Add support for "initial_version" to allow auto-populating the first version

README.md

@@ -62,8 +62,40 @@ level of precision is better left to other tools.
   days: [Monday, Wednesday]
   ```
 
-These can be combined to emit a new version on an interval during a particular
-time period.
+  These can be combined to emit a new version on an interval during a particular
+  time period.
+
+* `initial_version`: *Optional.* When using `start` and `stop` as a trigger for
+  a job, you will be unable to run the job manually until it goes into the
+  configured time range for the first time (manual runs will work once the `time`
+  resource has produced it's first version).
+
+  To get around this issue, there are two approaches:
+     * Use `initial_version: true`, which will produce a new version that is
+       set to the current time, if `check` runs and there isn't already a version
+       specified. **NOTE: This has a downside that if used with `trigger: true`, it will
+       kick off the correlating job when the pipeline is first created, even
+       outside of the specified window**.
+     * Alternatively, once you push a pipeline that utilizes `start` and `stop`, run the
+       following fly command to run the resource check from a previous point
+       in time (see [this issue](https://github.com/concourse/time-resource/issues/24#issuecomment-689422764)
+       for 6.x.x+ or [this issue](https://github.com/concourse/time-resource/issues/11#issuecomment-562385742)
+       for older Concourse versions).
+
+       ```
+       fly -t <your target> \
+         check-resource <your resource>
+         --from "time:2000-01-01T00:00:00Z" # the important part
+       ```
+
+       This has the benefit that it shouldn't trigger that initial job run, but
+       will still allow you to manually run the job if needed.
+
+  e.g.
+
+  ```
+  initial_version: true
+  ```
 
 ## Behavior
 

check_command.go

@@ -37,6 +37,9 @@ func (*CheckCommand) Run(request models.CheckRequest) ([]models.Version, error)
 
 	if !previousTime.IsZero() {
 		versions = append(versions, models.Version{Time: previousTime})
+	} else if request.Source.InitialVersion {
+		versions = append(versions, models.Version{Time: currentTime})
+		return versions, nil
 	}
 
 	if tl.Check(currentTime) {

dockerfiles/ubuntu/Dockerfile

@@ -1,4 +1,4 @@
-ARG base_image
+ARG base_image=ubuntu:latest
 ARG builder_image=concourse/golang-builder
 
 FROM ${builder_image} AS builder
@@ -12,19 +12,19 @@ RUN go build -o /assets/out github.com/concourse/time-resource/out
 RUN go build -o /assets/in github.com/concourse/time-resource/in
 RUN go build -o /assets/check github.com/concourse/time-resource/check
 RUN set -e; for pkg in $(go list ./...); do \
-		go test -o "/tests/$(basename $pkg).test" -c $pkg; \
+	go test -o "/tests/$(basename $pkg).test" -c $pkg; \
 	done
 
 FROM ${base_image} AS resource
 RUN apt update && apt upgrade -y -o Dpkg::Options::="--force-confdef"
 RUN apt update && apt install -y --no-install-recommends tzdata \
-    && rm -rf /var/lib/apt/lists/*
+	&& rm -rf /var/lib/apt/lists/*
 COPY --from=builder /assets /opt/resource
 
 FROM resource AS tests
 COPY --from=builder /tests /tests
 RUN set -e; for test in /tests/*.test; do \
-		$test; \
+	$test; \
 	done
 
 FROM resource

models/models.go

@@ -39,11 +39,12 @@ type CheckRequest struct {
 type CheckResponse []Version
 
 type Source struct {
-	Interval *Interval  `json:"interval"`
-	Start    *TimeOfDay `json:"start"`
-	Stop     *TimeOfDay `json:"stop"`
-	Days     []Weekday  `json:"days"`
-	Location *Location  `json:"location"`
+	InitialVersion bool       `json:"initial_version"`
+	Interval       *Interval  `json:"interval"`
+	Start          *TimeOfDay `json:"start"`
+	Stop           *TimeOfDay `json:"stop"`
+	Days           []Weekday  `json:"days"`
+	Location       *Location  `json:"location"`
 }
 
 func (source Source) Validate() error {