dmt: Implement API endpoint /api/status

This returns high-level information describing the current state of the
system.

The intent of the `version` field is primarily to act as a "page should
be reloaded" indicator to the front-end javascript code.  This would
inform the client to reload (possibly) new markup or script whenever the
version field changes.  This field could return an accurate version
spec of cychedelic or DMT, however just returns a random string at the
moment which is tied to the DMT docker image build.

Signed-off-by: Malfurious <m@lfurio.us>

2 files changed, 37 insertions, 0 deletions

diff --git a/dmt/Dockerfile b/dmt/Dockerfile
index 6d53838..f440d5e 100644
--- a/dmt/Dockerfile
+++ b/dmt/Dockerfile
@@ -14,6 +14,7 @@ ENV GOPATH="/usr/local"
 COPY . .
 
 RUN go install github.com/uriel/cgd@latest
+RUN tr -dc a-z </dev/urandom | head -c 12 >/version
 
 EXPOSE 80
 CMD ["cgd", "-a", ":80", "-c", "dmt"]
diff --git a/dmt/dmt b/dmt/dmt
new file mode 100755
index 0000000..9de6e37
--- /dev/null
+++ b/dmt/dmt
@@ -0,0 +1,36 @@
+#!/bin/bash -a
+
+# cychedelic DMT daemon
+# cychedelic is an automated Continuous Deployment solution.  See the README for
+# more information.
+
+CYCHE_LOG_DIR="/data/logs"
+CYCHE_STATUS_FILE="/data/status"
+CYCHE_VERSION_FILE="/version"
+
+integer() {
+    [ "$1" -eq "$1" ] >/dev/null 2>&1
+}
+
+newest_job() {
+    ls -A "$CYCHE_LOG_DIR" | sort -rn | head -n1
+}
+
+oldest_job() {
+    ls -A "$CYCHE_LOG_DIR" | sort -n | head -n1
+}
+
+api_status() {
+    status=$(cat "$CYCHE_STATUS_FILE")
+    [ "$status" == "" ] && active="false" || active="true"
+    integer "$status" && job="$status" || job="-1"
+
+    printf 'Content-type: text/json\n\n{'
+    printf '"version":"%s",' "$(cat "$CYCHE_VERSION_FILE")"
+    printf '"active":%s,' "$active"
+    printf '"job":%i,' "$job"
+    printf '"newest":%i,' "$(newest_job)"
+    printf '"oldest":%i}' "$(oldest_job)"
+}
+
+api_status