ont-app.graph-log.archiving — ont-app/graph-log 0.2.0

Adds logic to archive the contents of log graphs on reset.

>>log-is-archived>> clj

A channel containing a series of archive-states reflecting the fact that the old log has been archived and a new one has been declared. Typically handlers of this channel will call set-continuing-from! on each archive-state to link the new log-graph back to the archive of the previous graph. Where

• set-continuing-from! := fn [archive-state] -> ? with side-effect of setting (@glog/log-graph :glog/LogGraph :glog/continuingFrom) to volume
• archive-state := {::volume ..., ...}
• volume is the file holding an edn representation of the previous incarnation of @glog/log-graph.

>>log-is-resetting>> clj

A channel which will call its handler (set in def-listener) on each reset-state Where handler := fn [reset-state] -> ? with side-effect of archving old-graph reset-state := {:old-graph ..., :new-graph ..., ...} old-graph is the old log-graph being reset to new-graph

archive-path clj

(archive-path g)

Returns a canonical name for an archive file for a log, caluclated per archive-path-fn derived from g Where

• g is a log-graph, Typically glog:LogGraph
• archive-path-fn := [g] -> archive-path. Or default-archive-path

VOCABULARY:

• <log-graph> :glog/archivePathFn <fn kw>
• <log-graph> :glog/timestamp <timestamp>
• <log-graph> :glog/archiveDirectory <directory URL>
• <fn kw> :igraph/compiledAs <fn [g] -> archive-path>

archive-to-file clj

(archive-to-file reset-state)

Side-effects: writes contents inferred from reset-state to archive-file and posts archive-state to >>log-is-archived>>. Where

• contents is old-graph minus new-graph, and anything that would choke a reader, rendered in EDN.
• reset-state := {::topic ::log-reset ::old-graph ... ::new-graph ... }
• archive-state := {::topic ::archive-state ::volume archive-file, ...}, merged with reset-state.
• old-graph is the previous contents of a log-graph
• new-graph is the newly reset log-graph
• archive-file is the path to a the contents written to disk.

check-archiving! clj

(check-archiving!)

(check-archiving! ms)

(check-archiving! gatom ms)

Side-effect: sets the :glog/continuingFrom relation in gatom Where

• gatom is an atom containing an IGraph, (default log-graph), it must be configured so as to enable archiving.
• ms is a timeout in milliseconds
• archive-state := {:glog/continuingFrom url, ...}
• url is typically the URL of the contents of the previous gatom, before the most recent call to log-reset!.

VOCABULARY:

• :glog/LogGraph - identifies the log graph itself in @log-graph
• :glog/FreshArchive - names type for LogGraph with 0 iterations
• <log-graph>:glog/iteration` <# of times graph has been reset>
• <log-graph>:glog/continuingFrom` <url of previous archived log iteration>

check-archiving-timeout clj

The timeout in ms for the check-archiving! function. Default is 1000

def-listener clj macro

(def-listener channel handler)

Expands to a go-loop which Binds to a channel a handler Where

• channel is an async port
• handler := [article] -> ?, typically with the side-effect of archiving article
• article is an item read from channel asynchronously. Typically in a format specific to channel.

default-archive-path clj

(default-archive-path g)

Returns rendering of {{directory}}/{{start}}-{{stop}}.edn Where

• directory is (g :glog/LogGraph :glog/archiveDirectory) or /tmp
• start is the timestamp of the 0th entry
• stop is the timestamp of the nth entry

VOCABULARY

• <graph-log> :glog/archiveDirectory directory (optional; default /tmp)
• <log entry> :glog/timestamp <epoch ms>

log-reset! clj

(log-reset!)

(log-reset! new-graph)

Side-effect: resets @log-graph to new-graph Side-effect: if (initial-graph:glog/ArchivePathFn igraph/compiledAs <path-fn>), the previous contents of the graph will be spit'd to <output-path> Where

• <initial-graph> is an IGraph, informed by ont-app.graph-log.core/ontology
• <path-fn> := fn [g] -> <output-path>
• <output-path> is a valid path specification , possibly starting with file://

VOCABULARY

• :glog/LogGraph - identifies the log graph itself in @log-graph
• <log-graph> :glog/iteration <# of times graph has been reset>
• <log-graph> :glog/archivePathFn <fn kw>
• <fn kw> :igraph/compiledAs <fn [g] -> archive path>

save-to-archive! clj

(save-to-archive! archive-path g)

Side-effect: Writes contents of g to archive-path, after removing stuff that would choke a reader. Returns archive-path for g Where:

• g is a graph derived from a log-graph

• archive-path is a path to which the contents of g are written, generated by (archive-path-fn g)

• archive-path-fn is a compiled function asserted with :glog/archivePathFn, or the default function archive-path.

  VOCABULARY

  • <log-graph> :glog/archivePathFn <fn kw>
  • <fn kw> :igraph/compiledAs <fn>

set-continuing-from! clj

(set-continuing-from! archive-state)

Side-effect: establishes :glog/coninuingFrom in value per archive-state in gatom Where

• archive-state := {::volume url, ...}
• gatom (optional) an atom containing an IGraph. Default is log-graph
• url is the URL of a location where the previous contents of @log-graph have been archived.
• Note: may throw error of type ::UnexpectedArchivingResult.

VOCABULARY:

• :glog/LogGraph
• <log-graph> :glog/continuingFrom url

tap-listeners? clj

Set to true when you want to tap> each article when it comes off a listener channel.

the clj

alias for igraph/unique

wait-for clj

(wait-for the-test ms)

Returns: non-falsey result of test, or ::timeout after ms milliseconds. Where

• result is a truthy response from test
• the-test := fn [] -> truthy value
• ms is max time to wait for test to be truthy