A curated list of AWS resources to prepare for the AWS Certifications
A curated list of awesome AWS resources you need to prepare for the all 5 AWS Certifications. This gist will include: open source repos, blogs & blogposts, ebooks, PDF, whitepapers, video courses, free lecture, slides, sample test and many other resources.
Index:
State machines are everywhere in interactive systems, but they're rarely defined clearly and explicitly. Given some big blob of code including implicit state machines, which transitions are possible and under what conditions? What effects take place on what transitions?
There are existing design patterns for state machines, but all the patterns I've seen complect side effects with the structure of the state machine itself. Instances of these patterns are difficult to test without mocking, and they end up with more dependencies. Worse, the classic patterns compose poorly: hierarchical state machines are typically not straightforward extensions. The functional programming world has solutions, but they don't transpose neatly enough to be broadly usable in mainstream languages.
Here I present a composable pattern for pure state machiness with effects,
| #cribbed from http://vimeo.com/52569901 (Twilio carrier call origination moderation) | |
| # The idea is that many fan-in queues can enqueue at any rate, but | |
| # dequeue needs to happen in a rate-controlled manner without allowing | |
| # any individual input queue to starve other queues. | |
| # http://en.wikipedia.org/wiki/Leaky_bucket (second sense, "This version is referred to here as the leaky bucket as a queue.") | |
| # | |
| # requires: | |
| # redis 2.6+ | |
| # redis-py>=2.7.0 | |
| # anyjson |
| 00:48:34 <'wpool_pool-devapi_connection_worker-1'> {devapi_router, | |
| route_user_dir, | |
| [{get_user, | |
| "wMWGi39ZrWGVCTqJYe6Siyb1", | |
| "2a731b46-ed7e-4b84-86b3-bcb8a497e184", | |
| <<"57ca0933-b7f1-47f4-bf80-bf1d4483bf23">>}, | |
| {state}]} | |
| 00:48:35 <'wpool_pool-devapi_connection_worker-1'> devapi_router:route_user_dir/2 -> {ok, | |
| [{full_view, |
| type Item struct { | |
| Id int `json:"id" db:"id"` | |
| Maker string `json:"maker" db:"maker"` // komatsu, hitachi; fixed | |
| Model string `json:"model" db:"model"` // SK815; non unique | |
| Serial string `json:"serial" db:"serial"` // 37BF00l74; unique | |
| Kind string `json:"kind" db:"kind"` // forklift, loader, crane | |
| Year int `json:"year" db:"year"` // 1988 | |
| Description string `json:"description" db:"description"` |
| unsent_count(Config) -> | |
| Org = proplists:get_value(org, Config), | |
| ok = tt_devapi_test_utils:xmpp_call(tt_org_data, set_billing, [Org, "active"]), | |
| ok = tt_devapi_test_utils:xmpp_call(tt_pubsub_data, publish_organization, [Org]), | |
| User2 = proplists:get_value(token2, Config), | |
| User3 = proplists:get_value(token3, Config), | |
| Auth = {basic_auth, proplists:get_value(impersonate_auth, Config)}, |
| https://www.groupon.com/deals/sea-stallion-scuba-outfitters-6 | |
| $189, http://www.seastallion.com/ | |
| 21098 Bake Pkwy # 108, Lake Forest, CA 92630 | |
| two 4-hours classroom sessions, two 4-hour pool session | |
| 5 open water dives. certification upon passing exam | |
| https://www.groupon.com/deals/beach-cities-scuba-centers-2 | |
| 2 weekends. 1st: classrom session & wednesday night orientation | |
| 4 dives in open ocean from edge of boat / beach | |
| $239 for a semiprivate PADI Open Water Diver certification course (a $575 value) |
In a project I'm working on I ran into the requirement of having some sort of persistent FIFO buffer or pipe in Linux, i.e. something file-like that could accept writes from a process and persist it to disk until a second process reads (and acknowledges) it. The persistence should be both across process restarts as well as OS restarts.
AFAICT unfortunately in the Linux world such a primitive does not exist (named pipes/FIFOs do not persist
| ➜ personal2 dig http://www.starlite-creations.com/ | |
| ; <<>> DiG 9.8.3-P1 <<>> http://www.starlite-creations.com/ | |
| ;; global options: +cmd | |
| ;; Got answer: | |
| ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 30122 | |
| ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0 | |
| ;; QUESTION SECTION: | |
| ;http://www.starlite-creations.com/. IN A |
| -module(validation_utils). | |
| -export([validate_until_first_error/2]). | |
| -export([validate_all_errors/2]). | |
| -type validation_args() :: [term()]. | |
| -type validation_funs() :: [{function(), atom()}]. | |
| -spec validate_until_first_error(validation_args(), validation_funs()) -> ok | {error, atom()}. | |
| % validate_until_first_error/2 applies list of validation_funs() to each element in args |
