life0fun / colorcloud

cloud storage for a school in the cloud with datomic as data server

Color Cloud

Inspired by Dr. Sugata Mitra's 2013 TED award talk, here is my effort to build a school in cloud. This is for my kids and other millions kids whose desires to learn were restricted by their financial difficulties.

Dr. Mitra asked, what did the poor do wrong ? let's answer it!

Datomic server configuration

When starting datomic, bin/transactor will print the URI for connecting, datomic🆓//localhost:4334/, means using free protocol. These are configured at free-transactor-template.properties. mainly set data and log dir and disable using ssl between peers and transactors. To create a connection string, simply replace DB-NAME with your db name.

db-uri = "datomic:sql://colorcloud?jdbc:mysql://localhost:3306/datomic?user=datomic&password=datomic";

lein datomic start &      # start datomic server first
lein datomic initialize   # load data specified in project.clj datomic schemas.
lein run create-schema    # create schema
lein run list-schema      # list all attributes in db
lein run add-family       # run 2 times to add 2 family
lein run create-homework  # run many times to create tons of homework
lein run create-assignment
lein run find-assignment  # get the assignment id and child id
lein run submit-answer assignment-id child-id 
lein run fake-comment     # fake a comment for testing
lein run create-course-lecture  # create a course and a list of lecture

Datomic database is persistence across restarts. To clean up databases, use (d/delete-database uri) (d/create-database uri). You can use repl to verify database is initialized properly. Note datomic db schema, config and db-uri are defined inside project.clj.

lein repl
(require '[datomic.api :as d])
(def uri "datomic:sql://colorcloud?jdbc:mysql://localhost:3306/datomic?user=datomic&password=datomic")
(def conn (d/connect uri))
(def db (d/db conn))
(d/delete-database uri)
(d/create-database uri)

(def results (q '[:find ?c :where [?c :community/name]] db))
results
(d/delete-database uri)
(d/create-database uri)

(d/q '[:find ?atn :where [?ref ?attr] [?attr :db/ident ?atn]] db)

or bin/shell uri = "datomic:sql://colorcloud?jdbc:mysql://localhost:3306/datomic?user=datomic&password=datomic"; conn = Peer.connect(uri); db = conn.db(); Peer.q("[:find ?p :where [?p :parent/child]]", db);

Sync between GrowingTrees App

As colorcloud db is the back-end for GrowingTrees, we share most of datomic data accessor code. We make modification inside growingtree-server namespace and copy the datomic folder to here. We subs growingtree-server namespace keyword to colorcloud before we can use it.

for f in *; do sed -i "" 's/growingtree-server/colorcloud/g' $f ; done;

Copyright

All copyright reserved by the author !