Make S3 Key/Secret optional to allow support for "IAM role based access to s3 from EC2"

[BhautikDoshi]

IAM role based access to s3 from EC2 (instead of storing s3 key/secret)
http://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_use_switch-role-ec2.html

BTW, thanks for oc - trying it out for a big UI project mashing new/old UI coming from different projects/groups with version matrix. OC seems to be a great fit.

So to fix the s3 key/secret validation error during registry startup, I just had to remove the validation code by changing line 66 of oc/src/registry/domain/validators/registry-configuration.js
from:

if(!conf.s3 || !conf.s3.bucket || !conf.s3.key || !conf.s3.region || !conf.s3.secret){

to:

if(!conf.s3 || !conf.s3.bucket || !conf.s3.region ){

After the change, the oc-registry on EC2 comes up fine with just bucket name, region.
(The Javascript AWS SDK will pull the Key/Secret from EC2 instance using http://169.254.169.254/latest/metadata/iam/security-credentials/role-name - these key/secret are automatically rotated and SDK will refresh it - more secure than having to handle s3 credentials ourselves)

s3: {
bucket: '<BUCKET_NAME>',
region: 'us-east-1',
componentsDir: 'components'
},

Still new to the OC code and not very familiar yet. But if this above code change seems fine, let me know if you like me to post a PR. Thanks.

[matteofigus]

Hi @BhautikDoshi this is great, I actually wasn't aware of this.

If you could make a PR to make those properties optional as you recommend it would be awesome!

Also, thanks for your nice words about our work. Very glad to hear it is useful to you 👍

[BhautikDoshi]

Hi Matteo, I have pushed the PR. Ran tests successfully.
Look forward to contributing more as and when need arises to enhance OC for our use case which could benefit others.

[matteofigus]

Fixed with #337