[extension/ecsobserver] Add task definition, ec2 and service fetcher

[pingleig]

Description:

• get ECS task definition
• get EC2 instance if it's ECS EC2
• get ECS service and map them to tasks

Most code is in the mock and they looks very similar. Not sure if there is a better way when it comes to generating mock data of specific struct(s) in a for loop.

Link to tracking Issue:

• Feature request [Feature Request] [Extension] ECS Service Discovery for Prometheus #1395

Pending PRs

• Service matcher [extension/ecsobserver] Add service and task definition based matcher #3386
• Exporter [extension/ecsobserver] Add exporter to convert task to target #3333

Previous PRs

• Fetch Task [extension/ecsobserver] Init service client and mock #3284
• Docker Label Matcher [extension/ecsobserver] Add docker label based matcher #3276
• Task IP and Port [extension/ecsobserver] Add get ip and port from task #3133
• Target and Task definition (merged) [extension][ecsobserver] Init config and target definition #2939
• Config PR (merged) [extension][ecsobserver] Init ECS Observer README #2377
• Original PR (closed) [extension][ecsobserver] Init ECS service discovery using docker label #2734

Testing:

unit test

Documentation:

No new doc. See existing doc

[pingleig]

cc @Aneurysm9

hmm: it seems the bot picked Anuraag

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[mxiamxia]

LGTM

[anuraaga]

Is it ok for this not to be atomic? Does the LRU have some sort of construct like computeIfAbsent?

[pingleig]

There is only single go routine running, so there is no concurrent access to the LRU cache. The cache is not go routine safe but its only callback is onEvict and we are not using it.

Old code to show how the fetcher get called by a single ticker

[Aneurysm9]

Please ensure the dependencies are up-to-date:

diff --git a/receiver/awscontainerinsightreceiver/go.mod b/receiver/awscontainerinsightreceiver/go.mod
index a13801999..1a7ca5ea1 100644
--- a/receiver/awscontainerinsightreceiver/go.mod
+++ b/receiver/awscontainerinsightreceiver/go.mod
@@ -3,9 +3,9 @@ module github.com/open-telemetry/opentelemetry-collector-contrib/receiver/awscon
 go 1.16
 
 require (
-	github.com/aws/aws-sdk-go v1.38.51
+	github.com/aws/aws-sdk-go v1.38.55
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/aws/awsutil v0.0.0-00010101000000-000000000000
-	github.com/shirou/gopsutil v3.21.4+incompatible
+	github.com/shirou/gopsutil v3.21.5+incompatible
 	github.com/stretchr/testify v1.7.0
 	go.opentelemetry.io/collector v0.27.1-0.20210603182316-5369d7e9e83e
 	go.uber.org/zap v1.17.0
Generated code is out of date, please run "make generate" and commit the changes in this PR.

Exited with code exit status 1

[pingleig]

The dependency error should be fixed by #3735 I think unit test and lint are breaking for all PRs now.

I will rebase after the fix is merged.

[bogdandrutu]

Fix is merged please rebase

[pingleig]

@bogdandrutu rebased, thx.

btw: #3333 is also ready to merge.