initial commit

Author: hmil

.gitignore

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+env

README.md

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+CourseAdvisor infrastructure repository
+=======================================
+
+[ Work in progress ]
+
+This repository contains containers and scripts for setting up the courseadvisor
+backend as well as replication slaves, backup and deployment scripts.
+
+
+## Prerequisites
+
+This repository assumes a regular linux distro with the following programs accessible on the cli:
+- docker
+- mysql
+
+## Usage
+
+TBD. The general idea would be to have frontend.sh expose all functionnalities although
+sub-projects should be as disconnected as possible.
+
+For now, one can create a slave instance like this:
+
+`./frontend.sh slave setup # Creates and starts a replication slave`
+
+And remove it with
+`./frontend.sh slave remove`
+
+The container can be started/stopped using the start and stop commands
+```sh
+./frontend.sh slave stop
+./frontend.sh slave start
+```

db/slave/README.md

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+Replication slave
+=================
+
+Creates a mysql docker container configured to replicate the production server.
+`conf/` is mounted to the container's /etc/mysql/conf.d and contains a configuration file
+edited on the fly to contain appropriate host values.
+
+The container exports it's mysql port to the host's $SLAVE_EXPORTED_PORT (default 3300)

db/slave/slave.sh

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+#!/bin/sh -e
+# server-id   = 2
+# relay-log   = /var/log/mysql/mysql-relay-bin.log
+# log_bin     = /var/log/mysql/mysql-bin.log
+# replicate-do-db   = courseadvisor
+# report-host = hmil.fr
+#
+# position: 107
+
+check_env() {
+  if [ -z "$SLAVE_ROOT_PASSWORD" ] || [ -z "$SLAVE_REPLICATION_PASSWORD" ] || [ -z "$SLAVE_REPLICATION_USER" ]; then
+    echo "An environment variable is missing. Run --help for usage info." 1>&2
+    return 1
+  fi
+  if [ -z "$SLAVE_EXPORTED_PORT" ]; then
+    export SLAVE_EXPORTED_PORT=3300
+  fi
+  if [ -z "$SLAVE_CONTAINER_NAME" ]; then
+    export SLAVE_CONTAINER_NAME="courseadvisor-slave"
+  fi
+}
+
+wait_for_mysql() {
+  set +e
+  failure=1
+  tries=30
+  while [ "$failure" -ne 0 ]; do
+    tries=`expr $tries - 1`
+    if [ $tries -eq 0 ]; then
+      echo "Could not connect to mysql server" 1>&2
+      return 1
+    fi
+    sleep 1
+    echo 'select 1;' | mysql -P$SLAVE_EXPORTED_PORT -h"127.0.0.1" -uroot -p$SLAVE_ROOT_PASSWORD 2>/dev/null
+    failure=$?
+  done
+  return 0
+}
+
+setup() {
+  # prepare configuration with random slave number
+  server_id=`tr -cd 0-9 </dev/urandom | head -c 6`
+  server_name=`hostname`
+  cat slave_config.cnf | sed "s/__SERVER_ID__/$server_id/" | sed "s/__SERVER_NAME__/$server_name/" > conf/slave_config.cnf
+  # Create mysql docker image
+  docker run --name ${SLAVE_CONTAINER_NAME} -p ${SLAVE_EXPORTED_PORT}:3306 -e MYSQL_ROOT_PASSWORD=${SLAVE_ROOT_PASSWORD} -e MYSQL_DATABASE=master -v `pwd`/conf:/etc/mysql/conf.d -d mysql:5.5
+  echo "Waiting for mysql deamon to start"
+  wait_for_mysql 1>/dev/null
+  echo "Dumping master state (warning: locks master DB)"
+  # Seeds database with snapshot data, replication log position is set to take over right after this snapshot
+  mysqldump -P5467 -u${SLAVE_REPLICATION_USER} -h"courseadvisor.ch" -p${SLAVE_REPLICATION_PASSWORD} --master-data -B master |
+    sed "s/CHANGE MASTER TO/CHANGE MASTER TO MASTER_HOST='courseadvisor.ch',MASTER_PORT=5467,MASTER_USER='${SLAVE_REPLICATION_USER}',MASTER_PASSWORD='${SLAVE_REPLICATION_PASSWORD}',/" |
+    mysql -P${SLAVE_EXPORTED_PORT} -h"127.0.0.1" -uroot -p${SLAVE_ROOT_PASSWORD}
+
+  echo "Starting slave replication"
+  # Sets up remote master
+  echo "START SLAVE;" | mysql -P${SLAVE_EXPORTED_PORT} -h"127.0.0.1" -uroot -p${SLAVE_ROOT_PASSWORD}
+  echo "Slave instance is running"
+}
+
+stop() {
+  docker stop $SLAVE_CONTAINER_NAME
+}
+
+remove() {
+  stop
+  docker rm $SLAVE_CONTAINER_NAME
+}
+
+start() {
+  docker start $SLAVE_CONTAINER_NAME
+}
+
+usage() {
+  cat 1>&2 <<EOF
+  usage: slave (setup|remove)
+
+Sets up or removes the slave docker image. Sensible arguments are passed via env variables:
+
+mandatory:
+SLAVE_REPLICATION_USER     : Replication user on master host
+SLAVE_REPLICATION_PASSWORD : Replication user password on master host
+SLAVE_ROOT_PASSWORD        : Password for root user on local slave instance
+
+optionnal:
+SLAVE_EXPORTED_PORT : Which host port to bind to slave's SQL (default 3300)
+SLAVE_CONTAINER_NAME: Docker container name for the slave (default courseadvisor-slave)
+EOF
+}
+
+check_env
+
+case "$1" in
+  "setup")
+     setup
+  ;;
+  "remove")
+    remove
+  ;;
+  "stop")
+    stop
+  ;;
+  "start")
+    start
+  ;;
+  *)
+    usage
+  ;;
+esac

db/slave/slave_config.cnf

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+[mysqld]
+server-id   = __SERVER_ID__
+#relay-log   = /var/log/mysql/mysql-relay-bin.log
+#log_bin     = /var/log/mysql/mysql-bin.log
+replicate-do-db   = master
+report_host = __SERVER_NAME__

frontend.sh

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+#!/bin/sh
+
+usage() {
+  cat 1>&2 <<EOF
+  usage: frontend.sh (command [args] | help)
+
+Available commands:
+  slave : Replication slave
+  help : Prints this help message
+
+For command-specific usage instructions, run frontend.sh command --help
+EOF
+}
+
+
+if [ $# -lt 2 ]; then
+  usage
+  exit 1
+fi
+
+if [ ! -e `pwd`/env ]; then
+  echo "Please provide the environment variables file './env'" 1>&2
+  exit 1
+fi
+
+. `pwd`/env
+
+prog="$1"
+shift
+
+case "$prog" in
+  help|--help|-h)
+    usage
+    exit 0
+  ;;
+  slave)
+    cd db/slave
+    ./slave.sh $@
+  ;;
+  *)
+    usage
+  ;;
+esac