This gem determines which files need to be added, updated and optionally deleted and only transfer these files up. This reduces the impact of an update on a web site hosted on S3.
Middleman Sync does a great job to push Middleman generated websites to S3. The only issue I have with it is that it pushes every files under build to S3 and doesn't seem to properly delete files that are no longer needed.
Add this line to your application's Gemfile:
gem 'middleman-s3_sync'
And then execute:
$ bundle
Or install it yourself as:
$ gem install middleman-s3_sync
You need to add the following code to your config.rb
file:
activate :s3_sync do |s3_sync|
s3_sync.bucket = 'my.bucket.com' # The name of the S3 bucket you are targeting. This is globally unique.
s3_sync.region = 'us-west-1' # The AWS region for your bucket.
s3_sync.aws_access_key_id = 'AWS KEY ID'
s3_sync.aws_secret_access_key = 'AWS SECRET KEY'
s3_sync.delete = false # We delete stray files by default.
s3_sync.after_build = false # We do not chain after the build step by default.
s3_sync.prefer_gzip = true
s3_sync.path_style = true
s3_sync.reduced_redundancy_storage = false
s3_sync.acl = 'public-read'
s3_sync.encryption = false
s3_sync.prefix = ''
s3_sync.version_bucket = false
s3_sync.index_document = 'index.html'
s3_sync.error_document = '404.html'
end
You can then start synchronizing files with S3 through middleman s3_sync
.
The following defaults apply to the configuration items:
Setting | Default |
---|---|
aws_access_key_id | - |
aws_secret_access_key | - |
bucket | - |
delete | true |
after_build | false |
prefer_gzip | true |
reduced_redundancy_storage | false |
path_style | true |
encryption | false |
acl | 'public-read' |
version_bucket | false |
There are several ways to provide the AWS credentials for s3_sync:
config.rb
You can set the aws_access_key_id and aws_secret_access_key in the block that is passed to the activate method.
I strongly discourage using this method. This will lead you to add and commit these changes to your SCM and potentially expose sensitive information to the world.
.s3_sync
FileYou can create a .s3_sync
at the root of your middleman project.
The credentials are passed in the YAML format. The keys match the
options keys.
The .s3_sync file takes precedence to the configuration passed in the activate method.
A sample .s3_sync
file is included at the root of this repo.
Make sure to add .s3_sync to your ignore list if you choose this approach. Not doing so may expose credentials to the world.
The aws credentials can also be passed via a command line options
--aws_access_key_id
(-k
) and --aws_secret_access_key
(-s
). They should override
any other settings if specified.
You can also pass the credentials through environment variables. They map to the following values:
Setting | Environment Variable |
---|---|
aws_access_key_id | ENV['AWS_ACCESS_KEY_ID'] |
aws_secret_access_key | ENV['AWS_SECRET_ACCESS_KEY'] |
bucket | ENV['AWS_BUCKET'] |
The environment is used when the credentials are not set in the activate
method or passed through the .s3_sync
configuration file.
Alternatively, if you are running builds on EC2 instance which has approrpiate IAM role, then you don't need to think about specifying credentials at all – they will be pulled from AWS metadata service.
Here's a sample IAM policy that will allow a user to update the site contained in a bucket named "mysite.com":
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": "s3:*",
"Resource": "arn:aws:s3:::mysite.com"
},
{
"Effect": "Allow",
"Action": "s3:*",
"Resource": "arn:aws:s3:::mysite.com/*"
}
]
}
This will give full access to both the bucket and it's contents.
There are situations where you might need to push the files to S3. In
such case, you can pass the --force
(-f
) option:
$ middleman s3_sync --force
You can override the destination bucket using the --bucket
(-b
) switch.
The command is:
$ middleman s3_sync --bucket=my.new.bucket
You can override the destination prefix using the --prefix
(-p
) switch. The
command is:
$ middleman s3_sync --prefix=my/new/prefix
You can specify which environment to run Middleman under using the
--environment
(-e
) option:
$ middleman s3_sync --environment=production
You can set up separate sync environments in config.rb like this:
configure :staging do
activate :s3_sync do |s3_sync|
s3_sync.bucket = '<bucket'
...
end
end
See the Usage section above for all the s3_sync. options to include. Currently, the .s3_sync file does not allow separate environments.
You can perform a dry run to see what would be the result of a sync
operation using the --dry_run
(-d
) option:
$ middleman s3_sync --dry_run
The --instrument
(-i
) option will output more information about Middleman
and s3_sync.
The --build
(-B
) option will ensure that Middleman build is run before the
synchronization with the S3 bucket.
You can push to a folder within an S3 bucket by adding using the prefix option in the config block:
activate :s3_sync do |s3_sync|
# ...
s3_sync.prefix = 'prefix'
end
You can enable bucket versioning by setting the version_bucket
setting to true within the bucket configuration.
Versioning is enabled at the bucket level, not at the object level.
You can find out more about versioning here.
By default, middleman-s3_sync
does not set caching headers. In
general, the default settings are sufficient. However, there are
situations where you might want to set a different HTTP caching policy.
This may be very helpful if you are using the asset_hash
extension.
You can set a caching policy for every files that match a certain mime-type. For example, setting max-age to 0 and kindly asking the browser to revalidate the content for HTML files would take the following form:
caching_policy 'text/html', max_age: 0, must_revalidate: true
As a result, the following Cache-Control
header would be set to max-age:0, must-revalidate
You can set the default policy by passing an options hash to default_caching_policy
in your config.rb
file after the activate :s3_sync ... end
block:
default_caching_policy max_age:(60 * 60 * 24 * 365)
This will apply the policy to any file that do not have a mime-type specific policy.
The Caching Tutorial is a great introduction to HTTP caching. The caching policy code in this gem is based on it.
The following keys can be set:
Key | Value | Header | Description |
---|---|---|---|
max_age |
seconds | max-age |
Specifies the maximum amount of time that a representation will be considered fresh. This value is relative to the time of the request |
s_maxage |
seconds | s-maxage |
Only applies to shared (proxies) caches |
public |
boolean | public |
Marks authenticated responses as cacheable. |
private |
boolean | private |
Allows caches that are specific to one user to store the response. Shared caches (proxies) may not. |
no_cache |
boolean | no-cache |
Forces caches to submit the request to the origin server for validation before releasing a cached copy, every time. |
no_store |
boolean | no-store |
Instructs caches not to keep a copy of the representation under any conditions. |
must_revalidate |
boolean | must-revalidate |
Tells the caches that they must obey any freshness information you give them about a representation. |
proxy_revalidate |
boolean | proxy-revalidate |
Similar as must-revalidate , but only for proxies. |
Expires
HeaderYou can pass the expires
key to the caching_policy
and
default_caching_policy
methods if you insist on setting the expires
header on a results. You will need to pass it a Time object indicating
when the resource is set to expire.
Note that the
Cache-Control
header will take precedence over theExpires
header if both are present.
Browser caching is well specified. It hasn't always been the case.
Still, even modern browsers have different behaviors if it suits it's
developers or their employers. Specs are meant to be ignored and so they
are (I'm looking at you Chrome!). Setting the Cache-Control
or
Expires
headers are not a guarrantie that the browsers and the proxies
that stand between them and your content will behave the way you want
them to. YMMV.
You can now set the content type of a path through the
s3_sync.content_types
hash. This hasi will take precendence over
the content type discovered by the mime_types gem. The associated pull
request has a
few good examples on how to use this feature.
middleman-s3_sync
will set the resources's ACL to public-read
by default. You
can specificy a different ACL via the acl
configuration option.
The valid values are:
private
public-read
public-read-write
authenticated-read
bucket-owner-read
bucket-owner-full-control
The full values and their semantics are documented on AWS's documentation site.
You can ask Amazon to encrypt your files at rest by setting the
encryption
option to true. Server side encryption is documented
on the AWS documentation
site
.
You can set the prefer_gzip
option to look for a gzipped version
of a resource. The gzipped version of the resource will be pushed to S3
instead of the original and the Content-Encoding
and Content-Type
headers will be set correctly. This will cause Amazon to serve the
compressed version of the resource. In order for this to work, you need to
have the :gzip
extension activated in your config.rb
.
You can enable a custom index document
and error document
settings. The index_document
option tells which file name gets used as
the index document of a directory (typically, index.html
), while
error_document
specifies the document to display for 4xx errors (ie,
the 404 page).
I used Middleman Sync as a template for building a Middleman extension. The code is well structured and easy to understand and it was easy to extend it to add my synchronization code. My gratitude goes to @karlfreeman and his work on Middleman sync.
Many thanks to Gnip and dojo4 for supporting and sponsoring work on middleman-s3_sync.
git checkout -b my-new-feature
)git commit -am 'Add some feature'
)git push origin my-new-feature
)