1 files changed, 90 insertions, 0 deletions
diff --git a/app/models/ci/build_trace_chunks/redis_base.rb b/app/models/ci/build_trace_chunks/redis_base.rb
new file mode 100644
index 00000000000..3b7a844d122
--- /dev/null
+++ b/app/models/ci/build_trace_chunks/redis_base.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+module Ci
+  module BuildTraceChunks
+    class RedisBase
+      CHUNK_REDIS_TTL = 1.week
+      LUA_APPEND_CHUNK = <<~EOS
+        local key, new_data, offset = KEYS[1], ARGV[1], ARGV[2]
+        local length = new_data:len()
+        local expire = #{CHUNK_REDIS_TTL.seconds}
+        local current_size = redis.call("strlen", key)
+        offset = tonumber(offset)
+
+        if offset == 0 then
+          -- overwrite everything
+          redis.call("set", key, new_data, "ex", expire)
+          return redis.call("strlen", key)
+        elseif offset > current_size then
+          -- offset range violation
+          return -1
+        elseif offset + length >= current_size then
+          -- efficiently append or overwrite and append
+          redis.call("expire", key, expire)
+          return redis.call("setrange", key, offset, new_data)
+        else
+          -- append and truncate
+          local current_data = redis.call("get", key)
+          new_data = current_data:sub(1, offset) .. new_data
+          redis.call("set", key, new_data, "ex", expire)
+          return redis.call("strlen", key)
+        end
+      EOS
+
+      def data(model)
+        with_redis do |redis|
+          redis.get(key(model))
+        end
+      end
+
+      def set_data(model, new_data)
+        with_redis do |redis|
+          redis.set(key(model), new_data, ex: CHUNK_REDIS_TTL)
+        end
+      end
+
+      def append_data(model, new_data, offset)
+        with_redis do |redis|
+          redis.eval(LUA_APPEND_CHUNK, keys: [key(model)], argv: [new_data, offset])
+        end
+      end
+
+      def size(model)
+        with_redis do |redis|
+          redis.strlen(key(model))
+        end
+      end
+
+      def delete_data(model)
+        delete_keys([[model.build_id, model.chunk_index]])
+      end
+
+      def keys(relation)
+        relation.pluck(:build_id, :chunk_index)
+      end
+
+      def delete_keys(keys)
+        return if keys.empty?
+
+        keys = keys.map { |key| key_raw(*key) }
+
+        with_redis do |redis|
+          # https://gitlab.com/gitlab-org/gitlab/-/issues/224171
+          Gitlab::Instrumentation::RedisClusterValidator.allow_cross_slot_commands do
+            redis.del(keys)
+          end
+        end
+      end
+
+      private
+
+      def key(model)
+        key_raw(model.build_id, model.chunk_index)
+      end
+
+      def key_raw(build_id, chunk_index)
+        "gitlab:ci:trace:#{build_id.to_i}:chunks:#{chunk_index.to_i}"
+      end
+    end
+  end
+end