Swarm support improvements

[jkozera]

Hi @timdaman,

I've made a few changes which were useful for setting up Docker Swarm checks. They are available at master...operasoftware:master and I thought it may be useful to upstream some of them.

Since I'm not sure what's your vision for future of check_docker, I thought I'd open an issue before making a PR.

The changes are:

1. Slight performance improvement when fetching containers statuses if the expected status is running. (61041d8)
2. Rework of check_docker to allow wildcard checks to pass if there's only one container matching the wildcard. This is useful in case of Swarm services, as mentioned in Thorough check of services #43 (comment) of issue Thorough check of services #43 when using '[stack]_[service].*' wildcards. (2b1fc15)
3. Check for nodes statuses in check_swarm.py. (92bbe13)
4. Small improvements to Swarm checks wordings. (211969f)
5. .json config file support for easier automated deployment of checks. (6b78496)

Please let me know if you think anything from the above would be useful for you, in which case I could prepare some PR.

[thatsk]

if we want to test this can you tell me what is procedure to check the current status will not check for swarm worker node

[thatsk]

root@test: ~# docker run -v /var/run/docker.sock:/var/run/docker.sock checkswarm:1.0 --swarm
CRITICAL: Node is not in a swarm
root@test: ~# docker info
Client:
 Debug Mode: false

Server:
 Containers: 5
  Running: 2
  Paused: 0
  Stopped: 3
 Images: 10
 Server Version: 19.03.3
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: active
  NodeID: 0bsch8gqddktk2y0li2xvytv1
  Is Manager: false
  Node Address: 10.173.96.253
  Manager Addresses:
   10.173.96.232:2377
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: b34a5c8af56e510852c35414db4c1f4fa6172339
 runc version: 3e425f80a8c931f88e6d94a8c831b9d5aa481657
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 3.10.0-957.27.2.el7.x86_64
 Operating System: CentOS Linux 7 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 4
 Total Memory: 15.51GiB
 Name: ingca01p1.infra.smf1.mobitv
 ID: LPBT:YDOY:R43D:GOYY:B25E:THWH:I7U4:BVY6:FPRD:VZQW:ASGO:LVBB
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  harbor.infra.smf1.mobitv
  127.0.0.0/8
 Live Restore Enabled: false```