Add s3 support, fix bug with chrome.go, fix readme curl example.

[mdanzinger]

Hey! Sorry for the delay in getting the PR your way. I've added an s3Object which implements your StoredFile interface. I've used a singleton pattern to ensure we're not creating new s3 clients on every new s3Object creation.

Code can probably be cleaned up / simplified - looking forward to whatever feedback you may have!

Thanks!

[vjiandani-r7]

Looks good! Thanks for this. I'll wait until you give me the thumbs up to do a quick test locally. Assuming all is well, I'll approve/merge.

[mdanzinger]

Thanks for taking the time to review this. I'll be implementing your changes this weekend.

[mdanzinger]

@vjiandani-r7 Pushed changes as per your feedback.

[vjiandani-r7]

@mdanzinger I noticed a couple more things.

[mdanzinger]

Hey @vjiandani-r7, I've gone ahead and implemented your changes.

[vjiandani-r7]

I'm getting an error when trying to render a pdf: Failed to render: https://google.com\n Error: cdp.Target: CreateBrowserContext: rpc error: Not allowed. (code = -32000) Looking but if you know, let me know.

[mdanzinger]

@vjiandani-r7 That was the error I was receiving too, commit 67acb56 seemed to have fixed it for me. Are you running an updated version of chrome?

[vjiandani-r7]

I figured that one out. My bad on how I had things set up. I am running into the following issue while running the unit tests though:

go test -v ./...
?   	github.com/rapid7/pdf-renderer	[no test files]
?   	github.com/rapid7/pdf-renderer/cfg	[no test files]
?   	github.com/rapid7/pdf-renderer/correlation	[no test files]
?   	github.com/rapid7/pdf-renderer/renderer	[no test files]
=== RUN   TestNewS3Client
time="2019-02-19T12:50:55-08:00" level=error msg="MissingRegion: could not find region configuration"
MissingRegion: could not find region configuration
--- FAIL: TestNewS3Client (0.00s)
=== RUN   TestNewS3Object
time="2019-02-19T12:50:55-08:00" level=error msg="MissingRegion: could not find region configuration"
MissingRegion: could not find region configuration
--- FAIL: TestNewS3Object (0.00s)
panic: runtime error: invalid memory address or nil pointer dereference [recovered]
	panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x13caa57]

goroutine 6 [running]:
testing.tRunner.func1(0xc4201cc1e0)
	/usr/local/Cellar/go/1.10.3/libexec/src/testing/testing.go:742 +0x29d
panic(0x1438fa0, 0x1777c20)
	/usr/local/Cellar/go/1.10.3/libexec/src/runtime/panic.go:502 +0x229
github.com/rapid7/pdf-renderer/storage.(*s3Object).Write(0x0, 0xc42001eea0, 0x11, 0x20, 0x11, 0x20)
	/r7/src/go-projects/src/github.com/rapid7/pdf-renderer/storage/s3.go:105 +0x47
github.com/rapid7/pdf-renderer/storage.TestNewS3Object(0xc4201cc1e0)
	/r7/src/go-projects/src/github.com/rapid7/pdf-renderer/storage/s3__test.go:25 +0xfa
testing.tRunner(0xc4201cc1e0, 0x14e71d0)
	/usr/local/Cellar/go/1.10.3/libexec/src/testing/testing.go:777 +0xd0
created by testing.(*T).Run
	/usr/local/Cellar/go/1.10.3/libexec/src/testing/testing.go:824 +0x2e0
FAIL	github.com/rapid7/pdf-renderer/storage	0.075s
?   	github.com/rapid7/pdf-renderer/web	[no test files]
make: *** [test] Error 1

[mdanzinger]

Do you have a region set in the ~/.aws/credentials file?

region = us-east-2

[vjiandani-r7]

Ok I think this is fine. I'll probably want to add support for https://docs.aws.amazon.com/sdk-for-go/api/aws/ec2metadata/ though. Unless you would like to do that.