Support publishing build events

Add a table to store events, which have a type and a JSON blob. These can be
used to record changes, this commit inserts events when new builds are
created, and when the status of builds change.

The EventsOutbox table is then used to track when events have been sent
out. This is done through the new cuirass-send-events script.

* Makefile.am (bin_SCRIPTS): Add bin/cuirass-send-events.
.gitignore: Add bin/cuirass-send-events.
(dist_pkgmodule_DATA): Add src/cuirass/send-events.scm.
(dist_sql_DATA): Add src/sql/upgrade-5.sql.
(EXTRA_DIST): bin/cuirass-send-events.in.
(bin/cuirass-send-events): New rule.
* bin/cuirass-send-events.in: New file.
* src/cuirass/send-events.scm: New file.
* src/sql/upgrade-5.sql: New file.
* src/cuirass/database.scm (changes-count): New procedure.
(db-update-build-status!): Call db-add-event after updating the build status.
(db-add-event): New procedure.
(db-add-build): Insert an event when a new build is inserted.
(db-delete-events-with-ids-<=-to): New procedure.
* src/schema.sql (Events): New table.

8 files changed, 311 insertions, 13 deletions

diff --git a/.gitignore b/.gitignore
index 3bc363b..beabf29 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,6 +10,7 @@
 /aclocal.m4
 /autom4te.cache/
 /bin/cuirass
+/bin/cuirass-send-events
 /bin/evaluate
 /build-aux/config.guess
 /build-aux/config.sub
diff --git a/Makefile.am b/Makefile.am
index 7cea2ff..5448420 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,7 +21,7 @@
 # You should have received a copy of the GNU General Public License
 # along with Cuirass.  If not, see <http://www.gnu.org/licenses/>.
 
-bin_SCRIPTS = bin/cuirass bin/evaluate
+bin_SCRIPTS = bin/cuirass bin/cuirass-send-events bin/evaluate
 noinst_SCRIPTS = pre-inst-env
 
 guilesitedir = $(datarootdir)/guile/site/@GUILE_EFFECTIVE_VERSION@
@@ -45,6 +45,7 @@ dist_pkgmodule_DATA =				\
   src/cuirass/database.scm			\
   src/cuirass/http.scm				\
   src/cuirass/logging.scm			\
+  src/cuirass/send-events.scm			\
   src/cuirass/ui.scm				\
   src/cuirass/utils.scm             \
   src/cuirass/templates.scm
@@ -68,7 +69,8 @@ dist_sql_DATA = 				\
   src/sql/upgrade-1.sql				\
   src/sql/upgrade-2.sql				\
   src/sql/upgrade-3.sql				\
-  src/sql/upgrade-4.sql
+  src/sql/upgrade-4.sql				\
+  src/sql/upgrade-5.sql
 
 dist_css_DATA =					\
   src/static/css/bootstrap.css			\
@@ -143,6 +145,7 @@ sql-check: src/schema.sql
 EXTRA_DIST = \
   .dir-locals.el \
   bin/cuirass.in \
+  bin/cuirass-send-events.in \
   bin/evaluate.in \
   bootstrap \
   build-aux/guix.scm \
@@ -202,6 +205,7 @@ generate_file = \
 # These files depend on Makefile so they are rebuilt if $(VERSION),
 # $(datadir) or other do_subst'ituted variables change.
 bin/cuirass: $(srcdir)/bin/cuirass.in
+bin/cuirass-send-events: $(srcdir)/bin/cuirass-send-events.in
 bin/evaluate: $(srcdir)/bin/evaluate.in
 $(bin_SCRIPTS): Makefile
 	$(generate_file); chmod +x $@
diff --git a/bin/cuirass-send-events.in b/bin/cuirass-send-events.in
new file mode 100644
index 0000000..2373e46
--- /dev/null
+++ b/bin/cuirass-send-events.in
@@ -0,0 +1,80 @@
+#!/bin/sh
+# -*- scheme -*-
+# @configure_input@
+#GUILE_LOAD_PATH="@PACKAGE_LOAD_PATH@${GUILE_LOAD_PATH:+:}$GUILE_LOAD_PATH"
+#GUILE_LOAD_COMPILED_PATH="@PACKAGE_LOAD_COMPILED_PATH@${GUILE_LOAD_COMPILED_PATH:+:}$GUILE_LOAD_COMPILED_PATH"
+exec ${GUILE:-@GUILE@} --no-auto-compile -e main -s "$0" "$@"
+!#
+;;;; cuirass -- continuous integration tool
+;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
+;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
+;;; Copyright © 2018 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2018 Clément Lassieur <clement@lassieur.org>
+;;; Copyright © 2019 Christopher Baines <mail@cbaines.net>
+;;;
+;;; This file is part of Cuirass.
+;;;
+;;; Cuirass is free software: you can redistribute it and/or modify
+;;; it under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation, either version 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; Cuirass is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Cuirass.  If not, see <http://www.gnu.org/licenses/>.
+
+(use-modules (cuirass)
+             (cuirass ui)
+             (cuirass logging)
+             (cuirass utils)
+             (cuirass send-events)
+             (guix ui)
+             (fibers)
+             (fibers channels)
+             (srfi srfi-19)
+             (ice-9 getopt-long))
+
+(define (show-help)
+  (format #t "Usage: ~a [OPTIONS]~%" (%program-name))
+  (display "Send events to the target URL.
+
+  -T  --target-url=URL      Send events to URL.
+  -D  --database=DB         Use DB to store build results.
+  -h, --help                Display this help message")
+  (newline)
+  (show-package-information))
+
+(define %options
+  '((target-url     (single-char #\T) (value #t))
+    (database       (single-char #\D) (value #t))
+    (help           (single-char #\h) (value #f))))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define* (main #:optional (args (command-line)))
+
+  ;; Always have stdout/stderr line-buffered.
+  (setvbuf (current-output-port) 'line)
+  (setvbuf (current-error-port) 'line)
+
+  (let ((opts (getopt-long args %options)))
+    (parameterize
+        ((%program-name     (car args))
+         (%package-database (option-ref opts 'database (%package-database)))
+         (%package-cachedir
+          (option-ref opts 'cache-directory (%package-cachedir))))
+      (cond
+       ((option-ref opts 'help #f)
+        (show-help)
+        (exit 0))
+       (else
+        (while #t
+          (send-events (option-ref opts 'target-url #f))
+          (sleep 5)))))))
diff --git a/bin/cuirass.in b/bin/cuirass.in
index 81ce9fe..fbc7c3c 100644
--- a/bin/cuirass.in
+++ b/bin/cuirass.in
@@ -54,6 +54,7 @@ exec ${GUILE:-@GUILE@} --no-auto-compile -e main -s "$0" "$@"
       --listen=HOST         Listen on the network interface for HOST
   -I, --interval=N          Wait N seconds between each poll
       --use-substitutes     Allow usage of pre-built substitutes
+      --record-events       Record events for distribution
       --threads=N           Use up to N kernel threads
   -V, --version             Display version
   -h, --help                Display this help message")
@@ -72,6 +73,7 @@ exec ${GUILE:-@GUILE@} --no-auto-compile -e main -s "$0" "$@"
     (use-substitutes                  (value #f))
     (threads                          (value #t))
     (fallback                         (value #f))
+    (record-events                    (value #f))
     (ttl                              (value #t))
     (version        (single-char #\V) (value #f))
     (help           (single-char #\h) (value #f))))
@@ -95,6 +97,7 @@ exec ${GUILE:-@GUILE@} --no-auto-compile -e main -s "$0" "$@"
           (option-ref opts 'cache-directory (%package-cachedir)))
          (%use-substitutes? (option-ref opts 'use-substitutes #f))
          (%fallback? (option-ref opts 'fallback #f))
+         (%record-events? (option-ref opts 'record-events #f))
          (%gc-root-ttl
           (time-second (string->duration (option-ref opts 'ttl "30d")))))
       (cond
diff --git a/src/cuirass/database.scm b/src/cuirass/database.scm
index 523165d..9cd2e8f 100644
--- a/src/cuirass/database.scm
+++ b/src/cuirass/database.scm
@@ -54,6 +54,9 @@
             db-get-builds-max
             db-get-builds-query-min
             db-get-builds-query-max
+            db-add-event
+            db-get-events
+            db-delete-events-with-ids-<=-to
             db-get-evaluations
             db-get-evaluations-build-summary
             db-get-evaluations-id-min
@@ -67,6 +70,7 @@
             %package-database
             %package-schema-file
             %db-channel
+            %record-events?
             ;; Macros.
             with-db-critical-section
             with-database))
@@ -164,6 +168,9 @@ specified."
 (define %db-channel
   (make-parameter #f))
 
+(define %record-events?
+  (make-parameter #f))
+
 (define-syntax-rule (with-db-critical-section db exp ...)
   "Evaluate EXP... in the critical section corresponding to %DB-CHANNEL.
 DB is bound to the argument of that critical section: the database
@@ -270,6 +277,12 @@ database object."
   (vector-ref (car (sqlite-exec db "SELECT last_insert_rowid();"))
               0))
 
+(define (changes-count db)
+  "The number of database rows that were changed or inserted or deleted by the
+most recently completed INSERT, DELETE, or UPDATE statement."
+  (vector-ref (car (sqlite-exec db "SELECT changes();"))
+              0))
+
 (define (expect-one-row rows)
   "Several SQL queries expect one result, or zero if not found.  This gets rid
 of the list, and returns #f when there is no result."
@@ -504,7 +517,15 @@ VALUES ("
        (if (null? new-outputs)
            (begin (sqlite-exec db "ROLLBACK;")
                   #f)
-           (begin (sqlite-exec db "COMMIT;")
+           (begin (db-add-event 'build
+                                (assq-ref build #:timestamp)
+                                `((#:derivation . ,(assq-ref build #:derivation))
+                                  ;; TODO Ideally this would use the value
+                                  ;; from build, with a default of scheduled,
+                                  ;; but it's hard to convert to the symbol,
+                                  ;; so just hard code scheduled for now.
+                                  (#:event       . scheduled)))
+                  (sqlite-exec db "COMMIT;")
                   derivation)))
 
      ;; If we get a unique-constraint-failed error, that means we have
@@ -521,23 +542,42 @@ log file for DRV."
   (define now
     (time-second (current-time time-utc)))
 
+  (define status-names
+    `((,(build-status succeeded)         . "succeeded")
+      (,(build-status failed)            . "failed")
+      (,(build-status failed-dependency) . "failed (dependency)")
+      (,(build-status failed-other)      . "failed (other)")
+      (,(build-status canceled)          . "canceled")))
+
   (with-db-critical-section db
     (if (= status (build-status started))
-        (sqlite-exec db "UPDATE Builds SET starttime=" now ", status="
-                     status "WHERE derivation=" drv ";")
+        (begin
+          (sqlite-exec db "UPDATE Builds SET starttime=" now ", status="
+                       status "WHERE derivation=" drv ";")
+          (db-add-event 'build
+                        now
+                        `((#:derivation . ,drv)
+                          (#:event      . started))))
 
         ;; Update only if we're switching to a different status; otherwise
         ;; leave things unchanged.  This ensures that 'stoptime' remains valid
         ;; and doesn't change every time we mark DRV as 'succeeded' several
         ;; times in a row, for instance.
-        (if log-file
-            (sqlite-exec db "UPDATE Builds SET stoptime=" now
-                         ", status=" status ", log=" log-file
-                         "WHERE derivation=" drv "AND status != " status ";")
-            (sqlite-exec db "UPDATE Builds SET stoptime=" now
-                         ", status=" status
-                         "WHERE derivation=" drv " AND status != " status
-                         ";")))))
+        (begin
+          (if log-file
+              (sqlite-exec db "UPDATE Builds SET stoptime=" now
+                           ", status=" status ", log=" log-file
+                           "WHERE derivation=" drv "AND status != " status ";")
+              (sqlite-exec db "UPDATE Builds SET stoptime=" now
+                           ", status=" status
+                           "WHERE derivation=" drv " AND status != " status
+                           ";"))
+          (when (positive? (changes-count db))
+            (db-add-event 'build
+                          now
+                          `((#:derivation . ,drv)
+                            (#:event      . ,(assq-ref status-names
+                                                       status)))))))))
 
 (define (db-get-outputs derivation)
   "Retrieve the OUTPUTS of the build identified by DERIVATION in the
@@ -741,6 +781,63 @@ ORDER BY ~a, rowid ASC;" order))
     (let ((key (if (number? derivation-or-id) 'id 'derivation)))
       (expect-one-row (db-get-builds `((,key . ,derivation-or-id)))))))
 
+(define (db-add-event type timestamp details)
+  (when (%record-events?)
+    (with-db-critical-section db
+      (sqlite-exec db "\
+INSERT INTO Events (type, timestamp, event_json) VALUES ("
+                   (symbol->string type) ", "
+                   timestamp ", "
+                   (object->json-string details)
+                   ");")
+      #t)))
+
+(define (db-get-events filters)
+  (with-db-critical-section db
+    (let* ((stmt-text "\
+SELECT Events.id,
+       Events.type,
+       Events.timestamp,
+       Events.event_json
+FROM Events
+WHERE (:type IS NULL OR (:type = Events.type))
+  AND (:borderlowtime IS NULL OR
+       :borderlowid IS NULL OR
+       ((:borderlowtime, :borderlowid) <
+        (Events.timestamp, Events.id)))
+  AND (:borderhightime IS NULL OR
+       :borderhighid IS NULL OR
+       ((:borderhightime, :borderhighid) >
+        (Events.timestamp, Events.id)))
+ORDER BY Events.id ASC
+LIMIT :nr;")
+           (stmt (sqlite-prepare db stmt-text #:cache? #t)))
+      (sqlite-bind-arguments
+       stmt
+       #:type (and=> (assq-ref filters 'type)
+                     symbol->string)
+       #:nr (match (assq-ref filters 'nr)
+              (#f -1)
+              (x x)))
+      (sqlite-reset stmt)
+      (let loop ((rows (sqlite-fold-right cons '() stmt))
+                 (events '()))
+        (match rows
+          (() (reverse events))
+          ((#(id type timestamp event_json) . rest)
+           (loop rest
+                 (cons `((#:id . ,id)
+                         (#:type . ,type)
+                         (#:timestamp . ,timestamp)
+                         (#:event_json . ,event_json))
+                       events))))))))
+
+(define (db-delete-events-with-ids-<=-to id)
+  (with-db-critical-section db
+    (sqlite-exec
+     db
+     "DELETE FROM Events WHERE id <= " id ";")))
+
 (define (db-get-pending-derivations)
   "Return the list of derivation file names corresponding to pending builds in
 the database.  The returned list is guaranteed to not have any duplicates."
diff --git a/src/cuirass/send-events.scm b/src/cuirass/send-events.scm
new file mode 100644
index 0000000..3ff5295
--- /dev/null
+++ b/src/cuirass/send-events.scm
@@ -0,0 +1,91 @@
+;;;; http.scm -- HTTP API
+;;; Copyright © 2019 Christopher Baines <mail@cbaines.net>
+;;;
+;;; This file is part of Cuirass.
+;;;
+;;; Cuirass is free software: you can redistribute it and/or modify
+;;; it under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation, either version 3 of the License, or
+;;; (at your option) any later version.
+;;;
+;;; Cuirass is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Cuirass.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (cuirass send-events)
+  #:use-module (cuirass config)
+  #:use-module (cuirass database)
+  #:use-module (cuirass utils)
+  #:use-module (cuirass logging)
+  #:use-module (web client)
+  #:use-module (web response)
+  #:use-module (json)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
+  #:use-module (rnrs bytevectors)
+  #:use-module (ice-9 textual-ports)
+  #:export (send-events))
+
+(define* (send-events target-url
+                      #:key (batch-limit 100))
+  "Send up to BATCH-LIMIT events to TARGET-URL"
+  (with-exponential-backoff-upon-error
+   (lambda ()
+     (let ((events-to-send
+            (db-get-events `((nr . ,batch-limit)))))
+       (unless (null? events-to-send)
+         (let ((body
+                (object->json-string
+                 `((items
+                    . ,(list->vector
+                        (map (lambda (event)
+                               (let ((event-json
+                                      (json-string->scm
+                                       (assq-ref event #:event_json))))
+                                 `((id        . ,(assq-ref event #:id))
+                                   (type      . ,(assq-ref event #:type))
+                                   (timestamp . ,(assq-ref event #:timestamp))
+                                   ,@event-json)))
+                             events-to-send)))))))
+           (let*-values
+               (((response body)
+                 (http-post target-url
+                            #:body body
+                            ;; Guile doesn't treat JSON as text, so decode the
+                            ;; body manually
+                            #:decode-body? #f))
+                ((code)
+                 (response-code response)))
+             (unless (and (>= code 200)
+                          (< code 300))
+               (throw
+                'request-failure
+                (simple-format #f "code: ~A response: ~A"
+                               code
+                               (utf8->string body))))))
+         (db-delete-events-with-ids-<=-to
+          (assq-ref (last events-to-send) #:id))
+         (simple-format #t "Sent ~A events\n" (length events-to-send)))))))
+
+(define* (with-exponential-backoff-upon-error thunk #:key (retry-number 1))
+  "Call THUNK and catch exceptions, retrying after a number of seconds that
+increases exponentially."
+  (catch
+    #t
+    thunk
+    (lambda (key . args)
+      (simple-format (current-error-port)
+                     "Failure sending events (try ~A)\n"
+                     retry-number)
+      (print-exception (current-error-port) #f key args)
+      (let ((sleep-length (integer-expt 2 retry-number)))
+        (simple-format (current-error-port)
+                       "\nWaiting for ~A seconds\n"
+                       sleep-length)
+        (sleep sleep-length)
+        (with-exponential-backoff-upon-error thunk #:retry-number
+                                             (+ retry-number 1))))))
diff --git a/src/schema.sql b/src/schema.sql
index a9e4a6a..cd67530 100644
--- a/src/schema.sql
+++ b/src/schema.sql
@@ -64,6 +64,13 @@ CREATE TABLE Builds (
   FOREIGN KEY (evaluation) REFERENCES Evaluations (id)
 );
 
+CREATE TABLE Events (
+  id            INTEGER PRIMARY KEY,
+  type          TEXT NOT NULL,
+  timestamp     INTEGER NOT NULL,
+  event_json    TEXT NOT NULL
+);
+
 -- Create indexes to speed up common queries, in particular those
 -- corresponding to /api/latestbuilds and /api/queue HTTP requests.
 CREATE INDEX Builds_index ON Builds(job_name, system, status ASC, timestamp ASC, derivation, evaluation, stoptime DESC);
diff --git a/src/sql/upgrade-5.sql b/src/sql/upgrade-5.sql
new file mode 100644
index 0000000..8f30bde
--- /dev/null
+++ b/src/sql/upgrade-5.sql
@@ -0,0 +1,15 @@
+BEGIN TRANSACTION;
+
+CREATE TABLE Events (
+  id            INTEGER PRIMARY KEY,
+  type          TEXT NOT NULL,
+  timestamp     INTEGER NOT NULL,
+  event_json    TEXT NOT NULL
+);
+
+CREATE TABLE EventsOutbox (
+  event_id INTEGER NOT NULL,
+  FOREIGN KEY (event_id) REFERENCES Events (id)
+);
+
+COMMIT;