tools/hydra-to-docker-repo: fetch latest finished build for job

Digging deeper into the Hydra API, a way to fetch the latest succeeding job
already exists, which provides all the information we need.

tools/hydra-to-docker-repo/hydra/query.go

@@ -24,6 +24,7 @@ type Hydra struct {
 	client  *http.Client
 }
 
+// New initializes a Hydra connection.
 func New(baseUrl url.URL) *Hydra {
 	return &Hydra{
 		baseUrl: baseUrl,
@@ -31,6 +32,18 @@ func New(baseUrl url.URL) *Hydra {
 	}
 }
 
+// JobsetRef references a hydra Jobset.
+type JobsetRef struct {
+	Project string
+	Name    string
+}
+
+// JobRef references a hydra Job.
+type JobRef struct {
+	Jobset JobsetRef
+	Name   string
+}
+
 // Endpoint of hydra that can be queried.
 type Endpoint string
 
@@ -45,6 +58,7 @@ type EvalResponse struct {
 	}
 }
 
+// Eval the result of a Hydra evaluation.
 type Eval struct {
 	HasNewBuilds bool
 	Builds       []int
@@ -78,11 +92,14 @@ func responseToEvals(resp *EvalResponse) (*Evals, error) {
 	return &evals, nil
 }
 
+// BuildOutput is a nix derivation output, like "doc".
 type BuildOutput struct {
 	// nix storepath of output
 	Path string
 }
 
+// BuildProduct is a Hydra build product
+// (in the magic `nix-support/hydra-build-products` file of an output).
 type BuildProduct struct {
 	// name of build output
 	Name string
@@ -108,6 +125,7 @@ type BuildResponse struct {
 	Job string
 }
 
+// Build is a Hydra Build.
 type Build struct {
 	Id              int
 	BuildSuccessful bool
@@ -186,8 +204,7 @@ func (h *Hydra) fetchJson(e Endpoint) (io.ReadCloser, error) {
 
 }
 
-func (h *Hydra) FetchBuild(buildId int) (*Build, error) {
-	endp, _ := MkEndpoint("build/" + strconv.Itoa(buildId))
+func (h *Hydra) FetchBuildFromEndpoint(endp Endpoint) (*Build, error) {
 	response, err := h.fetchJson(endp)
 	if err != nil {
 		return nil, err
@@ -203,8 +220,23 @@ func (h *Hydra) FetchBuild(buildId int) (*Build, error) {
 	return responseToBuild(&result)
 }
 
-func (h *Hydra) FetchEval(project string, jobset string) (*Evals, error) {
-	endp, _ := MkEndpoint(fmt.Sprintf("jobset/%s/%s/evals", project, jobset))
+// FetchBuild by Hydra build id.
+func (h *Hydra) FetchBuild(buildId int) (*Build, error) {
+	endp, _ := MkEndpoint("build/" + strconv.Itoa(buildId))
+	return h.FetchBuildFromEndpoint(endp)
+}
+
+// FetchLatestFinishedBuild for a Hydra job.
+func (h *Hydra) FetchLatestFinishedBuild(job JobRef) (*Build, error) {
+	endp, _ := MkEndpoint(fmt.Sprintf("job/%s/%s/%s/latest-finished",
+		job.Jobset.Project, job.Jobset.Name, job.Name))
+	return h.FetchBuildFromEndpoint(endp)
+}
+
+// FetchEvals for a Hydra jobset.
+func (h *Hydra) FetchEvals(jobset JobsetRef) (*Evals, error) {
+	endp, _ := MkEndpoint(
+		fmt.Sprintf("jobset/%s/%s/evals", jobset.Project, jobset.Name))
 	response, err := h.fetchJson(endp)
 	if err != nil {
 		return nil, err

tools/hydra-to-docker-repo/main.go

@@ -17,9 +17,23 @@ func main() {
 	}
 	fmt.Printf("%+v\n", build)
 
-	eval, err := h.FetchEval("techcultivation", "sangha-deployment")
+	eval, err := h.FetchEvals(hydra.JobsetRef{
+		Project: "techcultivation",
+		Name:    "sangha-deployment"})
 	if err != nil {
 		fmt.Println(err)
 	}
 	fmt.Printf("%+v\n", eval)
+
+	build, err = h.FetchLatestFinishedBuild(hydra.JobRef{
+		Name: "downloads.dockerImages.sangha.postgres",
+		Jobset: hydra.JobsetRef{
+			Project: "techcultivation",
+			Name:    "sangha-deployment",
+		},
+	})
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Printf("%+v\n", build)
 }