIZE Individual upload size [default: ${DEFAULT_UPLOAD_SIZE}]
+ -c, --count COUNT Number of uploads [default: ${DEFAULT_UPLOAD_COUNT}]
+ -h, --help Show this message
+USAGE
+}
+
+main() {
+ local addr="${DEFAULT_ADDR}"
+ local upload_size="${DEFAULT_UPLOAD_SIZE}"
+ local upload_count="${DEFAULT_UPLOAD_COUNT}"
+
+ parse_args "$@"
+
+ info "uploading ${upload_count} ${upload_size} random files to ${addr}"
+
+ for i in $(seq 1 ${upload_count}); do
+ info "upload ${i} / ${upload_count}:"
+ do_random_upload
+ echo
+ done
+}
+
+do_random_upload() {
+ curl -fsSL -X POST --data-binary "$(random_data)" "http://${addr}/bzzr:/"
+}
+
+random_data() {
+ dd if=/dev/urandom of=/dev/stdout bs="${upload_size}" count=1 2>/dev/null
+}
+
+parse_args() {
+ while true; do
+ case "$1" in
+ -h | --help)
+ usage
+ exit 0
+ ;;
+ -a | --addr)
+ if [[ -z "$2" ]]; then
+ fail "--addr flag requires an argument"
+ fi
+ addr="$2"
+ shift 2
+ ;;
+ -s | --size)
+ if [[ -z "$2" ]]; then
+ fail "--size flag requires an argument"
+ fi
+ upload_size="$2"
+ shift 2
+ ;;
+ -c | --count)
+ if [[ -z "$2" ]]; then
+ fail "--count flag requires an argument"
+ fi
+ upload_count="$2"
+ shift 2
+ ;;
+ *)
+ break
+ ;;
+ esac
+ done
+
+ if [[ $# -ne 0 ]]; then
+ usage
+ fail "ERROR: invalid arguments: $@"
+ fi
+}
+
+main "$@"
diff --git a/swarm/dev/scripts/stop-cluster.sh b/swarm/dev/scripts/stop-cluster.sh
new file mode 100755
index 000000000..89cb7b0c9
--- /dev/null
+++ b/swarm/dev/scripts/stop-cluster.sh
@@ -0,0 +1,98 @@
+#!/bin/bash
+#
+# A script to shutdown a dev swarm cluster.
+
+set -e
+
+ROOT="$(cd "$(dirname "$0")/../../.." && pwd)"
+source "${ROOT}/swarm/dev/scripts/util.sh"
+
+DEFAULT_BASE_DIR="${ROOT}/swarm/dev/cluster"
+
+usage() {
+ cat >&2 <<USAGE
+usage: $0 [options]
+
+Shutdown a dev swarm cluster.
+
+OPTIONS:
+ -d, --dir DIR Base directory [default: ${DEFAULT_BASE_DIR}]
+ -h, --help Show this message
+USAGE
+}
+
+main() {
+ local base_dir="${DEFAULT_BASE_DIR}"
+
+ parse_args "$@"
+
+ local pid_dir="${base_dir}/pids"
+
+ stop_swarm_nodes
+ stop_node "geth"
+ stop_node "bootnode"
+ delete_network
+}
+
+parse_args() {
+ while true; do
+ case "$1" in
+ -h | --help)
+ usage
+ exit 0
+ ;;
+ -d | --dir)
+ if [[ -z "$2" ]]; then
+ fail "--dir flag requires an argument"
+ fi
+ base_dir="$2"
+ shift 2
+ ;;
+ *)
+ break
+ ;;
+ esac
+ done
+
+ if [[ $# -ne 0 ]]; then
+ usage
+ fail "ERROR: invalid arguments: $@"
+ fi
+}
+
+stop_swarm_nodes() {
+ for name in $(ls "${pid_dir}" | grep -oP 'swarm\d+'); do
+ stop_node "${name}"
+ done
+}
+
+stop_node() {
+ local name=$1
+ local pid_file="${pid_dir}/${name}.pid"
+
+ if [[ -e "${pid_file}" ]]; then
+ info "stopping ${name}"
+ start-stop-daemon \
+ --stop \
+ --pidfile "${pid_file}" \
+ --remove-pidfile \
+ --oknodo \
+ --retry 15
+ fi
+
+ if ip netns list | grep -qF "${name}"; then
+ ip netns delete "${name}"
+ fi
+
+ if ip link show "veth${name}0" &>/dev/null; then
+ ip link delete dev "veth${name}0"
+ fi
+}
+
+delete_network() {
+ if ip link show "swarmbr0" &>/dev/null; then
+ ip link delete dev "swarmbr0"
+ fi
+}
+
+main "$@"
diff --git a/swarm/dev/scripts/util.sh b/swarm/dev/scripts/util.sh
new file mode 100644
index 000000000..f17a12e42
--- /dev/null
+++ b/swarm/dev/scripts/util.sh
@@ -0,0 +1,53 @@
+# shared shell functions
+
+info() {
+ local msg="$@"
+ local timestamp="$(date +%H:%M:%S)"
+ say "===> ${timestamp} ${msg}" "green"
+}
+
+warn() {
+ local msg="$@"
+ local timestamp=$(date +%H:%M:%S)
+ say "===> ${timestamp} WARN: ${msg}" "yellow" >&2
+}
+
+fail() {
+ local msg="$@"
+ say "ERROR: ${msg}" "red" >&2
+ exit 1
+}
+
+# say prints the given message to STDOUT, using the optional color if
+# STDOUT is a terminal.
+#
+# usage:
+#
+# say "foo" - prints "foo"
+# say "bar" "red" - prints "bar" in red
+# say "baz" "green" - prints "baz" in green
+# say "qux" "red" | tee - prints "qux" with no colour
+#
+say() {
+ local msg=$1
+ local color=$2
+
+ if [[ -n "${color}" ]] && [[ -t 1 ]]; then
+ case "${color}" in
+ red)
+ echo -e "\033[1;31m${msg}\033[0m"
+ ;;
+ green)
+ echo -e "\033[1;32m${msg}\033[0m"
+ ;;
+ yellow)
+ echo -e "\033[1;33m${msg}\033[0m"
+ ;;
+ *)
+ echo "${msg}"
+ ;;
+ esac
+ else
+ echo "${msg}"
+ fi
+}