Build Result

1. Property Successful Build Result
2. Property Failed Build Result
3. The following properties are required
4. Property timesBuilt
5. Property startTime
6. Property stopTime
7. Property cpuUser
8. Property cpuSystem

Title: Build Result


Type	`combining`
Required	No
Additional properties	Any type allowed

Description: This schema describes the JSON representation of Nix's BuildResult type, which represents the result of building a derivation or substituting store paths.

Build results can represent either successful builds (with built outputs) or various types of failures.

Property	Type	Pattern	Title/Description
- timesBuilt	integer	No	Times built
- startTime	integer	No	Start time
- stopTime	integer	No	Stop time
- cpuUser	integer	No	User CPU time
- cpuSystem	integer	No	System CPU time

One of(Option)
Successful Build Result
Failed Build Result

1. Property `Successful Build Result`

Title: Successful Build Result


Type	`object`
Required	No
Additional properties	Any type allowed
Defined in	#/$defs/success

Description: Represents a successful build with built outputs.

Property	Type	Pattern	Title/Description
+ success	const	No	Success indicator
+ status	enum (of string)	No	Success status
+ builtOutputs	object	No	Built outputs

1.1. Property `success`

Title: Success indicator


Type	`const`
Required	Yes

Description: Always true for successful build results.

Specific value: true

1.2. Property `status`

Title: Success status


Type	`enum (of string)`
Required	Yes

Description: Status string for successful builds.

Must be one of:

"Built"
"Substituted"
"AlreadyValid"
"ResolvesToAlreadyValid"

1.3. Property `builtOutputs`

Title: Built outputs


Type	`object`
Required	Yes
Additional properties	Each additional property must conform to the schema

Description: A mapping from output names to their build trace entries.

Property	Type	Pattern	Title/Description
-	object	No	Build Trace Entry

1.3.1. Property `Build Trace Entry`

Title: Build Trace Entry


Type	`combining`
Required	No
Additional properties	Not allowed
Defined in	build-trace-entry-v1.yaml

Description: A record of a successful build outcome for a specific derivation output.

This schema describes the JSON representation of a build trace entry.

Warning

This JSON format is currently experimental and subject to change.

Property	Type	Pattern	Title/Description
+ id	object	No	-
+ outPath	object	No	-
+ dependentRealisations	object	No	-
+ signatures	object	No	-

All of(Requirement)
Build Trace Key
Build Trace Value

1.3.1.1. Property `Build Trace Key`

Title: Build Trace Key


Type	`object`
Required	No
Additional properties	Any type allowed
Defined in	#/$defs/key

Description: A build trace entry is a key-value pair. This is the "key" part, refering to a derivation and output.

Property	Type	Pattern	Title/Description
+ id	string	No	Derivation Output ID

1.3.1.1.1. Property `id`

Title: Derivation Output ID


Type	`string`
Required	Yes

Description: Unique identifier for the derivation output that was built.

Format: {hash-quotient-drv}!{output-name}

hash-quotient-drv: SHA-256 hash of the quotient derivation. Begins with sha256:.
output-name: Name of the specific output (e.g., "out", "dev", "doc")

Example: "sha256:ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad!foo"

Restrictions
Must match regular expression	`^sha256:[0-9a-f]{64}![a-zA-Z_][a-zA-Z0-9_-]*$` Test

1.3.1.2. Property `Build Trace Value`

Title: Build Trace Value


Type	`object`
Required	No
Additional properties	Any type allowed
Defined in	#/$defs/value

Description: A build trace entry is a key-value pair. This is the "value" part, describing an output.

Property	Type	Pattern	Title/Description
+ outPath	string	No	Output Store Path
+ dependentRealisations	object	No	Underlying Base Build Trace
+ signatures	array of string	No	Build Signatures

1.3.1.2.1. Property `outPath`

Title: Output Store Path


Type	`string`
Required	Yes
Defined in	store-path-v1.yaml

Description: The path to the store object that resulted from building this derivation for the given output name.

Restrictions
Min length	34
Must match regular expression	`^[0123456789abcdfghijklmnpqrsvwxyz]{32}-.+$` Test

1.3.1.2.2. Property `dependentRealisations`

Title: Underlying Base Build Trace


Type	`object`
Required	Yes
Additional properties	Not allowed

Description: This is for derived build trace entries to ensure coherence.

Keys are derivation output IDs (same format as the main id field). Values are the store paths that those dependencies resolved to.

As described in the linked section on derived build trace traces, derived build trace entries must be kept in addition and not instead of the underlying base build entries. This is the set of base build trace entries that this derived build trace is derived from. (The set is also a map since this miniature base build trace must be coherent, mapping each key to a single value.)

Property	Type	Pattern	Title/Description
- ^sha256:[0-9a-f]{64}![a-zA-Z_][a-zA-Z0-9_-]*$	string	Yes	Dependent Store Path

1.3.1.2.2.1. Pattern Property `Dependent Store Path`

All properties whose name matches the regular expression ^sha256:[0-9a-f]{64}![a-zA-Z_][a-zA-Z0-9_-]*$ (Test) must respect the following conditions

Title: Dependent Store Path


Type	`string`
Required	No
Defined in	store-path-v1.yaml

Description: Store path that this dependency resolved to during the build

Restrictions
Min length	34
Must match regular expression	`^[0123456789abcdfghijklmnpqrsvwxyz]{32}-.+$` Test

1.3.1.2.3. Property `signatures`

Title: Build Signatures


Type	`array of string`
Required	Yes

Description: A set of cryptographic signatures attesting to the authenticity of this build trace entry.

	Array restrictions
Min items	N/A
Max items	N/A
Items unicity	False
Additional items	False
Tuple validation	See below

Each item of this array must be	Description
Signature	A single cryptographic signature

1.3.1.2.3.1. Signature

Title: Signature


Type	`string`
Required	No

Description: A single cryptographic signature

1.3.1.3. Property `id`


Type	`object`
Required	Yes
Additional properties	Any type allowed

1.3.1.4. Property `outPath`


Type	`object`
Required	Yes
Additional properties	Any type allowed

1.3.1.5. Property `dependentRealisations`


Type	`object`
Required	Yes
Additional properties	Any type allowed

1.3.1.6. Property `signatures`


Type	`object`
Required	Yes
Additional properties	Any type allowed

2. Property `Failed Build Result`

Title: Failed Build Result


Type	`object`
Required	No
Additional properties	Any type allowed
Defined in	#/$defs/failure

Description: Represents a failed build with error information.

Property	Type	Pattern	Title/Description
+ success	const	No	Success indicator
+ status	enum (of string)	No	Failure status
+ errorMsg	string	No	Error message
- isNonDeterministic	boolean	No	Non-deterministic flag

2.1. Property `success`

Title: Success indicator


Type	`const`
Required	Yes

Description: Always false for failed build results.

Specific value: false

2.2. Property `status`

Title: Failure status


Type	`enum (of string)`
Required	Yes

Description: Status string for failed builds.

Must be one of:

"PermanentFailure"
"InputRejected"
"OutputRejected"
"TransientFailure"
"CachedFailure"
"TimedOut"
"MiscFailure"
"DependencyFailed"
"LogLimitExceeded"
"NotDeterministic"
"NoSubstituters"
"HashMismatch"

2.3. Property `errorMsg`

Title: Error message


Type	`string`
Required	Yes

Description: Information about the error if the build failed.

2.4. Property `isNonDeterministic`

Title: Non-deterministic flag


Type	`boolean`
Required	No

Description: If timesBuilt > 1, whether some builds did not produce the same result.

Note that 'isNonDeterministic = false' does not mean the build is deterministic, just that we don't have evidence of non-determinism.

3. The following properties are required

success
status

4. Property `timesBuilt`

Title: Times built


Type	`integer`
Required	No

Description: How many times this build was performed.

Restrictions
Minimum	≥ 0

5. Property `startTime`

Title: Start time


Type	`integer`
Required	No

Description: The start time of the build (or one of the rounds, if it was repeated), as a Unix timestamp.

Restrictions
Minimum	≥ 0

6. Property `stopTime`

Title: Stop time


Type	`integer`
Required	No

Description: The stop time of the build (or one of the rounds, if it was repeated), as a Unix timestamp.

Restrictions
Minimum	≥ 0

7. Property `cpuUser`

Title: User CPU time


Type	`integer`
Required	No

Description: User CPU time the build took, in microseconds.

Restrictions
Minimum	≥ 0

8. Property `cpuSystem`

Title: System CPU time


Type	`integer`
Required	No

Description: System CPU time the build took, in microseconds.

Restrictions
Minimum	≥ 0

Examples

Successful build

{
  "builtOutputs": {
    "bar": {
      "dependentRealisations": {},
      "id": "sha256:6f869f9ea2823bda165e06076fd0de4366dead2c0e8d2dbbad277d4f15c373f5!bar",
      "outPath": "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-bar",
      "signatures": []
    },
    "foo": {
      "dependentRealisations": {},
      "id": "sha256:6f869f9ea2823bda165e06076fd0de4366dead2c0e8d2dbbad277d4f15c373f5!foo",
      "outPath": "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo",
      "signatures": []
    }
  },
  "cpuSystem": 604000000,
  "cpuUser": 500000000,
  "startTime": 30,
  "status": "Built",
  "stopTime": 50,
  "success": true,
  "timesBuilt": 3
}

Failed build (output rejected)

{
  "errorMsg": "no idea why",
  "isNonDeterministic": false,
  "startTime": 30,
  "status": "OutputRejected",
  "stopTime": 50,
  "success": false,
  "timesBuilt": 3
}

Failed build (non-deterministic)

{
  "errorMsg": "no idea why",
  "isNonDeterministic": false,
  "startTime": 0,
  "status": "NotDeterministic",
  "stopTime": 0,
  "success": false,
  "timesBuilt": 1
}

Determinate Nix 3.14.0 Reference Manual

Build Result

1. Property Successful Build Result

1.1. Property success

1.2. Property status

1.3. Property builtOutputs

1.3.1. Property Build Trace Entry

1.3.1.1. Property Build Trace Key

1.3.1.1.1. Property id

1.3.1.2. Property Build Trace Value

1.3.1.2.1. Property outPath

1.3.1.2.2. Property dependentRealisations

1.3.1.2.2.1. Pattern Property Dependent Store Path

1.3.1.2.3. Property signatures

1.3.1.2.3.1. Signature

1.3.1.3. Property id

1.3.1.4. Property outPath

1.3.1.5. Property dependentRealisations

1.3.1.6. Property signatures

2. Property Failed Build Result

2.1. Property success

2.2. Property status

2.3. Property errorMsg

2.4. Property isNonDeterministic