fibonacci

README

fibonacci

fibonacci (docker) Author: David Gnabasik Date: June 2, 2021. Task: Expose a Fibonacci sequence generator through a web API that memoizes intermediate values.

Semi-Automated Installation:: See ./install_fibonacci.sh mkdir -p ~/github.com/dgnabasik && cd ~/github.com/dgnabasik git clone https://github.com/dgnabasik/fibonacci cd fibonacci && pwd docker-compose up --build "Do not forget to first disable any local instances of Postgres with: sudo systemctl stop postgresql@12-main.service" "Open another terminal and execute: cd ~/github.com/dgnabasik/fibonacci && ./migration.sh " "Execute the curl commands in README.md or open a browser to the web addresses in README.md." "Press ctrl-C to stop the server. Execute ./cleanDocker.sh to remove the docker containers."

Manual Client Installation:: (a) mkdir ~/github.com/dgnabasik && cd ~/github.com/dgnabasik && git clone https://github.com/dgnabasik/fibonacci (b) Run tests from a terminal prompt with: cd ~/github.com/dgnabasik/fibonacci && cat fib.env && source fib.env && export NODE_ENV=development && go test -v if not running, start the local Postgres server with: sudo systemctl start postgresql@12-main.service (c) Run the docker container with: docker-compose up --build (d) Wait for the message of: "LOG: database system is ready to accept connections." (d) Open a browser to enter API URLs or use the curl command.

The web API should expose operations to:: (a) fetch the Fibonacci number given an ordinal (e.g. Fib(11) == 89, Fib(12) == 144): (b) fetch the number of memoized results less than a given value (e.g. there are 12 intermediate results less than 120). No, there are 11. (c) clear the data store.

Non-Docker Development URL Examples:: (a) http://localhost:5000/fib/clear ==> ClearDataStore: true (b) http://localhost:5000/fib/10 ==> Fibonacci: 55 (c) http://localhost:5000/fib/upper/120 ==> NumberMemoizedResults: 11

Docker URL Examples:: Or simply browse to the web address. (a) curl http://localhost:8080/fib/20 ==> Fibonacci: 6765 (b) curl http://localhost:8080/fib/upper/500 ==> NumberMemoizedResults: 14 (c) curl http://localhost:8080/fib/clear ==> ClearDataStore: true

Ubuntu 18.04 Development Environment:: (a) Docker (v20.10.6) & docker-compose (v1.26): Install from https://docs.docker.com/engine/install/ubuntu/ (b) Golang: v1.16.4 Install from https://golang.org/doc/install (c) Postgres v12.6+ Install from https://www.postgresql.org/download/ (d) golang-migrate Install from https://github.com/golang-migrate/migrate/tree/master/cmd/migrate migrate create -ext sql -dir migrations -seq create_fibonacci_table (e) Execute: docker-compose up --build (f) Execute: cd ~/github.com/dgnabasik/fibonacci && sudo ./migration.sh

Imported Go Packages:: (a) go get github.com/jackc/pgx/v4/pgxpool (b) go get github.com/gin-contrib/cors (c) go get github.com/gin-gonic/gin (d) github.com/jackc/pgx/v4 (e) github.com/jackc/pgx/v4/pgxpool

Environment Variables in fib.env:: (a) NODE_ENV: production or development. Change NODE_ENV to 'production' to run in docker container. (b) Postgres datatbase variables within Docker container. Change <> in FIB_DATABASE_URL to run local Postgres server.

Program Limitations:: (a) math.MaxFloat64 = 1.798e+308 // 21023 * (253 - 1) / 252 (b) math.MaxFloat32 = 3.4e+38 // 2127 * (224 - 1) / 223

Postgres Database Tables:: See migrations/000001_create_fibonacci_table.up.sql DROP TABLE IF EXISTS fibonacci; CREATE TABLE IF NOT EXISTS fibonacci ( id integer NOT NULL DEFAULT 0, fibvalue numeric(308,0), CONSTRAINT fibonacci_pkey PRIMARY KEY (id) ) WITH (OIDS=FALSE) TABLESPACE pg_default;

Git Commands:: echo "# fibonacci" >> README.md git init git add README.md git commit -m "first commit" git branch -M main git remote add origin https://github.com/dgnabasik/fibonacci.git git push -u origin main