Faaso deploy command

TODO.md

@@ -31,7 +31,7 @@
 * ✅ Fix proxy reload / Make it reload on file changes
 * Implement `faaso help command`
 * Fix `export examples/hello_crystal` it has a `template/`
-* Implement zero-downtime rollout (`faaso deploy`)
+* ✅ Implement zero-downtime rollout (`faaso deploy`)
 * Cleanup `tmp/` after use unless `DEBUG` is set
 
 # Things to do but not before release

src/commands/deploy.cr

@@ -0,0 +1,41 @@
+module Faaso
+  module Commands
+    struct Deploy
+      # FIXME: local only for now
+      def run(options, funko_name : String) : Int32
+        Log.info { "Deploying #{funko_name}" }
+        funko = Funko::Funko.from_names([funko_name])[0]
+        # Get scale, check for out-of-date containers
+        current_scale = funko.scale
+        latest_image = funko.latest_image
+        containers = funko.containers
+        out_of_date = containers.count { |container| container.image_id != latest_image }
+        Log.info { "Need to update #{out_of_date} containers" }
+        Log.info { "Scaling from #{current_scale} to #{current_scale + out_of_date}" }
+        # Increase scale to get enough up-to-date containers
+        new_containers = funko.scale(current_scale + out_of_date)
+
+        # Wait for them to be healthy
+        begin
+          funko.wait_for(current_scale + out_of_date, 120, healthy: true)
+        rescue ex : Exception
+          # Failed to start, rollback
+          Log.error(exception: ex) { "Failed to scale, rolling back" }
+          docker_api = Docr::API.new(Docr::Client.new)
+          new_containers.each do |container|
+            docker_api.containers.stop(container.id)
+            docker_api.containers.delete(container.id)
+          end
+          return 1
+        end
+
+        Log.info { "Scaling down to #{current_scale}" }
+        # Decrease scale to the desired amount
+        funko.scale(current_scale)
+        funko.wait_for(current_scale, 30)
+        Log.info { "Deployed #{funko_name}" }
+        0
+      end
+    end
+  end
+end

src/faaso.cr

@@ -1,4 +1,5 @@
 require "./commands/build.cr"
+require "./commands/deploy.cr"
 require "./commands/export.cr"
 require "./commands/login.cr"
 require "./commands/new.cr"

src/funko.cr

@@ -85,16 +85,18 @@ module Funko
     end
 
     # Set the number of running instances of this funko
-    def scale(new_scale : Int)
+    # Returns the list of IDs started or stopped
+    def scale(new_scale : Int) : Array(String)
       docker_api = Docr::API.new(Docr::Client.new)
       current_scale = self.scale
-      return if current_scale == new_scale
+      result = [] of String
+      return result if current_scale == new_scale
 
       Log.info { "Scaling #{name} from #{current_scale} to #{new_scale}" }
       if new_scale > current_scale
         (current_scale...new_scale).each {
           Log.info { "Adding instance" }
-          id = create_container
+          result << (id = create_container)
           start(id)
           sleep 0.1.seconds
         }
@@ -105,6 +107,7 @@ module Funko
         }.each { |container|
           Log.info { "Removing instance" }
           docker_api.containers.stop(container.@id)
+          result << container.@id
           current_scale -= 1
           break if current_scale == new_scale
           sleep 0.1.seconds
@@ -116,6 +119,8 @@ module Funko
         Log.info { "Pruning dead instance" }
         docker_api.containers.delete(container.@id)
       }
+
+      result
     end
 
     # Setup the target directory `path` with all the files needed
@@ -184,7 +189,7 @@ module Funko
       docker_api.containers.list(all: true).select { |container|
         container.@names.any?(&.starts_with?("/faaso-#{name}-")) &&
           container.@state == "running"
-      }
+      } || [] of Docr::Types::ContainerSummary
     end
 
     # A comprehensive status for the funko:
@@ -207,12 +212,26 @@ module Funko
       end
     end
 
-    # Wait up to `t` seconds for the funko to reach the requested `state`
+    # Wait up to `t` seconds for the funko to reach the desired scale
-    def wait_for(new_scale : Int, t)
+    # If `healthy` is true, it will wait for the container to be declared
+    # healthy by the healthcheck
+    def wait_for(new_scale : Int, t : Int, healthy : Bool = false)
+      docker_api = Docr::API.new(Docr::Client.new)
       channel = Channel(Nil).new
       spawn do
         loop do
-          channel.send(nil) if scale == new_scale
+          if healthy
+            channel.send(nil) if containers.count { |container|
+                                   begin
+                                     container = docker_api.containers.inspect(container.@id)
+                                     channel.send(nil) if !container.nil? && (container.state.health.status == "healthy")
+                                   rescue ex : Docr::Errors::DockerAPIError
+                                     Log.error { "#{ex}" } unless ex.status_code == 304 # This just happens
+                                   end
+                                 } == new_scale
+          else
+            channel.send(nil) if scale == new_scale
+          end
           sleep 0.2.seconds
         end
       end
@@ -221,7 +240,7 @@ module Funko
       when channel.receive
         Log.info { "Funko #{name} reached scale #{new_scale}" }
       when timeout(t.seconds)
-        Log.error { "Funko #{name} did not reach scale #{new_scale} in #{t} seconds" }
+        raise Exception.new("Funko #{name} did not reach scale #{new_scale} in #{t} seconds")
       end
     end
 

src/main.cr

@@ -42,6 +42,8 @@ status : Int32 = 0
 case ans
 when .fetch("build", false)
   status = Faaso::Commands::Build.new.run(ans, ans["FOLDER"].as(Array(String)))
+when .fetch("deploy", false)
+  status = Faaso::Commands::Deploy.new.run(ans, ans["FUNKO"].as(String))
 when .fetch("export", false)
   status = Faaso::Commands::Export.new.run(ans, ans["SOURCE"].as(String), ans["DESTINATION"].as(String))
 when .fetch("login", false)