Saturday, August 19, 2017

stuff an app into a docker image

I had some fun over the last week setting up a docker image for an S3-copy utility, and integrating it into the gulp build for I pushed the image for the s3cp app up to I use s3cp to sync a local build of up to an S3 bucket. I could probably coerce the AWS CLI (aws s3 sync) into doing the same job, but I wrote this app a while ago, and it includes functionality to automatically gzip-compress each asset before upload, and setup various HTTP headers on the asset (content-encoding, cache-control, content-type, and etag). For example - inspect the headers (using a browser's developer tools) on an arbitrary asset like

A few s3cp details - it's a simple scala application with two command line flags (-config aws-key aws-secret, -copy source destination). The '-config' command saves the AWS credential under ~/.littleware/aws/. The code could use a little love - it is hard-coded to use the AWS Virginia region, it could use a '-force' option with '-copy', and its error messages are annoying - but it works for what I need. The source is on github (git clone ...; cd littleware/webapp/littleApps/s3Copy; gradle build; gradle copyToLib; cli/ --help).

I pushed a binary build of s3cp to dockerhub. I run it like this. First, I register my AWS credentials with the app. We only need to configure s3cp once, but we'll want to mount a docker volume to save the configuration to (I need to wire up a more secure way to save and pass the AWS secrets):

docker volume create littleware

docker run -it -v littleware:/root/.littleware \
    -v /home/reuben:/mnt/reuben \
    --name s3cp --rm frickjack/s3cp:1.0.0 \
    -config aws-key aws-secret

After the configuration is done I use s3cp with '-copy' commands like this:

docker run -it -v littleware:/root/.littleware \
    -v /home/reuben:/mnt/reuben \
    --name s3cp --rm frickjack/s3cp:1.0.0 \
    -copy /mnt/reuben/Code/littleware-html5Client/build/ s3://

I added a gulp task to the code to simplify the S3 deploy - from gulpfile.js:

gulp.task( 'deploy', [ 'compileclean' ], function(cb) {
    const pwdPath = process.cwd();
    const imageName = "frickjack/s3cp:1.0.0";
    const commandStr = "yes | docker run --rm --name s3gulp -v littleware:/root/.littleware -v '" +
        pwdPath + ":/mnt/workspace' " + imageName + " -copy /mnt/workspace/build/ s3://";

    console.log( "Running: " + commandStr );

    exec( commandStr, 
        function (err, stdout, stderr) {
            if ( err ) {
                //reject( err );
            } else {
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