favila

(require '[datomic.api :as d])

(d/create-database "datomic:mem://counter-example")
;=> true
(def c (d/connect "datomic:mem://counter-example"))
;=> #'user/c

;; The essential features of creating and using an auto-increment counter in datomic:
;;
;; 1. A counter entity must store the current value and a nonce.

favila

-- Optimized MYSQL schema for datomic
-- Unfortunately the bin/sql/mysql-*.sql bootstrapping files for datomic are not
-- very good, and can actually cause failures if not adjusted.
-- One symptom of this is the following error:

-- SQL Error (1071): Specified key was too long; max key length is 767 bytes.

-- Reported here: https://support.cognitect.com/entries/28462168-MySQL-Caveats

-- This is caused by the default collation for the `id` column possibly being

favila

#! /bin/sh
# Produce a squash-commit patch from a branch of changes
MASTER=$1
PATCHBRANCH=$2
SQUASHBRANCH="$PATCHBRANCH-squash"
MESSAGE=$3

git checkout -b $SQUASHBRANCH $MASTER &&
git merge --squash $PATCHBRANCH &&
git commit -a -m "$MESSAGE" &&

favila

(ns favila.eid-utils
  "Utilities to construct or decompose entity ids on on-prem systems.

  Many of these utilities replicate datomic.api functions because the peer api
  lacks them.

  The entity id format is:

      sign-bit, reserved-bit, 20-partition-bits, 42-t-bits

favila

(require '[datomic.api :as d])
(defn last-touched-tx
  "Return the tx of the oldest assertion on `entity` or any of its components."
  [db entity]
  (or (d/q '[:find (max ?tx) .
             :in $ % ?root
             :where
             (component-entities ?root ?ce)
             (union ?root ?ce ?e)
             [?e _ _ ?tx]]

favila

(defn safe-merge
  "Like merge, but throws if maps have the same keys but different values."
  [& maps]
  (reduce
   (fn [m [m2k m2v :as re]]
     (if-some [[_ mv :as le] (find m m2k)]
       (if (= mv m2v)
         m
         (throw (ex-info "Attempted to safe-merge maps with conflicting entries"

favila

#!/bin/sh

# Uses the h2 jar in a datomic distribution to give raw SQL access
# to the h2 database datomic "dev" storage uses.
# The 'SHUTDOWN COMPACT' command in particular performs all
# vaccum-like compaction of the h2 database file to remove
# unused blocks from deleted (garbage-collected) segments.

DATOMIC_HOME=${DATOMIC:-$HOME/lib/datomic/current}
DATOMIC_ADMIN_PASSWORD=${1:?Storage admin password must be provided}

favila

(ns favila.read-edn.tag-readers
  "Common tag-reader maps for edn."
  (:require datomic.db
            datomic.function
            datomic.codec)
  (:import java.net.URI))

(defmethod print-method URI [^URI x ^Writer w]
  (doto w
    (.write "#uri ")

favila

(ns kafka-workbench
  (:require [franzy.clients.consumer.protocols :as c]
            [franzy.clients.producer.protocols :as p]
            [franzy.serialization.serializers :as serializers]
            [franzy.serialization.deserializers :as deserializers]
            [franzy.clients.consumer.client :as consumer]
            [franzy.clients.producer.client :as producer]))

(def kafka-brokers [])

favila

(defn tx-pipeline-inorder
  "Transact transactions in core.async channel `from-ch` against datomic connection `conn` with a pipeline depth of `n`.
  
  Returns a map with keys `:stop!` and `:result`. `:stop!` is a no-arg function you can call to immediately
  cease sending transactions (already sent transactions cannot be stopped). `:result` is a promise channel
  returning a variant of the result of the tx-pipelining after from-ch is closed and drained, or
  :stop! is called and all send transaction futures are deref-ed, or a transaction produces an exception.
  
  The variant returned from the :result channel may be one of: