df202d6ef4
Replaces our current host-based HTTP healthchecks with Docker healthchecks, and adds a new `healthcheck.cmd` config option that can be used to define a custom health check command. Also removes Traefik's healthchecks, since they are no longer necessary. When deploying a container that has a healthcheck defined, we wait for it to report a healthy status before stopping the old container that it replaces. Containers that don't have a healthcheck defined continue to wait for `MRSK.config.readiness_delay`. There are some pros and cons to using Docker healthchecks rather than checking from the host. The main advantages are: - Supports non-HTTP checks, and app-specific check scripts provided by a container. - When booting a container, allows MRSK to wait for a container to be healthy before shutting down the old container it replaces. This should be safer than relying on a timeout. - Containers with healthchecks won't be active in Traefik until they reach a healthy state, which prevents any traffic from being routed to them before they are ready. The main _disadvantage_ is that containers are now required to provide some way to check their health. Our default check assumes that `curl` is available in the container which, while common, won't always be the case.
57 lines
1.3 KiB
Ruby
57 lines
1.3 KiB
Ruby
module Mrsk::Commands
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class Base
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delegate :sensitive, :argumentize, to: Mrsk::Utils
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DOCKER_HEALTH_STATUS_FORMAT = "'{{if .State.Health}}{{.State.Health.Status}}{{else}}{{.State.Status}}{{end}}'"
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attr_accessor :config
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def initialize(config)
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@config = config
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end
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def run_over_ssh(*command, host:)
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"ssh".tap do |cmd|
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cmd << " -J #{config.ssh_proxy.jump_proxies}" if config.ssh_proxy
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cmd << " -t #{config.ssh_user}@#{host} '#{command.join(" ")}'"
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end
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end
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def container_id_for(container_name:)
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docker :container, :ls, "--all", "--filter", "name=^#{container_name}$", "--quiet"
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end
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private
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def combine(*commands, by: "&&")
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commands
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.compact
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.collect { |command| Array(command) + [ by ] }.flatten # Join commands
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.tap { |commands| commands.pop } # Remove trailing combiner
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end
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def chain(*commands)
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combine *commands, by: ";"
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end
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def pipe(*commands)
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combine *commands, by: "|"
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end
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def append(*commands)
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combine *commands, by: ">>"
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end
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def write(*commands)
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combine *commands, by: ">"
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end
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def xargs(command)
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[ :xargs, command ].flatten
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end
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def docker(*args)
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args.compact.unshift :docker
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end
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end
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end
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