Add new "lock" command #619
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| @@ -24,6 +24,11 @@ const ( | |||
| // before attempting to do the lock again. This is so that once a lock-delay | |||
| // is in affect, we do not hot loop retrying the acquisition. | |||
| DefaultLockRetryTime = 5 * time.Second | |||
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| // LockFlagValue is a magic flag we set to indicate a key | |||
| // is being used for a semaphore. It is used to detect a potential | |||
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Wording just seems reversed here. NBD but confused me.
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@armon This looks great! Only minor nit-picks added. Otherwise this LGTM. Glad to see a SIGTERM attempt before SIGKILL in here, too! |
| case <-time.After(ttl / 2): | ||
| entry, _, err := s.Renew(id, q) | ||
| if err != nil { | ||
| return err |
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Is it possible for a client to believe it holds the lock when it doesn't if this returns with an error? (since we're in a goroutine and not funneling errors down a channel)
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Both the Lock and Semaphore implementations will catch this and release the lock. e.g. eventually the session gets invalidated, and then they release the lock.
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@armon added one more question about |
| uses the [leader election algorithm](/docs/guides/leader-election.html). | ||
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| If the lock holder count is more than one, then a semaphore is used instead. | ||
| A semaphore allows more than a single holder, but the is less efficient than |
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It would be good to clarify the -n option: if a client A says -n1, client B says -n2, does that mean client B gets in? It'd be good if the number of lock holders is encoded in the lock such that -n2 will block until it wins the lock from an -n1. If that's not possible, then a note in the docs should exist to say that |
| layout: "docs" | ||
| page_title: "Commands: Lock" | ||
| sidebar_current: "docs-commands-lock" | ||
| description: |- |
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I think @sethvargo mentioned that the description needs to be a single line of text for SEO reasons. You can use > in place of |- to do this in YAML.
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Thanks! I've fixed this in d478f78
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@sean- the |
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Thank you!, that looks great. I'm pleasantly impressed and surprised by the fact that this was coded (correctly) in advance. Good forethought and design by whomever. Consul++. |
[sync-catalog] Fix NodePort register service with wrong internal IP when multiple internal IPs are reported on the node
This PR adds a new "consul lock" command. This command can be used to easy do distributed locking for N+1 deploys of highly available services.