topdown: Add units.parse builtin.

This function works on all base decimal and binary SI units of the set:

    m, K/Ki, M/Mi, G/Gi, T/Ti, P/Pi, and E/Ei

Note: Unlike `units.parse_bytes`, this function is case sensitive.

Fixes open-policy-agent#1802.

Signed-off-by: Philip Conrad <philipaconrad@gmail.com>

ast/builtins.go

@@ -255,6 +255,7 @@ var DefaultBuiltins = [...]*Builtin{
 	GlobQuoteMeta,
 
 	// Units
+	UnitsParse,
 	UnitsParseBytes,
 
 	// UUIDs
@@ -1123,6 +1124,18 @@ var NumbersRange = &Builtin{
  * Units
  */
 
+// UnitsParse converts strings like 10G, 5K, 4M, 1500m and the like into a
+// number. This number can be a non-integer, such as 1.5, 0.22, etc.
+var UnitsParse = &Builtin{
+	Name: "units.parse",
+	Decl: types.NewFunction(
+		types.Args(
+			types.S,
+		),
+		types.N,
+	),
+}
+
 // UnitsParseBytes converts strings like 10GB, 5K, 4mb, and the like into an
 // integer number of bytes.
 var UnitsParseBytes = &Builtin{

capabilities.json

@@ -3627,6 +3627,20 @@
         "type": "function"
       }
     },
+    {
+      "name": "units.parse",
+      "decl": {
+        "args": [
+          {
+            "type": "string"
+          }
+        ],
+        "result": {
+          "type": "number"
+        },
+        "type": "function"
+      }
+    },
     {
       "name": "units.parse_bytes",
       "decl": {

docs/content/policy-reference.md

@@ -459,6 +459,7 @@ The following table shows examples of how ``glob.match`` works:
 
 | Built-in | Description | Wasm Support |
 | ------- |-------------|---------------|
+| <span class="opa-keep-it-together">``output := units.parse(x)``</span> | ``output`` is ``x`` converted to a number with support for standard metric decimal and binary SI units (e.g., K, Ki, M, Mi, G, Gi etc.) m, K, M, G, T, P, and E are treated as decimal units and Ki, Mi, Gi, Ti, Pi, and Ei are treated as binary units. Note that 'm' and 'M' are case-sensitive, to allow distinguishing between "milli" and "mega" units respectively. Other units are case-insensitive. | ``SDK-dependent`` |
 | <span class="opa-keep-it-together">``output := units.parse_bytes(x)``</span> | ``output`` is ``x`` converted to a number with support for standard byte units (e.g., KB, KiB, etc.) KB, MB, GB, and TB are treated as decimal units and KiB, MiB, GiB, and TiB are treated as binary units. The bytes symbol (b/B) in the unit is optional and omitting it wil give the same result (e.g. Mi and MiB) | ``SDK-dependent`` |
 
 ### Types

test/cases/testdata/units/test-parse-units-comparisons.yaml

@@ -0,0 +1,111 @@
+cases:
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("8k") > units.parse("7k")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("8g") > units.parse("8m")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("1234k") < units.parse("1g")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("1024") == units.parse("1Ki")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("2Mi") == units.parse("2097152")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("3Mi") > units.parse("3M")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("2Mi") == units.parse("2Mi")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("4Mi") > units.parse("4M")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("4.1Mi") > units.parse("4Mi")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("128Gi") == units.parse("137438953472")
+    }
+  note: parse/comparison
+  query: data.test.p = x
+  want_result:
+  - x: true

test/cases/testdata/units/test-parse-units-errors.yaml

@@ -0,0 +1,78 @@
+cases:
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: no amount provided"
+  strict_error: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("G")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: no amount provided"
+  strict_error: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("foo")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: no amount provided"
+  strict_error: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("0.0.0")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: could not parse amount to a number"
+  strict_error: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse(".5.2")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: could not parse amount to a number"
+  strict_error: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse("100 k")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: spaces not allowed in resource strings"
+  strict_error: true
+- data:
+  modules:
+  - |
+    package test
+    p {
+        units.parse(" 327Mi ")
+    }
+  note: parse/failure
+  query: data.test.p = x
+  want_error: "units.parse error: spaces not allowed in resource strings"
+  strict_error: true