WIP Moving back towards using named runs.

* Rename artifactsRepo -> buildDataDir to be more explicit about the fact that
  it holds more than just the artifacts.
* Revert removal of run ids.
* Move Worker definition into core as part of making the core responsible for
  accepting run requests.
* Make the core module more responsible for internal details of data structure
  and storage. External callers should not need to construct paths to
  artifacts, versions, etc. but should be able to call method in the core
  module to do this work for them.
* The working directory no longer contains anything but the checked-out code.
  All StrawBoss-specific data is stored by StrawBoss elsewhere.
* Add a regular maintenance cycle to the server module.

src/main/nim/strawbosspkg/configuration.nim

@@ -1,4 +1,4 @@
-import cliutils, logging, json, os, nre, sequtils, strtabs, tables, times
+import cliutils, logging, json, os, nre, sequtils, strtabs, tables, times, uuids
 
 from langutils import sameContents
 from typeinfo import toAny
@@ -7,7 +7,7 @@ from typeinfo import toAny
 #
 type
   BuildStatus* = object
-    state*, details*: string
+    runId*, state*, details*: string
 
   Step* = object
     name*, stepCmd*, workingDir*: string
@@ -24,6 +24,7 @@ type
     envVars*: StringTableRef
 
   RunRequest* = object
+    id*: UUID
     projectName*, stepName*, buildRef*, workspaceDir*: string
     forceRebuild*: bool
 
@@ -34,7 +35,7 @@ type
   UserRef* = ref User
 
   StrawBossConfig* = object
-    artifactsRepo*: string
+    buildDataDir*: string
     authSecret*: string
     filePath*: string
     debug*: bool
@@ -60,7 +61,7 @@ proc `==`*(a, b: ProjectDef): bool =
 
 proc `==`*(a, b: StrawBossConfig): bool =
   result =
-    a.artifactsRepo == b.artifactsRepo and
+    a.buildDataDir == b.buildDataDir and
     a.authSecret == b.authSecret and
     a.pwdCost == b.pwdCost and
     sameContents(a.users, b.users) and
@@ -68,6 +69,7 @@ proc `==`*(a, b: StrawBossConfig): bool =
 
 proc `==`*(a, b: RunRequest): bool =
   result =
+    a.id == b.id and
     a.projectName == b.projectName and
     a.stepName == b.stepName and
     a.buildRef == b.buildRef and
@@ -130,7 +132,7 @@ proc parseStrawBossConfig*(jsonCfg: JsonNode): StrawBossConfig =
       hashedPwd: uJson.getOrFail("hashedPwd", "user record").getStr))
 
   result = StrawBossConfig(
-    artifactsRepo: jsonCfg.getIfExists("artifactsRepo").getStr("artifacts"),
+    buildDataDir: jsonCfg.getIfExists("buildDataDir").getStr("build-data"),
     authSecret: jsonCfg.getOrFail("authSecret", "strawboss config").getStr,
     debug: jsonCfg.getIfExists("debug").getBVal(false),
     pwdCost: int8(jsonCfg.getOrFail("pwdCost", "strawboss config").getNum),
@@ -189,11 +191,13 @@ proc loadBuildStatus*(statusFile: string): BuildStatus =
   let jsonObj = parseFile(statusFile)
 
   result = BuildStatus(
+    runId: jsonObj.getOrFail("runId", "run ID").getStr,
     state: jsonObj.getOrFail("state", "build status").getStr,
     details: jsonObj.getIfExists("details").getStr("") )
 
 proc parseRunRequest*(reqJson: JsonNode): RunRequest =
   result = RunRequest(
+    id: parseUUID(reqJson.getOrFail("id", "RunRequest").getStr),
     projectName: reqJson.getOrFail("projectName", "RunRequest").getStr,
     stepName: reqJson.getOrFail("stepName", "RunRequest").getStr,
     buildRef: reqJson.getOrFail("buildRef", "RunRequest").getStr,
@@ -203,6 +207,7 @@ proc parseRunRequest*(reqJson: JsonNode): RunRequest =
 # TODO: can we use the marshal module for this?
 proc `%`*(s: BuildStatus): JsonNode =
   result = %* {
+    "runId": s.runId,
     "state": s.state,
     "details": s.details }
 
@@ -238,6 +243,7 @@ proc `%`*(p: ProjectConfig): JsonNode =
 
 proc `%`*(req: RunRequest): JsonNode =
   result = %* {
+    "id": $(req.id),
     "projectName": req.projectName,
     "stepName": req.stepName,
     "buildRef": req.buildRef,
@@ -251,7 +257,7 @@ proc `%`*(user: User): JsonNode =
 
 proc `%`*(cfg: StrawBossConfig): JsonNode =
   result = %* {
-    "artifactsRepo": cfg.artifactsRepo,
+    "buildDataDir": cfg.buildDataDir,
     "authSecret": cfg.authSecret,
     "debug": cfg.debug,
     "projects": %cfg.projects,