1
- # Architectural Decision Record: Rework of Referebce Hints
1
+ # ADR-0003 - Rework of Reference Hints
2
+
3
+ - Status: proposed
4
+ - Date: 2024-12-27
5
+ - Authors: @mandelsoft
6
+ - Deciders: @fabianburth @jakobmoellerdev
7
+ - Reference Implementation: #1212
2
8
3
9
### Meaning of Reference Hints
4
10
5
11
During the transport of software artifacts referenced from external artifact repositories like
6
12
OCI registries, they might be stored as blobs along with the component version (access method
7
- ` localBlob ` . If those component versions are transported again into a repository landscape they
13
+ ` localBlob ` ) . If those component versions are transported again into a repository landscape they
8
14
might be uploaded again to external repositories.
9
15
10
16
To provide useful identities for storing those artifacts hints in external repositories, again,
11
17
the original identity of the external artifact must be stored along with the local blob.
12
18
13
19
### Current Solution
14
20
15
- The access method origibally used to refernce the exterbal artfact provides a reference hint,
21
+ The access method originally used to reference the external artifact provides a reference hint,
16
22
which can later be used by the blob uploaders to reconstruct a useful identity.
17
23
Therefore, the ` localBlob ` access method is able to keep track of this hint value.
18
- The hint is just a string, which needs to be intepreted by the uploader.
24
+ The hint is just a string, which needs to be interpreted by the uploader.
19
25
20
26
### Problems with Current Solution
21
27
22
- The assumprion behind the current solution is that the uploader will always upload the
23
- artifactinto a similar repository, again. Therefore, there would be a one-to-one relation
28
+ The assumption behind the current solution is that the uploader will always upload the
29
+ artifact into a similar repository, again. Therefore, there would be a one-to-one relation
24
30
between access method and uploader.
25
31
26
32
Unfortunately this is not true in all cases:
27
33
- There are access methods now (like` wget ` ), which are able to handle any kind of artifact blob
28
- with different natural repositoty types and identity schemes.
34
+ with different natural repository types and identity schemes.
29
35
- Therefore,
30
36
- it can neither provide an implicit reference hint anymore
31
37
- nor there is a one-to-one relation to a typed uploader anymore.
32
38
- artifacts might be uploadable to different repository types using different
33
39
identity schemes.
34
40
35
41
This problem is partly covered by allowing to specify a hint along with those access methods
36
- similar to the ` localBlob ` access method. But this can only be a workarround , because
37
- - the hint is not typed and potential target repositories might use diufferent identity schemes
42
+ similar to the ` localBlob ` access method. But this can only be a workaround , because
43
+ - the hint is not typed and potential target repositories might use different identity schemes
38
44
- it is possible to store a single hint, only.
39
45
40
46
### Proposed Solution
41
47
42
- Hints have to be typed, to allow uploaders to know what identites are provided and how the
48
+ Hints have to be typed, to allow uploaders to know what identities are provided and how the
43
49
hint string has to be interpreted. Additionally, it must be possible to store
44
- mulltiple hints for an artifact.
50
+ multiple hints for an artifact.
45
51
46
52
To be compatible a serialization format is defined for a list of type hints, which maps such
47
53
a list to a single string.
@@ -51,33 +57,49 @@ a formal hint, by providing access to a set of string attributes. There are thre
51
57
attributes:
52
58
- ` type ` the formal type of the hint (may be empty to cover old component versions)
53
59
The types are defined like the resource types. The following types are defined for now:
54
- - ` oci ` : OCI identity given by the attribute ` reference ` with the cirrently used format
60
+ - ` oci ` : OCI identity given by the attribute ` reference ` with the currently used format
55
61
- ` maven ` : Maven identity (GAV) given by the attribute ` reference ` with the currently used format
56
62
- ` npm ` : Node package identity given by the attribute ` reference ` with the currently used
57
63
format
58
64
- ` reference ` : the standard attribute to hold a string representation for the identity.
59
65
- ` implicit ` : Value ` true ` indicated an implicit hint (as used today) provided by an accessmethods.
60
66
61
- New Hint types my use other attributes.
67
+ Typeless former hints are represented by the sole attribute ` reference ` .
68
+ New Hint types may use other attributes.
69
+
70
+ #### Access Methods
62
71
63
- An access method can provide (and store) implicit hints as before. THose hints are indicated
72
+ An access method can provide (and store) implicit hints as before. Those hints are indicated
64
73
to be implicit. When composing an access method it is only allowed to store implicit hints.
65
74
This is completely compatible to the current solution.
66
75
67
- Additionally, multiplehints can be stored abd delivered.
76
+ Additionally, multiple hints can be stored abd delivered.
68
77
69
78
To support any kind of hint for any scenario, the artifact metadata (resources and sources)
70
79
is extended to store explicit hints, which will be part of the normalized form.
71
80
This is done by an additional attribute ` referenceHints ` . It is a list of string maps
72
81
holding the hint attributes (including the hint type).
73
82
74
- Uploaders are called with the aggrgation of explicit (from metadata) and implicit (from
83
+ #### Uploaders
84
+
85
+ Uploaders are called with the aggregation of explicit (from metadata) and implicit (from
75
86
access methods) hints. Hereby, the explicit hints have precedence.
76
87
77
88
If an uploader creates a local access specification, only implicit hints may be stored, here.
78
89
79
90
There is a new composition option (` --refhint ` ) now for composing resources
80
- and sources for the CLI. It accepts an attribute setting. Multiple such options starting with the ` type ` attribute are used to compose a single hint.
91
+ and sources for the CLI. It accepts an attribute setting. Multiple such options starting with the ` type ` attribute are used to compose a single hint.
92
+
93
+ #### Inputs
94
+
95
+ Inputs may provide explicit or implicit hints, now. All file based inputs now allow to specify implicit hints as used before.
96
+ The implicit hints (if not conflicting with explicit hints) are used to be stored in ` localBlob `
97
+ access methods. The explicit hints are used to default the explicit artifact hints.
98
+
99
+ Hints used in a component version must be unique. This check is extended to consider implicit
100
+ and explicit hints provided by inputs, access methods and artifact hints.
101
+
102
+ Hints may either be specified as a list of string maps (canonical form) or as string using the serialized from.
81
103
82
104
### Hint Serialization Format
83
105
@@ -86,28 +108,28 @@ In general a hint is serialized to the following string
86
108
[<*type*>`::]`<*attribute*>`=`<*value*>{`,`<*attribute*>`=`<*value*>}
87
109
</center >
88
110
89
- The type is not serilaized as attribute. The ` implicit ` attribute is never serialized is the string is stored in an access specification.
90
- If no type is known the type part is omiited .
111
+ The type is not serialized as attribute, but as prefix separated by a ` :: ` . The ` implicit ` attribute is never serialized if the string is stored in an access specification.
112
+ If no type is known the type part is omitted .
91
113
92
114
A list of hints is serialized to
93
115
94
116
<center >
95
117
< ; * hint* >{` ; ` < ; * hint* >}
96
118
</center >
97
119
98
- * Attributes* names consist of alpha numeric chaŕacters , only.
99
- If a * value* may not cotain a ` :: ` . If it contains a ` ; ` , ` , ` or ` " `
120
+ * Attributes* names consist of alphanumeric characters , only.
121
+ A * value* may not contain a ` :: ` . If it contains a ` ; ` , ` , ` or ` " `
100
122
character it must be given in double quotes.
101
- In the double quote form any ` " ` or ` \ ` character has to be escaped by
123
+ In the double-quoted form any ` " ` or ` \ ` character has to be escaped by
102
124
a preceding ` \ ` character.
103
125
104
126
To be as compatible as possible, a single attribute hint with the attribute
105
127
` reference ` is serialized as naked value (as before) if there are no special
106
128
characters enforcing a quoted form.
107
129
108
- ### Incompatible Changes:
130
+ ### Incompatible Changes
109
131
110
- #### Componwnt Version Representation
132
+ #### Component Version Representation
111
133
112
134
- The new library creates always typed hints for new elements. Old hints are
113
135
left as they are. This means, that old versions of the OCM tooling
@@ -123,7 +145,7 @@ characters enforcing a quoted form.
123
145
124
146
- Uploaders provided by a plugin now get a serialized hint list
125
147
instead of a simple untyped reference format.
126
- -
148
+
127
149
- There are new options for creating resource(source access objects.
128
150
129
151
0 commit comments