3900683413
Previously: the service wrote a timestamp and the receiver read and parsed it to see if there was new data Now: the service writes and removes a .lock file to prevent the receiver reading partial data. The receiver is responsible for remembering the *previous* state and only updating if it's changed
64 lines
1.4 KiB
Fennel
64 lines
1.4 KiB
Fennel
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(local state-directory (assert (os.getenv "SERVICE_STATE")))
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(os.execute (.. "mkdir -p " state-directory))
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(fn write-value [name value]
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(let [path (.. state-directory "/" name)]
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(with-open [fout (io.open path :w)]
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(when value (fout:write value)))))
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(fn write-value-from-env [name]
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(write-value name (os.getenv (string.upper name))))
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;; we remove state before updating to ensure that consumers don't get
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;; a half-updated snapshot
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(os.remove (.. state-directory "/state"))
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(let [wanted
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[
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:addresses
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:aftr
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:cer
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:domains
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:lw406
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:mape
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:mapt
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:ntp_fqdn
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:ntp_ip
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:option_1
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:option_2
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:option_3
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:option_4
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:option_5
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:passthru
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:prefixes
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:ra_addresses
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:ra_dns
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:ra_domains
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:ra_hoplimit
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:ra_mtu
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:ra_reachable
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:ra_retransmit
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:ra_routes
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:rdnss
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:server
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:sip_domain
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:sip_ip
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:sntp_ip
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:sntp_fqdn
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]]
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(each [_ n (ipairs wanted)]
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(write-value-from-env n)))
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(let [[ifname state] arg
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ready (match state
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"started" false
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"unbound" false
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"stopped" false
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_ true)]
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(write-value ".lock" (tostring (os.time)))
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(write-value "ifname" ifname)
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(write-value "state" state)
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(os.remove (.. state-directory "/.lock"))
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(when ready
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(with-open [fd (io.open "/proc/self/fd/10" :w)] (fd:write "\n"))))
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