3b02d77ceb
This changes everything with external visibility beyond the codebase (i.e. the name of the compiled binary and the documentation that refers to it). It does not change a lot of things internal to the codebase, i.e. the "RegistryTool" class didn't change its name. We can rename that in a subsequent CL if we want to. ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=135022087
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Code structure
This document contains information on the overall structure of the code, and how particularly important pieces of the system are implemented.
Dagger dependency injection
Bazel build system
Flows
Commit logs and backups
Cursors
Cursors are DateTime pointers used to ensure rolling transactional isolation
of various reporting and other maintenance operations. Utilizing a Cursor
within an operation ensures that instances in time are processed exactly once
for a given task, and that tasks can catch up from any failure states at any
time.
Cursors are rolled forward at the end of successful tasks, are not rolled
forward in the case of failure, and can be manually set backwards using the
nomulus update_cursors command to reprocess a past action.
The following cursor types are defined:
BRDA- BRDA (thin) escrow depositsRDE_REPORT- XML RDE report uploadsRDE_STAGING- RDE (thick) escrow deposit stagingRDE_UPLOAD- RDE (thick) escrow deposit uploadRDE_UPLOAD_SFTP- Cursor that tracks the last time we talked to the escrow provider's SFTP server for a given TLD.RECURRING_BILLING- Expansion ofRecurring(renew) billing events intoOneTimeevents.
All Cursor entities in Datastore contain a DateTime that represents the next
timestamp at which an operation should resume processing and a CursorType that
identifies which operation the cursor is associated with. In many cases, there
are multiple cursors per operation; for instance, the cursors related to RDE
reporting, staging, and upload are per-TLD cursors. To accomplish this, each
Cursor also has a scope, a Key<ImmutableObject> to which the particular
cursor applies (this can be e.g. a Registry or any other ImmutableObject in
datastore, depending on the operation). If the Cursor applies to the entire
registry environment, it is considered a global cursor and has a scope of
EntityGroupRoot.getCrossTldKey().
Cursors are singleton entities by type and scope. The id for a Cursor is a
deterministic string that consists of the websafe string of the Key of the scope
object concatenated with the name of the name of the cursor type, separated by
an underscore.
Mapreduces
Actions and servlets
Foreign key indexes
Point-in-time accuracy
Guava
EPP resource hierarchy
Poll messages
Poll messages are the mechanism by which EPP handles asynchronous communication between the registry and registrars. Refer to RFC 5730 Section 2.9.2.3 for their protocol specification.
Poll messages are stored by the system as entities in Datastore. All poll messages have an event time at which they become active; any poll request before that time will not return the poll message. For example, every domain when created speculatively enqueues a poll message for the automatic renewal of the domain a year later. This poll message won't be delivered until that year elapses, and if some change to the domain occurs prior to that point, such as it being deleted, then the speculative poll message will be deleted and thus never delivered. Other poll messages are effective immediately, e.g. the poll message generated for the owning registrar when another registrar requests the transfer of a domain. These messages are written out with an event time of when they were created, and will thus be delivered whenever the registrar next polls for messages.
PollMessage is the abstract base class for the two different types of poll
messages that extend it:
Autorenew- A poll message corresponding to an automatic renewal of a domain. It recurs annually.OneTime- A one-time poll message used for everything else.
Queries for poll messages by the registrar are handled in PollRequestFlow, and
poll messages are ACKed (and thus deleted) in PollAckFlow.