-
Notifications
You must be signed in to change notification settings - Fork 2
/
Copy pathREADME
172 lines (118 loc) · 6.73 KB
/
README
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
orc - The Open Registers Compendium
===================================
Copyright (C) 2018-2019, Andy Bennett and Simon Worthington, Register Dynamics Limited.
1. Introduction
Open Registers are a way of expressing an authoritative list that you
can trust. orc is an implementation of the Open Registers data model
as well as the more specific gov.uk Registers model.
This repository is an umbrella for a variety of tools that work
together to implement various parts of the model:
+ chicken/orc - A full, persistent, merkle tree backed implementation of
Open Registers.
The files in this repository are distributed under a range of
licenses. However they are, in general, free to use and modify as long
as you agree to the terms. Please see the LICENSE files in each
directory for more information.
Note: Should you have any trouble in setting up and using these tools,
please feel free to contact me, Andy Bennett at
andyjpb@register-dynamics.co.uk.
2. Installation
Building the tools in this package requires GNU Make and a recent
CHICKEN Scheme.
2.1. Building from git
Build and install the orc egg for CHICKEN Scheme thus:
$ cd chicken/
$ chicken-install
2.2. What gets installed
+ CHICKEN Scheme library egg
The library contains the necessary functions to read Registers,
store them persistently, update the entries in the Register,
and compute proofs and digests on the data.
+ `orc` command line tool
The command line tool exposes the functionality of the library
on the command line. The tool can read from either Register
Serialisation Format (RSF) files or orc internal databases,
and can list and modify Register entries and items.
3. Usage
The library can be included in a CHICKEN Scheme environment by using
`(use orc)`, which will bring the exported API into scope.
3.1 Backing stores
All calls to library methods must be made in the context of a
'backing store'. This is an internal database type the orc uses to
store and manipulate Registers.
A backing store can be opened with `open-backing-store` which will
either open an existing file or create one if it does not exist. If
the backing store is new, it must also be initialised with
`initialise-backing-store`. Stores can also be created and initialised
automatically by passing the `-S` option to the command line tool.
Once a backing store has been opened, library calls can be made inside
a call to `with-backing-store`.
(use orc)
(define my-backing-store (open-backing-store "my.backing-store"))
(with-backing-store my-backing-store (lambda ()
(for-each display (list-registers))))
3.2 Registers
New Registers can be created using `make-register`, which takes an internal
name to associate with the new Register.
Registers in a backing store can be listed with the `list-registers`
command. This will return a list of Register objects that can be passed
to other functions, along with the internal name. Individual Registers can
also be opened directly by passing their internal name to `open-register`.
Register objects represent a specific version of a specific Register. For
this reason, any methods that modify a Register also return a new Register
object representing the new version. This new object must be used from
this point onwards to make further modifications to the Register. Edit
functions will fail and complain if an old Register version is used.
An optional version number can also be passed to `open-register` which
opens the Register at that version. This is useful for examining the data
at a previous time.
3.3 Records
A Register entry is an association between a key and some values. Each
key is unique but it can be associated with multiple values at once if
desired. A Register contains all of the entries that have ever been
written to it, but not all of them are current.
Entries exist in one of two regions – the system region or the user
region. The system region contains Register metadata such as its schema
while the user region contains the actual data in the Register.
A record is an entry in the Register that is current – there is no more
recent entry with that specific key. Records can be listed for a Register
with `register-records`. Each record can be interrogated using the
`entry-region`, `entry-key`, `entry-ts` (timestamp) and `entry-items`.
Records for a given key can be looked up with `register-record-ref`.
Key objects can be made using `make-key` or `string->key`, and also
come with eqaulity and comparison operators.
Entries can be created using `make-entry`, which takes values for all
the metadata attributes and a list of items. Newly created entries must
then be passed to `register-append-entry` to add them to the Register.
3.4 Items
An item is the actual unit of data in a Register entry. Each entry can
have multiple items. An entry with zero items is valid but is considered
to be 'deleted' and will not be returned by `register-records`.
Items are not contained within an entry – they exist in a separate space
and are linked to by an entry through an item reference. The reference
is normally the SHA256 digest of the item contents.
Items are retrieved from an entry using `entry-items`. Item references
can be retrieved using `item-item-ref` and the content through `item-blob`.
Items can be created using `make-item`. Newly created items must then
be passed to `register-add-item` to add them to the Register. This must
happen before any entries that contain them are added.
3.5 Register Serialisation Format (RSF)
An RSF file contains the entire contents and history of a Register.
Registers can be loaded from RSF files using `read-rsf`, which will read
an RSF file from `(current-input-port)` and add it to the backing store
with a passed internal name.
There is not currently any support for writing to RSF files.
3.X Command line tool
The `orc` command line tool can be invoked with the `--help` switch
to print full usage information.
4. Compatibility notes
5. What's next?
First and foremost, enjoy the tools and use and extend them to build
your own things for processing register data.
Please feel free to send tools that you build with orc so that they
can be integrated and distributed with this package.
Suggestion, extensions and patches to orc are welcome.
If you have any questions or problems (even the slightest problems, or
the most stupid questions), then please feel free to get in touch with
me directly using the addresses above. I will try to help you, get you
going or point you in the right direction.