Class: Kamal::Configuration::Loadbalancer

Inherits:
Proxy
  • Object
show all
Defined in:
lib/kamal/configuration/loadbalancer.rb

Constant Summary collapse

CONTAINER_NAME = 
"load-balancer".freeze
SHARED_CONTAINER_NAME = 
"kamal-proxy".freeze

Constants inherited from Proxy

Proxy::CLIENT_CA_FILENAME, Proxy::COMPRESSION_ENCODING_ALIASES, Proxy::DEFAULT_COMPRESSION_ENCODINGS, Proxy::DEFAULT_LOG_REQUEST_HEADERS, Proxy::DEPLOY_OPTION_DISPOSITIONS, Proxy::LOADBALANCER_CONTAINER_NAME, Proxy::SUPPORTED_COMPRESSION_ENCODINGS

Instance Attribute Summary

Attributes inherited from Proxy

#config, #proxy_config, #role_name, #secrets

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Proxy

#all_deploy_options, #app_port, #certificate_pem_content, #client_ca?, #client_ca_pem, #client_ca_pem_content, #container_client_ca, #container_tls_cert, #container_tls_key, #custom_ssl_certificate?, #deploy_options, disposition, #effective_loadbalancer, #healthcheck_path, #host_client_ca, #host_tls_cert, #host_tls_key, #hosts, #load_balanced?, #load_balancing?, #loadbalancer, #loadbalancer_on_proxy_host?, #merge, #on_demand_url, #path_prefixes, #private_key_pem_content, #reboot_on_deploy?, #rollout_deploy_command_args, #rollout_deploy_options, #rollout_set_command_args, #ssl?, #ssl_config, #stop_command_args, #stop_options

Methods included from Validation

#validate!, #validation_yml

Constructor Details

#initialize(config:, proxy_config:, secrets:) ⇒ Loadbalancer

Returns a new instance of Loadbalancer.



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# File 'lib/kamal/configuration/loadbalancer.rb', line 9

def initialize(config:, proxy_config:, secrets:)
  super
end

Class Method Details

.validation_config_key ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 5

def self.validation_config_key
  "proxy"
end

Instance Method Details

#container_name ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 92

def container_name
  on_proxy_host? ? SHARED_CONTAINER_NAME : CONTAINER_NAME
end

#deploy_command_args(targets:) ⇒ Object

The load balancer fans a single service out to many targets, so unlike the per-app proxy deploy (which takes one target) it takes the full list and joins them into a single --target flag.

Each target is a per-host proxy, reached on its published HTTP port (run.http_port, default 80) - the only cross-host surface it exposes. Never app_port: that is how a per-host proxy reaches the app container inside its own docker network, and nothing listens on it across hosts.



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# File 'lib/kamal/configuration/loadbalancer.rb', line 21

def deploy_command_args(targets:)
  target_arg = targets.map { |target| "#{target}:#{run.http_port}" }.join(",")
  optionize ({ target: target_arg }).merge(deploy_options), with: "="
end

#directory ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 33

def directory
  File.join config.run_directory, "loadbalancer"
end

#on_proxy_host? ⇒ Boolean

When loadbalancer is on a proxy host, it takes over the proxy role

Returns:

  • (Boolean) 


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# File 'lib/kamal/configuration/loadbalancer.rb', line 97

def on_proxy_host?
  config.proxy_hosts.include?(config.proxy.effective_loadbalancer)
end

#owner_token ⇒ Object

Kamal has no app identifier, so ownership of a service on a shared load balancer is expressed as repository plus destination-qualified service name: the repository separates two different apps, the destination separates two deployments of one app. The load balancer registers services under the bare service name, so both can collide.



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# File 'lib/kamal/configuration/loadbalancer.rb', line 72

def owner_token
  [ config.service_and_destination, config.repository ].join(" ")
end

#run ⇒ Object

The load balancer is a kamal-proxy container, so proxy/run applies to it exactly as it does to the per-host proxies. Without a run block it still needs the default surface (published ports, log rotation, the apps-config mount and the run command) to boot from, so fall back to an empty config rather than to nil.



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# File 'lib/kamal/configuration/loadbalancer.rb', line 42

def run
  @run ||= Kamal::Configuration::Proxy::Run.new(config, run_config: {})
end

#run_args ⇒ Object

Docker options for the load balancer container: publish/logging/options plus the mounts and env file the proxy's run surface brings along — notably the secrets env file, without which the edge cannot issue certificates even though it is the layer terminating TLS.

The one holder-mode exception: port_holder suppresses publish_args on the proxy hosts (the holder owns the ports there), but the load balancer has no holder — its reboot path is stop->run — so it always publishes its own.



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# File 'lib/kamal/configuration/loadbalancer.rb', line 54

def run_args
  [ *(run.publish_args if run.port_holder?), *run.docker_options_args ]
end

#run_config_digest ⇒ Object

Digest of what the load balancer container is booted with, so a second app pointing at the same host can tell whether its proxy/run agrees with whatever is already running there. Same composition as the proxy's own drift digest: image, run command, docker options and the acme credential names (their values deliberately stay out - see Proxy::Run#config_digest).



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# File 'lib/kamal/configuration/loadbalancer.rb', line 63

def run_config_digest
  run.config_digest
end

#run_config_file ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 80

def run_config_file
  File.join directory, "run_config"
end

#run_config_record ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 76

def run_config_record
  [ owner_token, run_config_digest ].join(" ")
end

#service_owner_file ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 88

def service_owner_file
  File.join services_directory, config.service
end

#services_directory ⇒ Object 



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# File 'lib/kamal/configuration/loadbalancer.rb', line 84

def services_directory
  File.join directory, "services"
end

#target_hosts ⇒ Object

The hosts the load balancer forwards to: every host of every role that runs a proxy. One source of truth for the deploy step and the reboot re-registration, so their target lists cannot diverge.



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# File 'lib/kamal/configuration/loadbalancer.rb', line 29

def target_hosts
  config.roles.select(&:running_proxy?).flat_map(&:hosts)
end