Support for SQL[ite]

[alixaxel]

I guess having at least one kind of SQL dialect implement would be a good addition.

I'm gonna try and submit a PR sometime soon for .sql > SQLite support.

[alixaxel]

Unfortunately I didn't had much time to learn how to create a new integration following dexec conventions.

I started with a simple Dockerfile:

FROM        ubuntu:14.04
MAINTAINER  alixaxel
ENV         LANG C.UTF-8
RUN         apt-get update -qq -y && \
            apt-get install -y sqlite3 && \
            apt-get clean
VOLUME      /tmp/dexec/build

And then:

docker build -t dexec/lang-sqlite .

To test it, I created a new file (HelloWorld.sql) with the following contents:

CREATE TABLE "primes" (
    "id" INTEGER NOT NULL,
    "is_prime" INTEGER NOT NULL DEFAULT (0)
);

INSERT INTO "primes" ("id", "is_prime") VALUES (1, 0);
INSERT INTO "primes" ("id", "is_prime") VALUES (2, 1);
INSERT INTO "primes" ("id", "is_prime") VALUES (3, 1);
INSERT INTO "primes" ("id", "is_prime") VALUES (4, 0);
INSERT INTO "primes" ("id", "is_prime") VALUES (5, 1);
INSERT INTO "primes" ("id", "is_prime") VALUES (6, 0);
INSERT INTO "primes" ("id", "is_prime") VALUES (7, 1);
INSERT INTO "primes" ("id", "is_prime") VALUES (8, 0);
INSERT INTO "primes" ("id", "is_prime") VALUES (9, 0);

SELECT 'Hello World!';
SELECT COUNT(1) FROM "primes" WHERE "is_prime" = 0;
SELECT COUNT(1) FROM "primes" WHERE "is_prime" = 1;

And executed it directly with the containers SQLite 3 binary:

docker run --rm -v $(pwd -P)/HelloWorld.sql:/tmp/dexec/build/HelloWorld.sql \
    dexec/lang-sqlite sqlite3 \
        --init /tmp/dexec/build/HelloWorld.sql

It's also possible to "annex" additional query commands within the context of the SQL file:

docker run --rm -v $(pwd -P)/HelloWorld.sql:/tmp/dexec/build/HelloWorld.sql \
    dexec/lang-sqlite sqlite3 \
        --init /tmp/dexec/build/HelloWorld.sql \
        --cmd 'SELECT SUM("id") FROM "primes" WHERE "is_prime" = 1;'

The output of that being:

Hello World!
5
4
17

@andystanton Could you give some guidance on how to integrate additional languages?